Mohr CT100, CT100HF Operator's Manual

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Operator's Manual

CT100 and CT100HF

Automated Metallic Time-Domain Reflectometers

Part No.: CT100-M-OM-004

CAGE Code: 4JEE1

Revised: August 12, 2013

Reproduction of this manual in print and electronic form is authorized for U.S. Government purposes only. This manual may not be reproduced, distributed, transmitted, displayed, published or broadcast in any form or medium by any other party without written permission from MOHR.

MOHR products are covered by U.S. and foreign patents, issued and pending. Information in this publication supersedes all previously published material. MOHR reserves the right to change product specifications or pricing at any time without notice.

MOHR Test and Measurement, 1440 Agnes Street, Richland, WA 99352 USA

Warranty

Purchase and/or use of this product signifies your agreement to the terms of this Warranty. MOHR Test and Measurement LLC (MOHR) warrants that this product will be free from defects in materials and workmanship for a period of one (1) year from the date of shipment. If any such product proves defective during this warranty period, MOHR, at its option, either will repair the defective product without charge for parts and labor, or will provide a replacement in exchange for the defective product.

In order to obtain service under this Warranty, customers must notify MOHR of the defect before the expiration of the warranty period and make suitable arrangements for the performance of service. Customers shall be responsible for packaging and shipping the defective product to MOHR with shipping charges prepaid. Customer shall be responsible for paying all return shipping charges, duties, taxes, and other charges for units returned to any location.

This Warranty is given by MOHR with respect to this product in lieu of any other warranties expressed or implied. MOHR and its vendors disclaim any implied warranties of merchantability or fitness for a particular purpose. MOHR’s responsibility to repair or replace defective units is the sole and exclusive remedy provided to the customer for breach of the Warranty. MOHR and its vendors will not be liable for any indirect, special, incidental, or consequential damages irrespective of whether MOHR or the vendor has advance notice of the possibility of such damages.

Specific limitations of this Warranty:

This Warranty only applies to normal and reasonable use of this product. Damage to this product resulting from improper use, the determination of which is solely at the discretion of MOHR, is specifically excluded from this Warranty.

Electrical damage to this product resulting from connection of a cable or device carrying a static electrical charge to the front panel BNC connector or SMA connector without first properly grounding the conducting elements of the cable or device is specifically excluded from this Warranty.

Electrical damage to this product resulting from connection of a cable or device carrying an electrical signal or other non-zero electrical potential relative to earth ground to the front panel BNC connector or SMA connector is specifically excluded from this Warranty.

iii

Contacting

Phone

Sales 1-509-946-0941 Technical Support 1-509-946-2240 Toll-free 1-888-852-0408

Mail

MOHR Test and Measurement 1440 Agnes Street Richland, WA 99352 USA

E-mail

info@mohrandassociates.com

MOHR Test and Measurement

Web

www.mohr-engineering.com

Table of Contents

Copyright Notice.................................................................................................................................ii

Warranty.............................................................................................................................................iii

Contacting MOHR Test and Measurement.......................................................................................iv

Phone............................................................................................................................................iv

Mail................................................................................................................................................iv

E-mail............................................................................................................................................iv

Web...............................................................................................................................................iv

General Information............................................................................................................................1

Product description........................................................................................................................1

Battery pack and AC power requirements.....................................................................................2

Options and accessories................................................................................................................2

Unpacking and initial inspection....................................................................................................2

Repacking for shipment.................................................................................................................2

Safety Summary.................................................................................................................................5

Terms in the manual......................................................................................................................5

Terms on the product.....................................................................................................................5

DANGER....................................................................................................................................5

WARNING ................................................................................................................................5

CAUTION...................................................................................................................................5

Symbols in the manual...................................................................................................................6

Symbols on the product.................................................................................................................6

Static charge..................................................................................................................................6

Fuses.............................................................................................................................................6

AC power source...........................................................................................................................6

Grounding the CT100....................................................................................................................7

Danger arising from loss of ground................................................................................................7

Explosive atmospheres..................................................................................................................8

Do not remove covers or panels....................................................................................................8

Connecting cables to the front panel BNC....................................................................................8

Battery replacement and disposal.................................................................................................8

Operating Instructions........................................................................................................................9

Overview........................................................................................................................................9

Handling.....................................................................................................................................9

Powering the CT100..................................................................................................................9

Caring for the battery...............................................................................................................10

Charging and power status......................................................................................................10

Batteries and long-term storage..............................................................................................11

Low battery..............................................................................................................................11

Preparing to use the CT100.........................................................................................................12

Front panel controls and connectors...........................................................................................12

Rear panel connectors and switches...........................................................................................15

Setting up the CT100...................................................................................................................16

Setting date and time...............................................................................................................16

Navigating dialog boxes..........................................................................................................16

Display features...........................................................................................................................17

License codes..............................................................................................................................17

Menu selections and function buttons.........................................................................................18

M-FUNC button........................................................................................................................18

SCAN button and menu...........................................................................................................18

SELECT button........................................................................................................................20

AUTOFIT..................................................................................................................................20

CURSOR.................................................................................................................................20

LIBRARY button and menu.....................................................................................................20

MENU button and top-level menu selections..........................................................................21

Test preparations.........................................................................................................................32

Velocity of propagation............................................................................................................32

Change Vp...............................................................................................................................32

Find an unknown Vp................................................................................................................33

Temperature correction...........................................................................................................34

Cable test procedures..................................................................................................................34

Distance to fault.......................................................................................................................34

Common types of cable faults.................................................................................................37

Reflection coefficient measurements......................................................................................39

Return loss measurements......................................................................................................39

Ohms-at-cursor........................................................................................................................40

VSWR......................................................................................................................................40

Relative distance measurements............................................................................................40

Scan a trace.............................................................................................................................41

Select a trace...........................................................................................................................41

Store a trace............................................................................................................................43

Load a trace (cable records)....................................................................................................44

Storage space..........................................................................................................................45

View the difference between traces........................................................................................46

View a first derivative of a trace...............................................................................................47

View a Fast Fourier Transform of a trace................................................................................47

View S-Param trace.................................................................................................................48

Calibrated S-Param trace........................................................................................................48

Remote control........................................................................................................................48

Cable type................................................................................................................................49

Measurement...........................................................................................................................49

Configurations..........................................................................................................................52

CT Viewer™.....................................................................................................................................53

Options and Accessories.................................................................................................................55

Options ........................................................................................................................................55

Accessories .................................................................................................................................55

Standard accessories (CT100)................................................................................................55

Standard high-frequency accessories (CT100HF)..................................................................55

Optional accessories (CT100 / CT100HF)..............................................................................56

Service accessories (CT100 / CT100HF)................................................................................56

Appendix A: Specifications..............................................................................................................57

Electrical specifications................................................................................................................57

Mechanical specifications............................................................................................................59

Weight......................................................................................................................................59

Dimensions..............................................................................................................................59

Environmental specifications.......................................................................................................59

Temperature............................................................................................................................59

Certifications and Compliances...................................................................................................60

EC............................................................................................................................................60

FCC Compliance.....................................................................................................................60

Appendix B: Subassembly Drawings and Parts List.......................................................................61

Subassembly drawings................................................................................................................61

Parts list.......................................................................................................................................68

Appendix C: Operator Performance Check....................................................................................71

General information.....................................................................................................................71

Required equipment.....................................................................................................................71

Getting ready................................................................................................................................71

Reflected Rise Time Check (10-90%).........................................................................................72

Reflected Rise Time Check (20-80%).........................................................................................73

Jitter, Noise, and Sampling Efficiency Check..............................................................................73

Output Impedance Check............................................................................................................73

Pulse Amplitude Check................................................................................................................74

Pulse Width Check.......................................................................................................................74

Pulse Repetition Rate Check.......................................................................................................74

Sequential Sampling Rate Check................................................................................................75

Vertical Scale Check....................................................................................................................75

Vertical Accuracy Check..............................................................................................................75

Vertical Position Check................................................................................................................75

Input Susceptibility Check............................................................................................................75

Distance Cursor Resolution Check..............................................................................................75

Cursor Readout Range Check.....................................................................................................75

Cursor Readout Resolution Check..............................................................................................76

Distance Measurement Accuracy Check.....................................................................................76

Ohm Readout Range Check........................................................................................................76

Resolution Check.........................................................................................................................76

Vertical Accuracy Check..............................................................................................................77

Horizontal Scale Check................................................................................................................77

Horizontal Range Check..............................................................................................................77

Horizontal Position Check............................................................................................................77

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Pulse Frequency Check...............................................................................................................77

Appendix D: Calibration Procedures...............................................................................................79

General information.....................................................................................................................79

Calibration interval.......................................................................................................................79

Required equipment.....................................................................................................................79

Getting ready................................................................................................................................79

Pulse measurement checks (optional).........................................................................................80

Turn off temperature adjustment.................................................................................................80

Set manual calibration values......................................................................................................81

Capacitive load calibration...........................................................................................................81

Driver start calibration..................................................................................................................82

Resistive load calibration.............................................................................................................82

Vertical calibration........................................................................................................................82

Manually verify calibration values................................................................................................82

Manually verify capacitive calibration......................................................................................82

Manually verify resistive load calibration.................................................................................84

Enable temperature adjustment...................................................................................................87

Horizontal calibration...................................................................................................................87

Clear temperature lookup table...................................................................................................89

Appendix E: Operator Troubleshooting...........................................................................................91

General information.....................................................................................................................91

Power on test...............................................................................................................................91

Functional block diagram and troubleshooting flowcharts...........................................................91

Appendix F: Vp of Common Cables..............................................................................................103

Cable types................................................................................................................................103

Dielectric material..................................................................................................................103

RG standards.........................................................................................................................103

MIL-C-17 standards...............................................................................................................104

Commercial designations......................................................................................................105

Twisted pair...........................................................................................................................105

Appendix G: Maintenance and Service Instructions.....................................................................107

Cleaning and lubrication............................................................................................................107

Cleaning and lubrication interval................................................................................................107

Battery removal..........................................................................................................................107

Inspection...................................................................................................................................108

Inspection interval......................................................................................................................108

Calibration and calibration interval.............................................................................................108

Glossary.........................................................................................................................................109

Index...............................................................................................................................................115

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List of Figures

Figure 1: Diagram of the front panel of the CT100 / CT100HF......................................................12

Figure 2: Diagram of the rear panel of the CT100 / CT100HF.......................................................15

Figure 3: Screenshot showing typical features of the CT100 display.............................................17

Figure 4: Screenshot showing AUTOFIT result..............................................................................33

Figure 5: Screenshot showing Vp determination............................................................................34

Figure 6: AUTOFIT cable................................................................................................................35

Figure 7: After adjusting the vertical scale......................................................................................36

Figure 8: A zoomed-in view of the cable fault.................................................................................36

Figure 9: An open cable fault..........................................................................................................37

Figure 10: A short cable fault..........................................................................................................37

Figure 11: An open cable fault at 1000 ft........................................................................................38

Figure 12: A 50 Ω to 75 Ω BNC to SMA interconnect.....................................................................41

Figure 13: Screenshots showing selection of a live trace...............................................................42

Figure 14: Saving a trace................................................................................................................43

Figure 15: Loading a trace..............................................................................................................44

Figure 16: Difference trace..............................................................................................................46

Figure 17: First-derivative plot.........................................................................................................47

Figure 18: CT100 complete mechanical and electrical assembly..................................................62

Figure 19: CT207 (power) subassembly.........................................................................................63

Figure 20: CT208 (analog) subassembly........................................................................................64

Figure 21: CT209 (back panel) subassembly.................................................................................65

Figure 22: CT290 (front panel) subassembly.................................................................................66

Figure 23: CT290HF (front panel) subassembly.............................................................................67

Figure 24: Trace preparation for rise time measurement...............................................................72

Figure 25: Cursor placement for determination of 10-90% rise time..............................................73

Figure 26: Example of an incomplete capacitive calibration...........................................................83

Figure 27: Example of a correctly set capacitive calibration...........................................................84

Figure 28: Typical trace from a CT100 with a shorting terminator applied to the test port.............85

Figure 29: Hybrid Comp adjustment with open BNC and cursor at the reflected rise....................85

Figure 30: Hybrid Comp adjustment with open terminator, detail...................................................86

Figure 31: Hybrid Comp adjustment with the shorting terminator..................................................86

Figure 32: Hybrid Comp adjustment with the shorting terminator, detail........................................87

Figure 33: Identification of cable start position...............................................................................88

List of Tables

Electrical specifications....................................................................................................................57

Mechanical specifications: weight....................................................................................................59

Mechanical specifications: dimensions............................................................................................59

Environmental specifications............................................................................................................59

Subassemblies and parts list...........................................................................................................68

Cable types: Dielectric materials....................................................................................................103

Cable types: RG standards............................................................................................................103

Cable types: MIL-C-17 standards..................................................................................................104

Cable types: Commercial designations..........................................................................................105

Cable types: Twisted pair...............................................................................................................105

General Information

Product description

The MOHR CT100 / CT100HF Automated Metallic Time-Domain Reflectometers (MTDRs) use a form of closed-circuit radar known as Time-Domain Reflectometry (TDR) to test cables for defects. These instruments apply a very fast risetime step signal to the cable under test and then measure the reflected voltage at very short time intervals. The resultant TDR trace allows the operator to identify changes in impedance within the cable indicating the presence of faults such as opens, shorts, kinks, defects in the shield or conductor, foreign substances such as water, or thermal damage. The CT100 and CT100HF can find extremely subtle cable defects that may be missed by other testing devices.

The CT100 series TDRs have specifications unmatched by any other commercially-available metallic TDR cable tester. Both devices feature timebase resolution of 0.76 ps regardless of cable length, equivalent to approximately 75 μm in coaxial cable with a Vp of 0.66. This allows for extremely precise cable length measurements and localization of cable defects. Fast system risetimes ensure excellent spatial resolution and make these instruments particularly valuable for troubleshooting modern high-frequency analog/RF and digital communications systems.

The CT100 is able to perform continuous sequential sampling at up to 250 kHz, continuously acquiring up to 500 full 500-point TDR traces per second. In concert with the CT100's high-speed internal 32-bit processor, this allows for rapid automated cable scans, sophisticated real-time digital filtering techniques (averaging, subtraction, derivatives, and more), and accurate characterization of transient cable defects.

The CT100 can store hundreds of full-length high-resolution cable scans or several thousand short or lower-resolution cable scans in its standard 2 GB internal non-volatile flash memory. These scans are easy to call up for comparison so that changes in cable integrity over time can be accurately assessed. To enter data, use the built-in software keyboard or plug an external barcode reader or keyboard into the front-panel USB connector. It is easy to connect the CT100 to a host PC using 10/100 Ethernet or USB to view, analyze, and store your data.

In the remaining sections, the specific requirements, capabilities, and operation of the CT100 and CT100HF are described in detail. Unless otherwise specified, any reference to the CT100 is true of the CT100HF as well. Figures in this text were acquired using both CT100 and CT100HF devices.

Mohr CT100 / CT100HF Operator's Manual 1

General Information

Battery pack and AC

The CT100 may be operated using either the supplied AC adapter, the internal NiMH batteries (for a minimum 6 hours operating time, typical use), or optional hot-swappable external 14.4 VDC battery packs (for unlimited portable use). The internal NiMH battery charges under AC during normal operation.

The external AC power adapter is intended to be used with either a 120 VAC or 240 VAC RMS power source. Use of a standard 3-prong AC socket with intact ground connection is essential for safe operation of the CT100 with the included AC power adapter. Review the Safety Summary section before operating the CT100.

Options and accessories

Options and accessories available for the CT100 are described on page 53.

Unpacking

Before opening the shipping package containing the CT100, first inspect it for signs of damage. If there is evidence of damage to the shipping package, notify both the shipping carrier and MOHR.

and initial

power requirements

inspection

The shipping container should contain the CT100 and standard accessories, including an Operator's Manual, front panel cover, external AC adapter and power cord, soft transit case, and calibration fixture(s). If the shipping container is intact but there are missing items or if the CT100 is damaged, defective, or does not meet operational requirements, contact a MOHR-authorized sales representative.

Repacking

When the CT100 needs to be shipped to a MOHR-authorized service center for repair, calibration, or other service, affix a label to the outside of the shipping container indicating the name, address, phone, and e-mail of the owner, the name of the MOHR service representative who was contacted regarding the shipment, the serial number of the instrument, and a description of the problem with the instrument and/or the desired service or maintenance.

Optimally, the original shipping carton and packing material should be used to repack the CT100 for shipment. Otherwise, the following steps should be taken:

1) Obtain a heavy-duty corrugated cardboard box at least 6 in. (15 cm) larger in each dimension than the equipment to be shipped to allow for protective cushioning material. The shipping carton should have at least 200 lb. (90.7 kg) test strength.

for shipment

2) Make sure the CT100 is turned off by setting the rear panel power switch to the OFF position.

3) Install the front panel cover.

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General Information

4) Wrap the CT100 in polyethylene sheeting to protect the case.

5) Place the CT100 in its soft case.

6) Cushion the CT100 on all sides with equal amounts of urethane foam or other firm packing

material so that the instrument is centrally situated in the shipping container and there is no free space for the CT100 to move about during shipment.

7) Seal the container with packing tape.

Mohr CT100 / CT100HF Operator's Manual 3

Safety Summary

The safety information presented in this brief summary is only intended for operators of the CT100 and CT100HF. Safety information relating to specific circumstances is present throughout this manual and is not necessarily present in this summary. Please read this manual in its entirety before using the CT100 and take note of safety information not included in this summary.

Terms in the manual

WARNING: Refers to conditions or practices that could result in personal injury or loss of life.

CAUTION: Refers to conditions or practices that could result in damage to this product or other products and in some cases could void the Warranty.

Terms on the product

DANGER

Indicates an injury hazard immediately accessible as you read the marking.

WARNING

Indicates an injury hazard not immediately accessible as you read the marking.

CAUTION

Indicates a hazard to property including the product.

Mohr CT100 / CT100HF Operator's Manual 5

Safety Summary

Symbols in the manual

Symbols on the product

Static

Any cable or wire can carry a significant static electric charge that could damage the sensitive electronics of the CT100/CT100HF. For this reason, it is essential to ground any cable or device about to be tested before attaching it to the front panel BNC or SMA adapter.

Fuses

There are no external fuses or breakers accessible to the user. However, there are two internal automatic thermal breakers that disconnect the power from the charger and battery to the rest of the system. These thermal breakers make an audible click when they actuate. One of the circuit breakers automatically resets after time. When this breaker cools, the CT100 can be restarted. There is also a breaker on the CT207 subassembly A4 charger board. If tripped, this breaker must be reset by taking the rear case off, locating the breaker assembly, and pushing its reset tab. The tab is located at the far end of the board, nearest to the fan.

charge

CAUTION: Failure to properly ground the cable / device under test prior to connecting it to the front panel connector, either directly or indirectly, could result in damage to the sampling electronics and will void the Warranty.

CAUTION: If the thermal breakers occasionally trip, the instrument should be evaluated by qualified service personnel for maintenance.

AC power source

The CT100 is intended to operate only from a 120 VAC or 240 VAC RMS power source using the CE- and UL-approved 24 VDC external power supply / adapter provided with the instrument.

6 Mohr CT100 / CT100HF Operator's Manual

Safety Summary

WARNING: Only use the power cord supplied with the instrument, and then only if the cord is in good condition. Refer all maintenance regarding the power supply or power cord to qualified service personnel.

CAUTION: Use of any power source other than the supplied external power adapter(s) could damage the instrument and may void the Warranty. Use only MOHR-approved accessories.

WARNING: To reduce the risk of electric shock, disconnect all external cables before connecting the 24 VDC external power supply.

Grounding the CT100

When the CT100 is connected to the external AC adapter, the CT100 chassis, front panel USB, screen, and controls are grounded through the grounding conductor of the power cord. To avoid electrical shock, it is essential that the protective ground connection is present when operating the unit under AC power. When disconnected from external power, the CT100 is floating relative to earth ground, unless one of the USB ports is connected to a grounded device. In this case, the ground of the USB device is common with the CT100 chassis, screen, and electronic controls. An isolated ground power supply is an optional accessory available upon request.

At all times, the front panel BNC connector is floating and is isolated by at least 500 VDC from the remainder of the CT100. This eliminates measurement errors caused by common-mode noise and slight ground-potential differences in the the cable / device under test. However, care should be taken with respect to electrical safety, as the front panel BNC shield is never safely grounded unless connected to a safely-grounded cable or device and can be considered a second live conductor if connected to a cable or device carrying a non-zero electrical potential relative to earth ground. This situation carries the risk of electric shock.

WARNING: The BNC connector shield represents a floating ground and is never safely grounded even with the use of a properly grounded AC adapter. Never use the CT100 to test any cable or device carrying a non-zero electrical potential relative to earth ground, as this could render an electric shock.

Danger arising from

When disconnected from the AC power adapter, the CT100 is no longer grounded unless connected to a grounded USB device. Because the BNC connector shield is floating relative to the remainder of the instrument, the BNC connector may be operating at an elevated voltage even when the AC adapter is connected. Therefore, the BNC connector should never be used to test any cable or device with an electrical potential relative to earth.

loss of ground

Mohr CT100 / CT100HF Operator's Manual 7

Safety Summary

WARNING: Upon loss of the protective-ground connection, all accessible parts, including the screen, knobs, and connectors, can render an electric shock.

Explosive atmospheres

Do not operate the CT100 in an explosive atmosphere unless your unit has been specifically certified for that condition. Explosive Atmospheres: MIL-STD 810G, Method 511.5, Procedure I (+55°C, sea level to 4600 m).

Do not remove

To avoid personal injury and risk of electric shock, do not open the CT100 case and do not operate unless the case is fully intact.

Connecting cables to the front panel BNC

To avoid damage to the CT100 and the very sensitive sampling electronics associated with the front panel BNC connector, do not connect it to any cable or device that can be driven by active circuitry or is subject to transient voltage spikes.

WARNING and CAUTION: The instrument should never be used to test any cable or device carrying live electrical signals, as this carries a risk of electric shock. This could also damage the sampling electronics and will void the Warranty.

CAUTION: Always properly ground the conductor(s) of any cable or wiring to remove any static charge prior to connecting it, either directly or indirectly through attachment to another cable, to the CT100's front panel BNC connector. Failure to do so can damage the instrument's sensitive sampling electronics and will void the Warranty.

covers

panels

Battery replacement and

The CT100 contains a 2700 mA·h internal battery pack consisting of 12 AA NiMH batteries, as well as a single lithium coin cell battery for the internal clock. Depending on the state or local jurisdiction, these batteries may require special disposal and/or recycling. Contact your local authorities for safe disposal in your area, or you may return them to MOHR Test and Measurement LLC for recycling.

8 Mohr CT100 / CT100HF Operator's Manual

disposal

Operating Instructions

Overview

Handling

The CT100 is designed to meet the rigors associated with normal instrument use both in the field and on the benchtop. Care should be taken to protect it from excessive mechanical shock, vibration, static electrical charges, and water hazards.

The CT100 front panel is protected from impact by a snap-on front cover, in which an optional small-format version of the Operator's Manual can be stored. The carrying handle rotates 360° and can be used to support the instrument for bench-top use.

The CT100 is not watertight and must be protected against water spray. If the unit is subjected to water spray, first turn off the unit with the battery-disconnect power switch on the rear panel and then drain all of the excess water from the case and allow it to dry completely.

As noted in the Safety Summary and elsewhere, the CT100 and CT100HF are sensitive to damage introduced by electrostatic discharge. Always properly ground the center conductor of a cable before attaching it, either directly or indirectly, to the front panel BNC or SMA connector. Failure to do so could damage the sampling electronics and void the Warranty.

The CT100 can be stored in temperatures of between -20°C to +60°C with or without a battery installed and can be operated from 0°C to +50°C.

Powering the CT100

The CT100 can be powered through the included 120/240 VAC (RMS) to 24 VDC external power adapter. This adapter has sufficient capacity to charge the internal battery from a dead battery state while the unit is under operation. The internal battery will allow the unit to operate using power conservation techniques for periods of at least 6 hours under typical use. Automatic power-down occurs after a variable amount of time of inactivity, selectable in software by the user. The screen also can be set to turn off after a set amount of inactivity. A heavily discharged battery will require 2.5 hours to reach full charge.

There is an option to use external, hot-swappable 14.4 VDC NiMH battery packs to power the CT100. These battery packs plug into the back panel external battery connector and can be charged while the CT100 is run on AC power. When connected, the device automatically powers off of the external battery pack until it is discharged. By default, the CT100 charges the internal battery until full before charging the external battery.

Mohr CT100 / CT100HF Operator's Manual 9

Operating Instructions

Fusing is internal and based on thermal reset switches and a manual-reset breaker located on CT207 subassembly A4. If one of these fuses trips, it may indicate that a hardware malfunction has occurred. Diagnostic steps should be taken to determine this.

Caring for the battery

The CT100 has an intelligent internal battery-charging circuit that dynamically determines the optimum charge rate and reverts to low-level trickle charge when the battery is fully charged. Charging is automatic and there are no charge-length restrictions.

The battery should be charged between 0ºC and +45ºC. Battery operation should be limited to between 0ºC and +50ºC. Batteries should be stored between -20ºC and +60ºC. If the battery pack is older, it may not show a 100% charge capacity even when the maximum battery charge is obtained.

CAUTION: Do not attempt to charge the battery pack below 0ºC or above +45ºC. Batteries should not be stored below -20ºC or above +60ºC.

Charging and power status

The CT100 operates from a 24 volt power adapter, internal battery pack, or an external battery pack. When plugged into an adapter, the CT100 will preferentially charge the internal battery pack over any connected external pack. When operating off of batteries, the CT100 will prefer to use an external battery pack over the internal battery pack.

When an external battery pack is connected and fully charged, the CT100 will return to tricklecharge the internal battery pack. However, as long as the internal pack remains fully charged, the CT100 will immediately switch to charging the external battery each time it is disconnected and a external pack is reconnected. In this fashion, a single CT100 can be used to charge several external battery packs in sequence.

In the Power menu, a submenu of the Main menu, the user can set power save and shutdown timers. Different time-out values can be set for when the CT100 is using the AC/DC converter or batteries. In power save mode, the screen goes blank and only enough power is used to monitor for user input. When input is received, the CT100 wakes back up. When a shutdown timer expires, the CT100 will turn off.

Also in the Power menu, the user can toggle the Charge External/Internal option to determine which battery pack has priority when charging. By default, the CT100 will charge the internal battery pack until it is full, then switch to charging the external battery pack. The functions of the external battery can be toggled on and off in the same menu. When off, external battery voltage and charge state will not be displayed.

A voltage readout can be turned off and on with the Power Display menu option in the Power menu. The battery will have its voltage displayed on the screen, along with the voltage from the 24 volt adapter if it’s attached. The color of the voltage text indicates the state of the power

10 Mohr CT100 / CT100HF Operator's Manual

Operating Instructions

source. If green, then that source is powering the CT100. If red, then that source is being charged.

Batteries and long-term storage

The CT100 has NiMH internal batteries. These batteries will drain if the CT100 is left in storage over long periods.

To preserve battery charge for as long as possible during storage, make sure the power switch on the back of the CT100 is set to the OFF position.

After several months of storage, the internal batteries may be completely drained. Allow up to 24 hours for the first re-charge of the CT100 after coming out of long-term storage.

Low battery

When a low battery condition is first encountered, the CT100 alerts the user with a red warning. An “Internal Battery Low” message appears when the battery percentage left drops below 20 percent.

Mohr CT100 / CT100HF Operator's Manual 11

Operating Instructions

Preparing to use the CT100

Before using the CT100, make sure you have read and understand the Safety Summary section and power requirements described in the previous sections. Then remove the front cover and turn on the power. You are ready to test cables using the most versatile and sophisticated stand-alone TDR on the market.

Front panel controls and connectors

The following numbered items describe the controls and connectors identified in the front panel diagram below (Figure 1).

Figure 1: Diagram of the front panel of the CT100 / CT100HF. Numbered controls and connectors are described in the text below.

1) POWER button. Pressing this button turns the instrument on when the main power switch on

the rear panel is in the ON position. Pressing the POWER button when the unit is on will turn the unit off. If you have any unsaved traces, the unit will verify if you really wish to power down. If the POWER button is held in for several seconds, the unit will turn off regardless.

2) H1 function button. Function depends on menu.

3) H2 function button. Function depends on menu.

4) H3 function button. Function depends on menu.

5) H4 function button. Function depends on menu.

12 Mohr CT100 / CT100HF Operator's Manual

Operating Instructions

6) MENU button. Push to display the top-level menu screen. Allows you to call up and navigate the CT100's internal menus. This button also activates on-screen help when held down while pressing other buttons.

7) VERTICAL POSITION knob. Controls the vertical position of the currently selected trace. Trace selection is controlled by the SELECT button (14).

8) VERTICAL SCALE knob. Controls the vertical scale, which is displayed on the bottom of the screen. This control modifies the appearance of all traces on the screen. The scale is expanded about the vertical center of the screen.

9) HORIZONTAL POSITION knob. Controls the horizontal position of the cursor and displayed trace relative to the start position of the cable scan or relative to the connection to the unit.

10) HORIZONTAL SCALE knob. Controls the horizontal scale of the displayed traces; this scale is displayed on the screen in either English or SI units. The scale is expanded about the active cursor.

11) BNC connector. This connects to the cable you wish to test. Be sure to properly ground the cable before connecting it to the BNC connector in order to prevent electrostatic damage to the CT100's sensitive sampling circuitry.

CAUTION: All static charge must be drained from the cable to be tested prior to connection to the BNC connector (11). This is done by shorting the center conductor of the cable to the sheath / ground return. If this procedure is not followed, the sampling electronics can be damaged and you will void the Warranty.

12) Host USB port. This USB (V1.1) connection can be used to interface to a client USB device such as a barcode reader, keyboard, or thumbdrive.

13) LIBRARY button. Opens the Library menu, which contains a database of prior named configurations and saved cable records (scans) and the records of known cable types.

14) SELECT button. Used to select between traces on the screen. It has no effect if there are no scanned traces loaded.

15) CURSOR button. This button is used to toggle between the two available cursors displayed on the screen. The distance, return loss, and other measurements between the two cursors can be displayed on the screen. If you press and hold the CURSOR button for one second, then release, any cursors not on the screen will be moved onto the screen.

16) SCAN button. Displays a specialized soft-menu that brings up the Scan and Trace menu. It lets you perform automated scans of the entire cable detected by the AUTOFIT button (17), a segment of cable defined by the cursors, or the current screen. It also contains the menus for saving, deleting, hiding, and performing mathematical operations on selected traces.

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Operating Instructions

17) AUTOFIT button. The AUTOFIT function displays the cable connected to the unit from the

BNC connection to the end of the cable terminated by either a short or an open or by the location of the last cursor position. This functionality allows the user to immediately display an entire cable, compressed to fit on the screen. The user can then position the active cursor over the location of interest and expand the scale to zoom in.

18) M-FUNC (multifunction) button. The function of the M- FUNCTION knob (19) is set by this

button. The current operation is displayed on the screen.

19) M-FUNCTION (multifunction) knob. This knob adopts the function selected through the use

of the M-FUNC button (18).

20) V1 function button. Function depends on menu.

21) V2 function button. Function depends on menu.

22) V3 function button. Function depends on menu.

23) V4 function button. Function depends on menu.

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Rear panel connectors and switches

The following numbered items describe the connectors and switches identified in the rear panel diagram (Figure 2).

Figure 2: Diagram of the rear panel of the CT100 / CT100HF. Numbered connectors and switches are described in the text below.

24) External 14.4 VDC battery pack connection. The CT100 provides the operator the ability to select whether the external battery or the internal battery is preferentially charged. By default, the internal battery is preferred for charging. In either case, the secondary battery will be charged when the preferred battery is detected to be at full charge.

25) 24 VDC power adapter plug. The provided 24 VDC AC adapter plugs into this port. Only MOHR-approved positive center tip, 24V adapters may be used.

26) Client USB connection. Allows the CT100 to be connected to a host computer for data transfer and PC control.

27) RJ-45 Ethernet port. This is a 10/100 Mb Ethernet port that can be used for data transfer and remote PC control.

28) Power switch. This is a manual ON/OFF power switch that turns the device off and prevents it from powering on.

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Operating Instructions

Setting up the CT100

Setting date and time

The date, time, and time zone must be accurately set for saved data in the CT100 to be correctly time-stamped.

Change the date and time by pressing the blue (MENU) button. This calls up the Main menu.

Select the Info menu option using one of the eight menu hot keys, as labeled on the screen. The Info menu appears.

Select the Time menu option. The Time menu appears.

Select the Set Time Zone menu option. A dialog box listing all time zones appears on the screen.

Use the M-FUNCTION knob to scroll through the list of time zones. Highlight the correct time zone.

Choose the Select menu option. The CT100 will prompt you to restart. After doing so, the CT100 will be set to the correct time zone. Note that daylight savings should be turned on, and it will automatically adjust for daylight savings on the correct dates.

After restarting the CT100, the time may already be correct, but if not, return to the Time menu by pressing the blue (MENU) button, selecting Info, then selecting Time.

Select the Time/Date menu option. A dialog box used to set the date and time appears. See the next section for methods of navigating and entering data into a dialog box.

Press the OK menu option when the correct time and date have been entered.

Navigating dialog boxes

Scroll through the different entry boxes with the M-FUNCTION knob. With an entry box selected, press the Keyboard menu option to call up an on-screen keyboard.

With the on-screen keyboard chosen, select the desired characters with the M-FUNCTION knob, pressing the Select menu option for each one. Get more character options by selecting the Shift menu option. Delete the character before the cursor with the Back menu option.

With the keyboard open, accept the current entry with the OK menu option or revert to the original entry with the Cancel menu option.

With the keyboard off the screen, select the OK menu option to accept all changes to the current dialog box and close the dialog box. Select the Cancel menu option to close the dialog box while canceling all changes.

With a USB keyboard attached, entries can be changed directly. Use the tab key to scroll down through entry boxes and hold down shift and press tab to scroll up through entry boxes.

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Use backspace to delete the character before the cursor and use the arrow keys to move the cursor left or right. Press Enter for OK or Escape for Cancel.

Scrolling dialog boxes

Some dialog boxes present a list of items to be selected. Use the M-FUNCTION knob to highlight individual items for selection, then use the Select option to choose the highlighted item. Where appropriate, multiple items can be marked for selection using the options on the right-side menu: Toggle Selected, Clear All, Mark All, and Toggle All. When an individual item is marked, a symbol will appear in the last column of the scrolling dialog box.

Display features

The CT100 screen holds a lot of useful information. Figure 3 shows some of the typical features you will encounter during testing. Many other features are available, however, and most of them are configurable by the user. These features are described in detail in the following sections.

Figure 3: Screenshot showing typical features of the CT100 during testing including dual cursor functionality, scale and Vp settings, and multiple measurements including absolute distance at the active cursor, relative distance between cursors, impedance at the active cursor, relative reflection coefficient between cursors, and return loss between cursors.

License codes

Each CT100 requires a unique license code to operate. Without the correct code, menus and buttons still function, but there will be no live trace displayed on the screen. The correct code for a particular device can be requested from MOHR Test and Measurement LLC. Installation instructions will be included with the license code.

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Operating Instructions

Depending on how it was purchased, the instrument may be supplied with either a 30-day demonstration license or permanent license. Current license information can be found by selecting the License Info option of the Info menu. A dialog showing license date and active features will appear. When the CT100 has a permanent license installed, appropriate options will be active. When the instrument has a demonstration license, the dialog will show a future license date and the instrument will provide appropriate warnings to the user as the expiration date gets closer. If your CT100 has a license with pending expiration and you are unsure how to upgrade to a permanent license, please contact MOHR Test and Measurement LLC.

Menu selections and function buttons

M-FUNC button

Used to switch between functions Shift (Trace), Change Vp (and Fine/Coarse Vp), and Smooth on the M-FUNCTION knob screen function indicator.

The M-FUNC button has no effect if another function has captured the M-FUNCTION knob (see descriptions of functions below).

SCAN button and menu

Use this button and the associated Scan and Trace menu to initiate and modify cable scans.

Save

Saves the selected trace to flash memory (scanned traces only).

Hide

Removes selected trace from screen but does not delete from flash disk.

Scan

Initiates scan.

Scan mode (Cursor/Screen/Custom)

Switches between scan modes. Screen mode saves the trace as seen on the screen. Cursor scans between cursors at the current horizontal resolution. Custom scans between cursors at a resolution selected by the Select Scan Depth menu item.

Add Scan Depth Config

Add a custom scan depth to memory. This option will create a custom scan depth, a horizontal resolution for custom scans. The name, resolution, and units of the scan depth can be configured.

Select Scan Depth

With custom scan mode selected, the next menu option shows the currently selected scan depth. This gives the resolution in distance per screen division that will be used in a scan.

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Select this menu option to change the scan depth to any of those created by the Add Scan Depth Config menu option.

Show Sel. Trace Only

Select this item to show only the selected trace on the screen. Select again to show all traces on the screen.

Math

The Math menu contains frequently used mathematical operations. The items in this menu are identical to those found in the Math menu available in the Main menu.

Set base (1)

Sets the currently selected trace as the base trace, used by other actions in the Math menu that operate on more than one trace, such as Difference.

Difference

Creates a new trace that is the difference between the base trace (see Set base above) and the currently selected trace.

1st derivative

Creates a new trace that is the first derivative of the currently selected trace.

FFT

Creates a new trace that is the Fast Fourier Transform of the currently selected trace, using the data that lies between the cursors. The FFT is transformed using settings from the FFT settings submenu.

FFT settings

Window

Selects the data window that is applied after padding the data but before the Fast Fourier Transform.

Size

Selects the size of the data window. The data bounded by the cursors is padded with stationary values to fill the window size.

S-Param

Creates a new trace that is the negative complex division of the currently selected trace by the base trace. This function only applies to Fast Fourier Transform traces and can be used to calculate the S11 parameter.

Phase

Creates a new trace that shows the phase angle of the currently selected trace. This operation only applies to Fast Fourier Transform traces and S-Param traces.

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Operating Instructions

Layer Peeling

Layer Peeling reduces multiple reflections in live or saved traces. These are reflections of the step pulse off of more than one impedance change. A trace when layer peeled is automatically set as a ZTrace.

The Layer Peeling system is highly dependent on where it starts. The user sets the start of layer peeling with the active cursor. Good results are only obtained when the start of layer peeling is set at 50 ohms.

SELECT button

The SELECT button switches which trace on-screen is the active trace.

AUTOFIT

Automatically adjusts the TDR resolution to fit an entire cable from beginning to end (identified by open or short termination) on the screen. Pressing the AUTOFIT button a second time while autofitting will put both cursors visibly on the screen. If the AUTOFIT button is held down for one second then released, the CT100 will vertically center the currently selected trace at the active cursor. More information can be found in the section describing the Vertical Correction menu below.

CURSOR

Toggles between cursors, making the active cursor inactive and the inactive cursor active. Pressing and holding the CURSOR button for one second then releasing will move any cursors not on the screen to the screen.

LIBRARY button and menu

Use this menu to access the user library of configurations, cable types, and cable records.

Add Custom Cable Type

Add a custom cable type to be loaded using the option Load Custom Cable Types (see below).

Load Custom Cable Types

Opens a scroll dialog filled with user-defined cable types. Using this dialog, the user can load the cable types, including associated settings such as Vp. Cable types are added to this scroll dialog using the Add Custom Cable Type option.

Configurations

Call up interface to load a saved configuration.

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Cable Types

Call up an interface to browse the library of known cable types, with the ability to load associated settings such as Vp.

Cable Records

Call up an interface to browse the library of known cables, with the ability to load associated settings such as Vp and also associated configurations that have previously been used to scan a given cable.

Save Configurations

Call up interface to save a user configuration.

Add Scan Depth Config

Add a custom scan depth to memory. This option will create a custom scan depth, a horizontal resolution for custom scans. The name, resolution, and units of the scan depth can all be configured.

Load Scan Depth Config

Select this menu option to change the currently selected scan depth to any of those created by the Add Scan Depth Config menu option. This scan depth will be used in subsequent custom mode scans.

MENU button and top-level menu selections

If no menu is displayed, MENU loads the main top-level menu. If the top-level menu is displayed, it closes the menu. If a submenu is displayed, it displays the parent menu. Toplevel menu selections are listed below.

Holding down the MENU button while pressing any button (or the M-FUNCTION knob) will display a help dialog for that button's current menu selection.

Cable length selection

Use this selection for changing the pulse period to look at different lengths of cable. A green “S,” “M,” or “L” appears near the upper right of the screen, depending upon which mode is selected. If the letter is green, the settings are saved; if it is red, it has not been saved; and if it is yellow, it is saving.

Short

Use this setting for accurate measurements of short cables of less than 200 feet in length.

Medium

Use this setting for measurements of medium cables of less than 1000 feet in length.

Long

Use this setting for measurements of long cables of less than 4000 feet in length.

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Operating Instructions

Display settings

Turn on-screen display items on or off using the soft-menu buttons to show or remove a variable. For some items, pressing the button once shows the display item and pressing it again hides the item. Asterisks (on the menu) will appear on the sides of displayed items. Some items may disappear automatically when scanned traces are selected.

Show Ohms/rho

This item toggles on or off the impedance display in Ohms and the reflectance display in millirho.

Show date/time

This item toggles the date and the time display on or off. The first setting shows both the time and date, the next shows only the time, the next shows only the date, and the last turns the on-screen display of date and time off.

Show distance

This item toggles showing the distance measurements including meters (or feet) and nanoseconds.

Show VSWR

This item toggles the VSWR and RVSWR displays on or off.

Change screen profile

This item switches between white, black, and slate grey color schemes.

Horiz./vert. ruler

This item toggles the horizontal and vertical measurement rulers on and off. The rulers make judging trace values simpler, but also take up a lot of screen area.

Noise value

This items toggles the display of a noise measurement. This is rarely needed except for troubleshooting and calibration checks.

Show scale values

This item toggles the horizontal and vertical scales on and off.

Show cursor/trace intersection

This item toggles an 'x' crosshair where the vertical cursor intersects the on-screen trace.

Show absolute/relative return loss (Decibels)

This item toggles the display of relative return loss at cursor.

Show temperature

This item toggles the temperature displays on and off. These temperatures are accurately measured on the (internal) analog board as a calibration reference. It also serves to display to the user when the device may be running at potentially high temperatures on critically sensitive electronic components.

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Show Temp Comp

This item toggles whether the status of the automatic temperature compensation is displayed on the screen.

Power menu

Use this menu to adjust the power save options, the power display, and the battery charging preference.

DC power save

This sets the inactivity timeout for power save mode while the device is running on its 24 VDC source.

DC shutdown

This sets the inactivity timeout before the device shuts down while running on its 24 VDC source.

Battery power save

This sets the inactivity timeout for power save mode while the device is running on battery power (either internal or external).

Battery shutdown

This sets the inactivity timeout before the device shuts down while running on battery power (either internal or external).

Power display

This selection shows or hides the on-screen power display.

Battery units

This selection toggles between voltage or battery voltage percent left.

Battery charge preference (charge internal/external)

This item overrides the automatic preference for the CT100 to charge the internal battery first. When selected, the CT100 will charge the external battery until full before switching to the internal battery.

Use external on/off

This toggles whether external battery information is displayed on the screen.

Connections

Use this menu to change the way the CT100 connects to external sources. This menu is important for setting up the CT Viewer™ software. Items within this menu need only be used if a CT100 is connected to a network via Ethernet.

Server select

This menu item creates a dialog box used to scroll through a list of CT Viewer™ connections. Chose a connection with the Select option and attempt to connect to it. If the connection succeeds, a message appears on the CT Viewer™ screen, and File->OpenTester will now show traces as stored on the connected tester. A connection can be deleted from the list using the Delete menu option.

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Operating Instructions

Add server

Add a new connection to the Server Select list. A dialog appears with three edit boxes. There is a Server Name for user reference. This has no bearing on the actual connection. Server Address and Port number define the TCP connection that will be used to connect to the CT Viewer™ server.

Push test

This item moves a single saved trace from the CT100 to a CT Viewer™ database.

Push all tests

This item moves all saved traces from the CT100 to a CT Viewer™ database.

Network settings

Configure the CT100's Ethernet connection.

Static network settings

This item brings up a dialog window used to modify the network settings. These settings only apply if DHCP is not set. The dialog box allows the user to change the following:

IP address

The static address of the tester in 4-number-dotted notation.

Netmask

The subnet mask for the tester.

Gateway (optional)

The gateway server for the tester.

Nameserver1 and 2 (optional)

DNS server the tester uses to resolve host names. Nameserver2 is used if Nameserver1 fails.

Any changes to the network settings require a reboot to take effect.

DHCP on/off

This item enables or disables the use of DHCP on the Ethernet connection. When enabled, the tester will attempt to acquire network settings from a DHCP server on the network. When DHCP is off, the tester will use the settings in the Network Settings dialog. To directly connect to a computer using a cross-over cable, DHCP must be disabled.

Show IP config

Displays current Ethernet configurations.

Web export on/off

This item will enable two Web pages, http://<CT100 IP address>>/www/trace.csv and http://<CT100 IP address>>/www/screenshot.bmp, that show the trace. The first shows it as text data, and the second as a screenshot. Access to the Web pages requires an Ethernet connection and the address of the CT100. This can be found with the Show IP Config item under the Network Settings menu.

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Measurement menu

Use this menu to change units, Vp control, and reflection coefficient calculation method.

Extra long mode

Extra long mode allows the CT100 to take traces out to more than 10000 meters (33000 feet). Extra long is not as usable as other cable length modes, and some features don’t work properly. It should only be used when necessary. When in extra long mode, the Cable Length menu option will change to reflect this. Selecting the cable length button will switch away from extra long mode.

Set cursor X pos.

Enter in a value for the cursor position and the cursor will move to that position for the selected trace. On a time domain trace, enter the value in current horizontal units. On a frequency domain trace, enter the value in MHz.

Fine/coarse Vp control

Enable or disable 6 digit (fine) Vp precision.

Units

Switch between meters and feet for horizontal measurements.

Vert. Ref. menu

This menu has various options for setting and configuring a vertical reference. Vertical reference uses scans of open and short signals to give improved vertical measurements. In general, a vertical reference is valid only in the configuration and at the temperature for which it was created.

Vert. ref. off/on

This menu option will toggle on and off a vertical reference as created using the Set Vert. Ref. option (see below).

Set vert. ref.

This option requires both open and short attachments for the CT100. The CT100 will automatically calculate a vertical reference and prompt for a required open or short. When a vertical reference is calculated and applied, vertical values — millirho and Ohms — are much more accurate than standard TDR measurements. The vertical reference process, however, can take some time to calculate and is only valid for the temperatures at which it was taken. Vertical references cannot be stored for use across multiple sessions.

When the setup is complete, a green vertical line will appear under the active cursor. Points to the right of this line will use the new vertical reference, while points to the left will use the standard vertical measurements. This is useful for setting up a vertical reference at the end of a cable that won’t have its impedance changed by an attached open and short. This will often cause a visible break in the trace.

Vert. ref. center imp.

By default, when vertical reference is on, the center impedance, or impedance at 0 millirho is taken to be 50 Ohms. This option lets you enter in a new value. Use this

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Operating Instructions

option to get accurate impedance measurements when using an impedance matcher.

Vert. ref. start

Set the start of the vertical reference to the cursor position. The green line that marks the beginning of the vertical reference will be moved to under the active cursor.

Vertical Corrections menu

This menu contains options for adjusting or correcting vertical measurement.

Adjust Ohms/(unit distance)

This tool can be useful when examining long cables. Select this option to make the M-FUNCTION knob change the Ohms-per-unit distance loss setting for a cable. When activated, the Ohms-per-unit distance tool will correct for resistive loss down the length of the cable. The correction always extends from 0 distance to a position that can be fixed using other menu commands below. When activated, the end position will be displayed on the screen in a distinctively colored vertical line. This correction requires accurate Vp measurements and accurate vertical measurements. It is therefore best used in conjunction with a vertical reference (see above).

This tool may also be used to estimate resistive loss in a cable by adjusting the value until the cable shows no upward or downward trend across its length.

Ohms/(unit distance) correct on/off

Toggle the application of the Ohms per meter correction, as described above. If the end point of the correction has not been set, then it will be set to the position of the active cursor.

Set Ohms/(unit distance) position

Set the position of the Ohms/(unit distance) position to that of the active cursor.

Adjust rho offset

When activated, the adjust rho offset option will change the M-FUNCTION knob to adjust the vertical offset. The blue M-FUNC indicator at the top of the screen will also change to show that the units are now in millirho. Turning the M-FUNCTION knob will directly change the vertical measurements at the cursor. Advanced operators can use the M-FUNCTION knob to manually set vertical measurements to a known value. The adjusted value is never saved; restarting the CT100 will cancel the adjustment. When this correction is in use, automatic temperature adjustment will not correct vertical readings. A message that rho measurements are being manually adjusted will appear near on-screen measurements. Changing the rho values will change all vertical measurements including impedance, return loss, voltage, standing wave ratio (VSWR), and relative reflection coefficient (RRC).

Cancel rho offset

Use this option to cancel a manual rho correction. Automatic temperature adjustment will resume auto-correction of the vertical measurements.

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Auto vertical correction on/off

Use this option to force an automatic vertical correction each time an adjustment for temperature occurs. Typically, the automatic temperature adjustment uses a table of known values to calculate an appropriate adjustment. This option causes the table to be ignored and a re-measurement of the vertical correction value. This option is now obsolete due to new automated temperature correction and will be removed in future versions.

Force vertical correction

This option forces the CT100 to perform an automatic correction of vertical measurements immediately. Holding down the AUTOFIT button for one second, then releasing it provides a shortcut to this option. This option is now obsolete due to new automated temperature correction and will be removed in future versions.

Envelope Plot

The Envelope Plot system can create captures of transients, min-max envelope traces, and trace density plots. It has three options.

Envelope Plot On/Off

This menu option enables or disables the feature. When turned on, the CT100 begins capturing trace data and displaying the envelope plot on the screen.

Reset

The reset option clears the captured trace data, clears the plot on the screen, and begins drawing a new plot.

Fill Mode On/Off

This menu option toggles between fill mode and density plot mode. In fill mode, the screen is filled in from the lowest value trace up to the highest value trace. This is useful for finding rare transients and for finding the minimum and maximum envelope of the trace. In density plot mode, each point on the screen is drawn in a different color based on how frequently the trace visits that point.

ZTrace

ZTrace transforms a time domain trace from reflection coefficient (millirho) to impedance (Ohms) in the vertical dimension. This works on saved or live traces.

Legacy Options

This submenu contains features from previous versions of the CT100 software.

Oversample on/off

When oversampling is turned on, the CT100 uses about 1.5 times oversampling when the horizontal scale is large. Oversampling can assist in finding subtle faults while using large scales but slows down the frame rate. An indicator appears onscreen whenever oversampling is turned on.

Oversampling must be turned off while the CT100 is being calibrated.

RRC method

This item toggles between how the relative reflection coefficient is calculated. Classic: The measurement is related to the input signal at the fault. 1502C: The

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Operating Instructions

measurement is scaled to the input signal at the beginning of the cable (as in the Tektronix® 1502C).

Diagnostics menu

Use this menu to obtain information on the software and hardware versions and to diagnose potential performance issues.

Analog

Run automated diagnostics on the analog trace acquisition circuit board. Results are displayed on-screen in a message box.

Database menu

This menu has tools for management of the internal database.

Clean shutdown

This option defragments the database, freeing up unused space, then turns off the CT100. For daily use this option is not necessary. Use clean shutdown only when the CT100 is plugged into a power supply. Do not shutdown the CT100 while a clean shutdown is in progress.

Main board

Access this submenu to run a variety of diagnostic memory tests.

Memory

Run automated diagnostics on the main circuit board's memory interface. Results are displayed on-screen in a message box.

GPIO

Run automated diagnostics on General Purpose IO pins connected to the main circuit board. Results are displayed on-screen in a message box.

Peripherals

Run automated diagnostics on main circuit board peripherals. Results are displayed on-screen in a message box.

Service diagnostics

For a full description of this menu, please see Appendix C: Operator Performance Check.

Operator performance checks

Horizontal scale check

Vertical position check

Noise check

Offset/gain check

Sampling efficiency check

Aberrations check

Risetime check

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Jitter check

RAM/ROM check

Front panel check

This item opens the front panel button and knob check screen. Hit each button once and turn every knob in each direction. Press the red power button to exit when finished.

Jitter

Jitter measures signal noise, timebase jitter, and sampling efficiency of the trace. These values are used as part of the calibration checkout for the CT100, and results of interest are explained in the manual section on calibration. A 36 in., 50 Ω test cable must be attached to the CT100 during the measurement.

Calibration menu

For a full description of this menu, please see Appendix D: Calibration Procedures.

CAUTION: Items within this menu should only be used upon calibration of a CT100 or to verify that a CT100 is calibrated properly. Incorrect or improperly set calibration values will corrupt trace data and may damage the unit.

Cable length selection

This item is identical to the Main menu item of the same name.

Manual calibration menu

The Manual calibration menu is for expert users only, and allows manual changes of calibration values that are meant to be adjusted automatically.

Cable length selection

This item is identical to the Main menu item of the same name.

Step pulse reference

Adjusts the fine timing of the firing of the step pulse.

Timebase DAC

Adjusts the maximum range of the fine timing of the sampler.

Hybrid reference

Adjusts the reference voltage as applied to the hybrid unit.

Clear temp lookup

Clears the internal records of temperature calibrations. Clearing these records will cause some interruption to operation as the CT100 self-calibrates for changing temperatures. Temperature lookup data must be cleared immediately after the CT100 has been calibrated.

Hybrid adjust on

Toggle temperature correction for the Hybrid Comp calibration setting.

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Operating Instructions

Hybrid adjust info

Show the correction rate and reference temperature for the Hybrid Comp calibration temperature adjustment.

Temperature adjustment

When temperature adjustment is on, the CT100 will correct measurements for temperature variations and the CT100 will from time to time pause to adjust to a new temperature. Temperature adjustment should be turned off when calibrating, except when setting horizontal calibration, in which case temperature adjustment should be turned on.

Vertical calibration

Vertical calibration dialog for all three cable lengths.

Driver start auto calibrate

Step-by-step process with on-screen directions.

Capacitive load auto calibrate

Step-by-step process with on-screen directions.

Resistive load auto calibrate

Step-by-step process with on-screen directions.

Horizontal calibration variables

This sets the cursor's position as the zero point for distance measurements. This is normally the first falling edge when nothing is connected to the front cable connector (second rising edge on CT100HF units).

Info menu

This menu provides more information regarding the instrument and its installed software.

License info

This option gives information about the license installed on the CT100, including the license date and enabled options.

License from USB

Use this option to load a license code from a USB flash drive. Detailed instructions will be provided with the license code.

Web update

When a CT100 is connected to the Internet, this item will automatically update the CT100 if newer software is available.

Enter license

As an alternative to loading a license code, it can be manually entered using this option. This is useful for operators who are unable to connect to a computer or use a flash drive.

Software version

Display software and firmware version information. This also serves to verify the communications links between the micro-controllers.

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Hardware info

Display hardware information.

Usage

Display usage stats (hours, scans, storage, etc.).

Time

This menu allows a user to change time and date settings.

Set time zone

Change the time zone. Requires a reboot for changes to take effect.

Daylight savings on/off

Set whether the CT100 will automatically adjust for daylight savings time on the appropriate dates. Requires a reboot for changes to take effect.

Time/Date

Set the current date and time.

Math

The Math menu contains frequently used mathematical operations. The items in this menu are identical to those found in the Math submenu of the Scan menu

Set base (1)

Sets the currently selected trace as the base trace, used by other actions in the Math menu that operate on more than one trace, such as Difference.

Difference

Creates a new trace that is the difference between the base trace (see Set base above) and the currently selected trace.

1st derivative

Creates a new trace that is the first derivative of the currently selected trace.

FFT

FFT settings

Window

Selects the data window that is applied after padding the data but before the Fast Fourier Transform.

Size

Selects the size of the data window. The data bounded by the cursors is padded with stationary values to fill the window size.

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Operating Instructions

S-Param

Phase

Creates a new trace that shows the phase angle of the currently selected trace. This operation only applies to Fast Fourier Transform traces and S-Param traces.

Layer Peeling

Test preparations

Velocity of propagation

Velocity of propagation (Vp), also sometimes abbreviated VoP or VP, is the measure of the velocity of an electrical signal within a cable expressed as a fraction of c, the speed of light in a vacuum. With the CT100, Vp can be set in ranges between 0.25 and 1.0. See Appendix F for cable types and their estimated Vp.

Change Vp

The current setting for Vp appears on the lower center of the screen. Press the M-FUNC button until the top-center information indicator reads “Vp.” If Fine Vp is enabled from the Measurement menu, two “Vp” indicators will be separately available. Coarse Vp allows for the modification of the first 3 significant digits and Fine Vp allows for the modification of the last 3 significant digits.

Turn the M-FUNCTION knob and the Vp value will change accordingly. Measurements and traces are automatically updated on the display to reflect the new Vp.

An accurate Vp is necessary for accurate cable length and distance-to-fault measurements. For cables of a known type, the Vp can be approximated by using the nominal Vp for that cable type.

The CT100 has a built-in library of cable types and their Vp values. See Cable library section below.

You can also measure the Vp by testing a known length of cable that is of the same type as the one you want to test. The method is described in the Find an unknown Vp section.

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Operating Instructions

Find an unknown Vp

This method is used to find the Vp for cables under test where the Vp is entirely unknown. It requires a sample cable that is of the same type that can be measured physically.

1) Measure the length of the test cable. Make sure the test cable is of the same type for which you need to find Vp. If there are any adapters used while connecting the cable, include their length in the measurement, or set one of the cursors at the end of the adapter before attaching the cable.

2) Attach the test cable to the CT100.

3) Press the AUTOFIT button. The CT100 will now show the beginning and the end of the test cable (Figure 4).

Figure 4: Screenshot showing AUTOFIT result. The cable end, in this case an open termination, has been found at 3.002 feet and the cable has been fit to screen.

4) Position the active cursor at the end of the test cable. Use the HORIZONTAL SCALE knob to zoom in on the end of the cable and get an accurate placement (Figure 5).

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Operating Instructions

Figure 5: Screenshot after the HORIZONTAL SCALE knob has been used to zoom in on the cable end for greater accuracy in determining Vp.

5) Adjust Vp until the CT100 distance measurement to the active cursor equals the physical measurement. The final Vp value is the true Vp value of the cable.

Temperature correction

The CT100 may take control of the trace from time to time in order to adjust to changes in internal temperatures. A notice will appear on the screen during the adjustment, which may take several seconds.

The device also adjusts for temperature at startup and when changing the cable length settings. At these times, the correction takes somewhat longer than during normal operation. The readout for temperature on the device screen also shows the last temperature at which the device performed a correction. This readout will turn red when the difference between the current temperature and the temperature of last adjustment is too great.

Cable test procedures

Distance to fault

1) Attach the cable to the BNC connector.

2) Set Vp to match the Vp of the attached cable.

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Operating Instructions

3) Press the AUTOFIT button. The CT100 trace is now scaled to show the entire cable from

beginning to end. See Figure 6.

Figure 6: AUTOFIT cable. The cable termination is an open.

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Operating Instructions

4) Position the active cursor on the reflection caused by the fault. Adjusting the vertical scale helps make cable faults more obvious, as in Figure 7.

Figure 7: After adjusting the vertical scale, the cable fault marked by the active cursor is more apparent.

5) Use the HORIZONTAL SCALE knob to zoom in on the fault to get a more accurate measurement. The distance measurement to the active cursor is the distance to the fault. See Figure 8.

Figure 8: A zoomed-in view of the cable fault in the previous figure, in this case a standard 50 Ω cable with a bad cut in the shielding.

36 Mohr CT100 / CT100HF Operator's Manual

Common types of cable faults

Open faults appear as a pulse upward in the trace (Figure 9):

Operating Instructions

Figure 9: An open cable fault. The step pulse is completely reflected by the open termination of the cable.

Short faults appear as a pulse downward (Figure 10):

Figure 10: A short cable fault.

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Operating Instructions

Faults that are a long distance from the CT100 will show shallow reflections that are very long because the length of cable attenuates the high frequencies necessary for precise fault localization and characterization (Figure 11). Position the active cursor at the beginning of the reflection where it first deviates from the straight line trace of the cable.

Figure 11: An open cable fault at 1000 ft demonstrates a long, shallow reflected rise caused by cable attenuation of high frequency components of the step pulse.

Faults with reactive components such as capacitance and inductance appear as either transient dips or exponential curves above or below the characteristic impedance of the cable depending on whether they are parallel with the conductor or represent a fault to ground.

Faults that are not opens and shorts may not appear at the end of the trace after pressing the AUTOFIT button, but can appear anywhere along its length.

Any fault is likely to reduce the pulse strength and change the pulse velocity. The accuracy of distance measurement of a fault that appears beyond another fault is reduced.

38 Mohr CT100 / CT100HF Operator's Manual

Operating Instructions

Return Loss=−20⋅log

∣∣

Reflection coefficient measurements

The reflection coefficient is the ratio of the signal reflected back from a point of interest to the signal going into it. It is also is a measure of the impedance change at that point in a cable.

Reflection coefficient is designated by the Greek letter ρ and is sometimes written as rho.

The CT100 lets you measure ρ three different ways:

The first method is the absolute reflection coefficient, which describes the total reflection to the point of the active cursor compared to the input signal from the pulser/sampler at the beginning of the cable.

The vertical scale reading at the bottom of the screen in mρ per division is always based off of the absolute reflection coefficient.

The second and third methods rely on the relative reflection coefficient, which is a measure of the signal reflected between two points in the cable. For the CT100 this is between the passive cursor and the active cursor. The CT100 has two ways to calculate the relative reflection coefficient:

1) In Classic mode, the measurement is related to the input signal at the fault. This mode is

the standard, most accurate way to measure the relative reflection coefficient and is the default mode.

2) In Tektronix 1502C mode, while the measurement is relative to the passive cursor, it is

scaled to the input signal at the beginning of the cable. This mode was included so that the CT100 could display reflection measurements that match those measured by the Tektronix® 1502C. However, it is less accurate in longer cables and after multiple faults, as it does not take into account intervening signal losses.

Return loss measurements

Return loss is another way of measuring impedance change in a cable. Return loss is given in decibels (dB) and is always calculated using the relative reflection coefficient. Return loss is related to reflection coefficient ρ by the formula:

The larger the fraction of energy in the reflected signal, the lower the numerical return loss value, so that an open or a short that returns 100% of the signal has a return loss of 0 dB.

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Operating Instructions

Ohms-at-cursor

The CT100 also displays the impedance in Ohms (Ω) at the cursor position. A reading before and after a reflection from a fault shows the impedance mismatch that could cause such a reflection.

Impedance measurements at the first fault in a cable are more accurate than impedance measurements at more distant faults.

VSWR

VSWR is voltage standing wave ratio. VSWR measures the ratio of the maximum-over-time amplitude of the nodes and anti-nodes of the standing wave off of a reflection. If there's no reflection, VSWR will be 1. If all energy is reflected, VSWR goes to infinity. VSWR is a unitless, scalar value.

The CT100 displays two different VSWR values. The first, labeled VSWR on-screen, will be calculated from the total reflection relative to the output impedance of the CT100 (50 Ohms). The second, labeled RVSWR, will be calculated from the reflection between the two cursors. In other words, VSWR is based on the millirho reflection coefficient, while RVSWR is based on the RRC, relative reflection coefficient calculation.

VSWR and RVSWR have a menu option to toggle the display of the values on-screen in the Display menu.

Relative distance measurements

The CT100 displays the absolute distance from cable start and also the relative distance from the passive cursor to the active cursor.

Note that Vp must be set accurately for the section of cable between the cursors for the CT100 to measure relative distance accurately. The pulse velocity of any part of the cable that is not between the cursors will not affect the measurement. To measure the relative distance between two points in a cable, do the following:

1) Move the active cursor to the beginning of the section to be measured.

2) Press the CURSOR button to switch cursors.

3) Move the newly active cursor to the end of the section to be measured.

40 Mohr CT100 / CT100HF Operator's Manual

Operating Instructions

4) The CT100 displays the distance measured between the two cursors as a “Δ” value below

the absolute distance measurement. See Figure 12.

Figure 12: A 50 Ω to 75 Ω BNC to SMA interconnect measuring approximately 3.8 cm and return loss estimated at 15.5 dB.

Scan a trace

The CT100 can scan and save a trace into memory. Saved traces can appear on the screen in addition to the live trace. New traces can be selected by repeatedly pressing the SELECT button, and traces can be adjusted vertically independent of other traces.

To scan a cable or cable segment, press the SCAN button to bring up the Scan and Trace menu, then choose the Scan option from the menu to begin the cable scan.

There are three main types of scans: Screen scans, Cursor scans, and Custom scans. Screen scans capture the live trace as it appears on the screen. Cursor scans capture the entire trace between the two cursors at the current horizontal resolution. In this way, long lengths of cable can be captured at high resolutions with a single scan. Custom scans scan between the cursors as well, but use a custom horizontal resolution that can be configured and saved. A scanned trace is created with a smoothing factor as set at the time of the scan. Cursor or Custom scans that cover a long distance at a high resolution may take a long time.

During a scan, a menu will appear with a Cancel option. Select Cancel to immediately abort the scan.

Select a trace

The CT100 always shows one trace on the screen in bold. This is the selected trace.

VERTICAL POSITION and VERTICAL SCALE knobs as well as the Save, Delete, Hide, and Math options on the Scan and Trace menu are all actions that only operate on the selected

trace, leaving other traces on the screen unchanged. Vertical measurements such as reflection coefficient, return loss, and impedance are always based off of the selected trace and may disappear if the cursor scrolls beyond a scanned boundary.

Mohr CT100 / CT100HF Operator's Manual 41

Operating Instructions

1) Press the SCAN button to bring up the Scan and Trace menu.

2) Press the SELECT button to change which trace is active. Figure 13 demonstrates this principle with three different traces.

Figure 13: Screenshots showing selection of (A) a live trace, (B) a scanned trace that has been translated vertically using the VERTICAL POSITION knob, and (C) a trace representing the difference between the two.

42 Mohr CT100 / CT100HF Operator's Manual

Operating Instructions

Store a trace

A scanned trace can be stored for later recall:

1) Press the SCAN button. The Scan and Trace menu appears.

2) Press the SELECT button until the saved trace to be stored is selected.

3) Select the Save option from the menu.

4) The CT100 requires a name for storage and will prompt you for one with a dialog box.

5) A dialog menu appears. Choose the menu option to show the on-screen keyboard.

6) Use the M-FUNCTION knob and the Keyboard menu to select letters and numbers. See

Figure 14. Also see Navigating dialog boxes on page 15 for more information on using the

Keyboard menu. Press the Select option to enter the highlighted letter into the name.

Figure 14: Saving a trace. The software keyboard is being used to enter a name for the scanned trace in red on the screen. Alternatively, an external USB keyboard or barcode reader can be used to enter information.

7) Press the OK option from the menu when finished.

The trace is now stored, and can be recalled later by name under Cable Records.

An FFT trace can also be stored with the same process. However, be sure to select the base trace scan, not the FFT trace, before storing.

Mohr CT100 / CT100HF Operator's Manual 43

Operating Instructions

Load a trace (cable records)

Cable records describe configurations used to test individual cables with the CT100. A cable record stores the Vp, tester configuration, and the scanned trace from a test of an individual cable. Use of cable records helps ensure that multiple tests of the same cable use the same tester configuration and Vp value. Cable records do not load calibration values but use the current set values.

A stored trace can be loaded back to the screen:

1) Press the LIBRARY button. The Library menu appears.

2) Select the Cable Records option. An interface appears for the selection of a stored trace.

3) Use the M-FUNCTION knob and the menu keys to select the trace to load.

4) Press the selected menu option to load the trace. See Figure 15.

The stored trace now appears on the screen. It can be selected and manipulated the same as any scanned trace.

Figure 15: Loading a trace. The loaded trace (bold) has been translated slightly upward using the VERTICAL POSITION knob in order to improve visualization.

44 Mohr CT100 / CT100HF Operator's Manual

Operating Instructions

When a previously stored FFT trace is loaded, the FFT trace is automatically re-calculated during loading. This calculation may take several seconds.

Storage space

The CT100 has a large storage space, capable of holding thousands of trace scans. However, with continued use, CT100 storage will eventually fill up. Periodically, an effort should be made to clear stored traces from the device and free up storage space.

Backing up traces

The CT100 ships with an installation CD for the CT Viewer™ software for Windows. Using either a USB or an Ethernet connection, the CT100 can transfer stored scans to CT Viewer™. These scans are then stored in the Windows computer for later retrieval, review, e-mail, and analysis. See the CT Viewer™ manual for details.

Deleting traces

Once scans are backed up to a computer, they can be deleted from the CT100 either through the CT Viewer™ software or directly as follows.

1) Press the LIBRARY button to open the Library menu.

2) Select Cable Records. A scroll dialog appears, showing all saved trace scans.

3) Highlight specific traces for deletion using the Toggle Selected option or select them all with the Mark All option.

4) Select the Delete option. You will have to confirm the deletion.

Freeing up space

Deleting traces is the first step to clearing disk space, but the space is not freed until a clean shutdown is ordered from the Power Button menu.

1) Press the blue MENU button. The Main menu appears.

2) Select Diagnostics. The Diagnostics menu appears.

3) Select Database. The Database menu appears.

4) Select Clean Shutdown. The CT100 will now free up space that was used by deleted traces. Do not turn off the CT100 when using clean shutdown. The CT100 will shut itself down when it is safe to do so.

CAUTION: Switching off power during a clean shutdown could damage the instrument.

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Operating Instructions

View the difference between traces

1) Press the SCAN button. The Scan and Trace menu appears.

2) Press the SELECT button repeatedly until the first trace of interest is selected.

3) Select the Math option from the Scan and Trace menu and choose Set Base. The selected trace is now a base trace for further Math functions.

4) Press the SELECT button again until the second trace is selected.

5) Select Difference from the Math menu. A new trace is created that displays the difference between the base trace and the selected trace. See Figure 16.

Figure 16: Difference trace. The bold trace is created by subtracting the bottom (live) trace from the top trace.

46 Mohr CT100 / CT100HF Operator's Manual

Operating Instructions

View a first derivative of a trace

The CT100 can perform a wide range of mathematical transforms of on-screen traces, both in static and real-time forms. The following example demonstrates the use of the first derivative plot.

1) Press the SCAN button. The Scan and Trace menu appears.

2) Press the SELECT button until the trace of interest is selected.

3) Select the Math option from the Scan and Trace menu. The Math menu will appear.

4) Select 1st Derivative from the menu.

5) A new trace is created that displays the first derivative of the base trace. See Figure 17.

Figure 17: First-derivative plot (top) of an on-screen trace (bottom). A wide range of mathematical transforms can be easily implemented.

View a Fast Fourier Transform of a trace

1) Select the live trace with the SELECT button.

2) Use the CURSOR button and the HORIZONTAL POSITION knob to set the boundaries for

the FFT with a cursor at either end.

3) Press the SCAN button to open the Scan menu.

4) Select the Math menu option to open the Math menu.

5) Select the FFT menu option. The CT100 will now take a high resolution scan of the live

trace between the cursors, then convert the scan into an FFT plot. This may take some time.

Mohr CT100 / CT100HF Operator's Manual 47

Operating Instructions

FFT traces can be stored and loaded, just like normal scanned traces. When storing an FFT trace, be sure to select the base scan first, not the FFT trace. When the trace is reloaded, the CT100 will take a few seconds to recalculate the FFT trace.

View S-Param trace

The S-Param trace shows the result of complex division of one FFT trace by another. When a reflected short or open waveform at the test plane is chosen as the denominator and the waveform from the device-under-test (DUT) is chosen as the numerator, this feature will produce uncorrected S11 and S22 S-parameters of a two-port device-under-test (e.g., cable or connector), which is equivalent to frequency-specific return loss. When used properly, the SParam waveform can provide you with a quick, semi-quantitative estimate of frequencyspecific return loss between cursors.

1) Press the SCAN button. The Scan menu will appear.

2) Choose the Math menu option. The Math menu will appear.

3) Select the first FFT of interest by pressing the SELECT button repeatedly.

4) Choose the Set base menu item to set the selected trace as the base trace.

5) Select the second FFT of interest by pressing the SELECT button repeatedly.

6) Choose the S-Param menu item. A new trace will be created that shows the selected trace divided by the base trace.

Calibrated S-Param trace

The Calibrated S-Param feature is a planned software upgrade that may be included with your instrument. This feature uses precision open, short, and 50 ohm load (OSL) measurements to correct for systemic errors in the pulsing and sampling electronics, producing a more accurate S11 result than the standard S-Param trace. A menu with four options will be available as a submenu of the Math menu. These options will allow the selection of individual FFT traces for use as the three calibration measurements. Each of the three measurements must be set before the fourth option can be used on a fourth FFT trace, representing the target trace for the S11 measurement.

Remote control

Using the accompanying CT Viewer™ software, the CT100 can be operated by remote control. The remote control system allows the operator to manipulate traces and store movies of traces over time. Remote control only functions over Ethernet connections. It does not work when the CT100 is connected by USB only.

The CT100 must first connect to the CT Viewer™ software over Ethernet. Please see the Connecting the CT100 to the CT Viewer™ software over Ethernet section of the CT Viewer™” manual.

48 Mohr CT100 / CT100HF Operator's Manual

Operating Instructions

Once a connection has been established, CT Viewer™ can be granted remote control over the operation of the CT100. Please consult the CT Viewer™ manual for details about starting remote control and manipulating a remote trace.

Cable type

The CT100 has a library of common cable types. Vp for these cable types can be loaded from the library.

Load a cable type's Vp

1) Press the LIBRARY button. The Library menu appears.

2) Select Cable Type from the menu. An interface appears that allows you to scroll through the cable types with the M-FUNCTION knob.

3) Select the desired cable type and press OK. Vp is now set to the value for that cable type.

User editable cable types

The CT100 is also able to save and load custom cable types.

1) Press the LIBRARY button to access user editable cable types. There are two new items on the Library menu: Add Custom Cable Type and Load Custom Cable Type.

2) When Add Custom Cable Type is selected, a window appears for entering a cable type name, a Vp for pulse velocity, and an expected impedance. When the window first appears, Vp will be set to the current system Vp, while impedance defaults to 50 Ohms.

The other menu option, Load Custom Cable Type, opens a window with all of the added user types available for selection. Use the M-FUNCTION knob and the Select menu option to load a particular cable type. When selected, the operating Vp is changed to match the selected cable type.

The user-added cable types are stored and accessed separately from the standard cable types, which are still available through the Cable Types menu item.

Measurement

Change units

Horizontal measurements can be displayed in physical meters, centimeters, feet, inches, or yards; and nanoseconds.

1) If there is a menu on the screen, press the MENU button until no menu is on the screen.

2) Press the MENU button. The screen will display the Main menu.

3) Select Measurement from the menu. The Measurement Settings menu appears.

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Operating Instructions

4) Select Units meters (feet) to switch between the different unit options.

All measurements and all traces are immediately updated to reflect the unit change. Nanoseconds are displayed separately.

Fine Vp control

By default, the CT100 displays 3 decimal places for Vp; however, the CT100 can display 6 decimal places for Vp when extremely precise distance measurements are desired.

1) If there is a menu on the screen, press the MENU button until the menu disappears.

2) Press the MENU button. The screen will display the Main menu.

3) Select Measurement from the menu. The Measurement Settings menu appears.

4) Select Vp 3(6) Sig Figs from the menu. The CT100 will now display 6 decimal places for the Vp readout on the screen when Vp 6 Sig Figs is shown on the menu.

5) When the CT100 is in Fine Vp mode, a new function, Fine Vp, is added to the M- FUNCTION knob. When the M-FUNCTION knob is set to Fine Vp, turning the knob will change the Vp value by the millionths. The Vp value can be changed by thousandths as normal by setting the M-FUNCTION knob to the Coarse Vp function.

Relative reflection coefficient

The CT100 measures the relative reflection coefficient between cursors. When the two cursors of the CT100 are positioned on either side of a change in impedance, this measurement is the reflection coefficient for that change. By default, the value is displayed in Classic mode, displaying the true reflection coefficient relative to the signal at the input of the reflection. The CT100 can also measure in 1502C mode, which displays a reflection coefficient relative to the signal at the input of the cable.

1) If there is a menu on the screen, press the MENU button until the menu disappears.

2) Press the MENU button. The screen will display the Main menu.

3) Select Measurement from the menu. The Measurement Settings menu appears.

4) Select RRC Method from the menu. This will toggle the CT100 between the Classic RRC calculation and the 1502C calculation as displayed on the screen.

Vertical reference

Use the vertical reference system to increase the accuracy of vertical measurements, including impedance, reflection coefficient, and return loss.

1) From the Main menu, go to the Measurement menu.

2) On the right side, an option for Vert. Ref. Appears. Select this. The Vert. Ref. menu appears.

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Operating Instructions

3) Position the active cursor at the left most position where the Vert. Ref. should apply.

Typically, this will be the position where you will apply the open and short attachments in step five. This position can be changed after the setup.

4) Select the Set Vert. Ref option.

5) A set of terminators, both open and short, are included with the CT100 for calibration

purposes. Attach these terminators to the CT100 when prompted to do so. (For the CT100, CT100-AC-IBMM is used to open the shorting BNC.) For the short condition, shorting caps are provided for both the CT100 with a shorting BNC and the CT100 with SMA connections.

When the reference measurement is finished, cursor measurements will now appear in blue, and a line saying using vert. ref. will appear underneath.

A green line will appear under at the position of the active cursor (see step 3 above). Vertical reference is applied to all points to the right of the green line. Standard vertical measurements are used for all points to the left of the green line. The position of this line can be changed with the Vert. Ref Start menu option.

By default, the impedance value at 0 millirho is taken to be 50 Ohms. This value can be changed with the Vert. Ref. Center Imp. menu option.

The CT100 is now configured for impedance measurements better than 2% across a wide range of impedances.

The menu option at the top of the right hand side can be used to toggle the vertical reference on and off as needed for a given cable length setting.

Cable resistance correction

The CT100 also has a system for correcting for resistance in cables.

Under the Measurement menu, there is an item to set Ohms per unit length and another item to toggle the correction on and off. The calculations of this feature assume a linear serial resistance to an attached cable and no other loss. Use with caution.

1) From the Main menu, go to the Measurement menu.

2) Select Vertical Correction. The Vertical Correction menu will appear.

3) Select Adjust Ohms/m.

4) Select Ohms/m correct off to turn on the correction. The first time you turn on the

correction, the end point will also be moved to the location of the active cursor. Subsequently, the end point of the correction can be moved by choosing the Set Ohms/m position menu option.

5) Use the CURSOR button to switch to the other cursor.

Mohr CT100 / CT100HF Operator's Manual 51

Operating Instructions

The ohms per unit length correction adjusts impedance and other vertical values from the zero position out to the position endpoint. The endpoint will appear as a distinctively colored vertical line .

The current Ohms per unit length setting now appears in the M-FUNC indicator at the top of the screen.

6) Rotate the M-FUNCTION knob to change the setting. Use the Ohms per unit length

toggle menu option to turn the correction on or off.

Changing the Ohms/m setting will change the slope of the cable’s trace, and consequently the impedance readings for all points on the cable’s trace and beyond. The effect and accuracy of the Ohms per unit length value is dependent on the value for pulse velocity.

Use this correction to make more accurate impedance measurements on a length of cable. One technique is to adjust the correction until the cable is as flat as possible. Another is to attach a known impedance reference, such as a resistive terminator, to the cable and adjust the Ohms per unit length correction until the measured impedance reads the correct value.

Configurations

The CT100 allows the user to save configurations with a name. A saved configuration stores the values of all CT100 settings. A configuration can be called up by its name, restoring all settings to the values saved in that configuration. By default, the configuration load screen is displayed at start up for easy loading of configurations.

Save configurations

1) Press the LIBRARY button. The Library menu appears.

2) Select the Save Config item. The CT100 will prompt you for a configuration name, then saves the configuration. See Navigating dialog boxes on page 15 for information on using the Keyboard menu.

Load configurations

1) Press the LIBRARY button. The Library menu appears.

2) Select the Configurations menu item. The Configurations dialog box appears.

3) An interface that lets you scroll through the configurations with the M-FUNCTION knob is displayed.

4) Press OK on the menu when the appropriate configuration is highlighted. All settings saved in that configuration are automatically restored. Measurements and traces are updated to reflect the new settings.

52 Mohr CT100 / CT100HF Operator's Manual

CT Viewer

The CT Viewer™ host computer software allows users of the MOHR CT100 and CT100HF Metallic Time-Domain Reflectometer (TDR) to transfer, view, and manipulate the cable scans that have been saved on their instruments. This software package allows the user to select scans from a stored database that can contain thousands of scans and compare, subtract, or find the first derivative of any of the traces.

This software package will also allow the user to create reports and print plots that can be imported into MS Word or other word processing or report creation software to create files of traces suitable for transfer to others and to load trace files created by others.

For information on installing and using CT Viewer™, please see the CT Viewer™ manual.

™

Mohr CT100 / CT100HF Operator's Manual 53

Options and Accessories

Options

Model CT100 — standard pulser-sampler (100 ps system risetime, 20-80%) Model CT100HF — high-frequency pulser-sampler (60 ps system risetime, 20-80%)

Accessories

Standard accessories (CT100)

Precision BNC 36 in. 50 Ω Test Cable CT100-AC-W536 50 Ω BNC Terminator CT100-AC-ER50 BNC Capacitive Terminator CT100-AC-C001 Connector, BNC female to female CT100-AC-IBFF Connector, BNC male to BNC male CT100-AC-IBMM BNC Shorting Cap CT100-AC-IBS 24 VDC External Power Supply CT100-AC-PS Operator's Manual, Printed CT100-M-OM-xxx* CT Viewer™ Manual, Printed CT100-M-CTVM-xxx* CT Viewer™ Installation CD, w/ Digital Operators

and CT Viewer™ Manuals CT100-S-CTVOM-xxx* Soft Carrying Case CT100-AC-CS NIST-Traceable Calibration with Certificate CT100-AC-NISTCC

Standard high-frequency accessories (CT100HF)

Precision SMA 36 in. 50 Ω Test Cable CT100-AC-W536S 50 Ω SMA Terminator CT100-AC-ER50S BNC Capacitive Terminator CT100-AC-C001 Connector, SMA male to male CT100-AC-ISMM Connector, BNC male to BNC male CT100-AC-IBMM Connector, SMA male to BNC female CT100-AC-ISMBF Connector, BNC male to SMA female CT100-AC-IBMSF SMA Shorting Cap CT100-AC-ISS 24 VDC External Power Supply CT100-AC-PS Operator's Manual, Printed CT100-M-OM-xxx* CT Viewer™ Manual, Printed CT100-M-CTVM-xxx*

* xxx applies to revision number. Accessory part number is incremented per revision.

Mohr CT100 / CT100HF Operator's Manual 55

Options and Accessories

CT Viewer™ Installation CD, w/ Digital Operators and CT Viewer™ Manuals CT100-S-CTVOM-xxx*

Soft Carrying Case CT100-AC-CS NIST-Traceable Calibration with Certificate CT100-AC-NISTCC

Optional accessories (CT100 / CT100HF)

External Battery Pack (2700 mA·h) CT100-AC-B2700E 24 VDC Isolated External Power Supply CT100-AC-PSI Hard Carrying Case CT100-AC-CH Connector, BNC female to Dual Banana Plug CT100-AC-IBFDBAP Connector, BNC male to Dual Binding Post CT100-AC-IBMDBIP Connector, BNC female to Hook-tip Leads CT100-AC-IBFL Connector, BNC male to N female CT100-AC-IBMNF Connector, BNC female to N male CT100-AC-IBFNM Connector, BNC female to UHF male CT100-AC-IBFUHFM Connector, BNC female to UHF female CT100-AC-IBFUHFF Connector, BNC female to Type F male CT100-AC-IBFFM Connector, BNC male to Type F female CT100-AC-IBMFF Adapter 50 Ω to 75 Ω CT100-AC-I5075 Adapter 50 Ω to 93 Ω CT100-AC-I5093 Adapter 50 Ω to 125 Ω CT100-AC-I50125 Small Form Factor Keyboard CT100-AC-KBD Clear Screen Protector Pack CT100-AC-SPC Anti-Glare Screen Protector Pack CT100-AC-SPAG BNC RF Adapter Kit CT100-AC-BNC SMA RF Adapter Kit CT100-AC-SMA Impedance Matching Kit 75,93,125 Ohm (BNC) CT100-IK-BNC Impedance Matching Kit 75,93,125 Ohm (SMA) CT100-IK-SMA Impedance Matching Adapter, 75 Ohm (BNC) CT100-AC-I5075-BNC Impedance Matching Adapter, 93 Ohm (BNC) CT100-AC-I5093-BNC Impedance Matching Adapter, 125 Ohm (BNC) CT100-AC-I50125-BNC Impedance Matching Adapter, 75 Ohm (SMA) CT100-AC-I5075-SMA Impedance Matching Adapter, 93 Ohm (SMA) CT100-AC-I5093-SMA Impedance Matching Adapter, 125 Ohm (SMA) CT100-AC-I50125-SMA

Service accessories (CT100 / CT100HF)

Technical Service Manual, Printed CT100-M-TSM-xxx* Technical Service Manual, Digital w/ CT Viewer™ Installation CT100-S-CTVTSM-xxx*

* xxx applies to revision number. Accessory part number is incremented per revision.

56 Mohr CT100 / CT100HF Operator's Manual

Appendix A:

Electrical specifications

Specifications

Characteristic Specification Notes

Reflected risetime, CT100 10-90% 150 ps typ, 200 ps max 10 to 90%, into 50 Ω terminator

Reflected risetime, CT100 20-80% 100 ps typ, 150 ps max 20 to 80%, into 50 Ω terminator

Reflected risetime, CT100HF 10-90% 100 ps typ, 130 ps max 10 to 90%, into 50 Ω terminator

Reflected risetime, CT100HF 20-80% 60 ps typ, 90 ps max 20 to 80%, into 50 Ω terminator

Jitter 15 ps max (peak-to-peak) < 1 ps rms typ.

Output impedance 50 Ω ±2%

Pulse amplitude 295 ±5 mV Into 50 Ω load

Pulse width Adjustable from 1 to 100 μs

Pulse repetition time Adjustable from 4 to 125 μs

Sequential sampling rate Adjustable from 8 to 250 kHz

Vertical scale 0.5 mρ/div

Vertical accuracy ±3% full scale

Vertical position Any trace point is movable to the

center of the screen.

Sampling efficiency, CT100 50 to 90% into 50 Ω terminator

Sampling efficiency, CT100HF 45 to 90% into 50 Ω terminator

Noise ±5 mρ peak-to-peak

Input susceptibility ±1 A Into diode clamps

Distance cursor resolution 1/45 of one major division

Cursor readout range ≤ -0.3m (-1 ft) to > 10000 m (33000 ft)

Cursor readout resolution 0.0002 m (0.0007 ft)

Distance measurement accuracy < 1 cm (0.3 in.) or ±0.5% of

measurement plus uncertainty in Vp, whichever is greater

Impedance readout range <1 Ω to >1.5 kΩ

Impedance resolution 3 significant digits

Impedance accuracy ±10%, relative measurement ±2% < 1% or 1 Ω typ.

Horizontal scale 0.01 m/div (0.03 ft/div) to ≥ 61 m/div

(200 ft/div) (variable with pulse width)

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Appendix A: Specifications

Characteristic Specification Notes

Horizontal range < 0 m to > 1000 m (3300+ ft)

Horizontal position Any distance to full scale can be

moved on the screen.

Vp range 0.250000 to 1.000000

Vp default resolution 0.001

Vp fine resolution 0.000001

Vp default accuracy ±0.1%

Vp fine accuracy ±0.0001%

USB host port USB 1.1 The USB host connections on the

front of the instrument are powered. The host supplies up to 500 mA per channel to power any device connected. The USB host is isolated from the analog board by 500 V.

USB client port USB 1.1 The USB client is isolated from

the analog board by 500 V.

Ethernet port The instrument includes a 10/100mbps

Ethernet port for network communication.

DC power supply 24 VDC, 2.5A, positive tip. Use only

the MOHR-approved power supply.

Battery pack 12 NiMH AA cells, fused at 2.5 A Pack may wear out over time.

External battery pack 12 NiMH AA cells, optional This pack is identical to the

Battery operation time > 6 hours. Power save options may

extend operating time.

Battery charge time 2.5 hours from fully discharged state The instrument has smart

Overcharge protection Charging discontinues once full charge

is attained.

Discharge protection Instrument turns off prior to battery

damage

Charge capacity 2.7 Amp-hours (nominal-new)

The Ethernet port is isolated from the analog board by 500 V.

The DC power supply is isolated from the analog board by 500 V.

internal pack and may be charged by the internal battery charger.

18V full charge down to 12 V battery low, 35% duty cycle.

charging circuitry, and can charge either the internal or an authorized external battery.

Software shutdown when battery is low.

58 Mohr CT100 / CT100HF Operator's Manual

Mechanical specifications

Weight

Without cover 2150 g (4.740 lb.)

With cover 2323 g (5.121 lb.)

With cover and ext. battery pack 2778 g (6.124 lb.)

Dimensions

Height 10.9 cm (4.28 in.)

Width w/ handle 29.2 cm (11.50 in.)

Width w/o handle 26.2 cm (10.30 in.)

Depth w/ cover 17.5 cm (6.90 in.)

Appendix A: Specifications

Depth, handle extended 27.9 cm (11.00 in.)

Environmental specifications

Temperature

Operating temperature 0°C to +50°C

Non-operating temperature -20°C to +60°C

Mohr CT100 / CT100HF Operator's Manual 59

Appendix A: Specifications

Certifications and Compliances

The CT100 and CT100HF comply with all applicable EU directives.

FCC Compliance

CT100 and CT100HF emissions comply with FCC Code of Federal Regulations 47, Part 15, Subpart B, Class A Limits.

60 Mohr CT100 / CT100HF Operator's Manual

Appendix B: Subassembly Drawings and Parts List

Subassembly

The following drawings of the CT100 and associated mechanical and electrical subassemblies are included on the next six (6) pages:

1) CT100 full assembly, demonstrating the entire CT100 with all included subassemblies — see Figure 18.

2) CT207 power and charger subassembly — see Figure 19.

3) CT208 analog / digicomp subassembly — see Figure 20.

4) CT209 back panel subassembly — see Figure 21.

5) CT290 front panel subassembly — see Figure 22.

6) CT290HF front panel subassembly — see Figure 23.

drawings

Mohr CT100 / CT100HF Operator's Manual 61

Appendix B: Subassembly Drawings and Parts List

Figure 18: CT100 complete mechanical and electrical assembly.

62 Mohr CT100 / CT100HF Operator's Manual

Appendix B: Subassembly Drawings and Parts List

Figure 19: CT207 (power) subassembly.

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Appendix B: Subassembly Drawings and Parts List

Figure 20: CT208 (analog) subassembly.

64 Mohr CT100 / CT100HF Operator's Manual

Appendix B: Subassembly Drawings and Parts List

Figure 21: CT209 (back panel) subassembly.

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Appendix B: Subassembly Drawings and Parts List

Figure 22: CT290 (front panel) subassembly.

66 Mohr CT100 / CT100HF Operator's Manual

Appendix B: Subassembly Drawings and Parts List

Figure 23: CT290HF (front panel) subassembly.

Mohr CT100 / CT100HF Operator's Manual 67

Appendix B: Subassembly Drawings and Parts List

Parts list

Subassembly Item Part No Qty Description

Front Panel CT 290 LCD display, front control board, switches, and knobs

1 A3 1 Front panel switch board, encoders and controller 2 A5A2 1 Subassembly, Power switch 3 A7 1 Video assembly board 4 A7A2 1 Sharp LCD 4.3” diagonal screen 5 CT123-L 1 Front panel bracket left side 6 CT123-R 1 Front panel bracket right side 7 CT124 1 Display backplane bracket 8 CT128 1 Ferrite support bracket 9 CT131 1 ESD FP bracket 10 CT132 1 ESD VM bracket 11 CT133 1 ESD VD bracket 12 CT213 1 Lexan LCD screen display cover 13 CT219 5 Control knobs – 6mm shaft, flat sided 14 CT228 1 Display impact absorbing gasket – PORON 0.060” 15 CT293 1 Front panel assembly with switch panels and front decals 16 CT295 1 ESD Module 17 CT302 4 Screw #8-32 X 3/8” SS cross top pan head 18 CT304 12 Screw plastite, # 2-28 X 1/4L 19 CT313 5 Screw, pan head, cross top, 6-32x1/4l SS 20 CT319 3 Screw plastite, # 2-28 X 1/2L 21 CT322 2 Standoff, round, thru-hole, #2 X 3/16 L 22 CT333 5 Washer, internal tooth # 6 23 CT336 1 Standoff, round, thru-hole, AL, #2 X 3/16L 24 CT338 1 Belleville disc spring 25 CT339 4 Washer, internal tooth #8 26 M1 1 BNC assembly 27 M2 1 Ferrite EMI filter 28 W2W7C1 1 Digicomp-video PCB FFC 40 pin flat-flex 0.5mm space 29 W3W3C1 1 Front panel to 4 button PCB cable 30 W3W3C2 1 Front panel to 5 button PCB cable 31 W3W3C3 1 Front panel to 6 button PCB cable 32 W5W2W7W3C1 1 Digital power assembly cable

High-Frequency Front Panel

CT 290HF LCD display, front control board, switches, and knobs

1 A3 1 Front panel switch board, encoders and controller 2 A5A2 1 Subassembly, power switch 3 A7 1 Video assembly board 4 A7A2 1 Sharp LCD 4.3” diagonal screen 5 CT123-L 1 Front panel bracket left side 6 CT123-R 1 Front panel bracket right side 7 CT124 1 Display backplane bracket 8 CT128 1 Ferrite support bracket 9 CT131 1 ESD FP bracket 10 CT132 1 ESD VM bracket 11 CT133 1 ESD VD bracket 12 CT213 1 Lexan LCD screen display cover 13 CT219 5 Control knobs – 6mm shaft, flat sided 14 CT228 1 Display impact absorbing gasket – PORON 0.060” 15 CT233 1 Case, front bushing 16 CT293HF 1 Front panel assembly with switch panels and front decals 17 CT295HF 1 ESD Module 18 CT302 4 Screw #8-32 X 3/8” SS cross top pan head 19 CT304 12 Screw plastite, # 2-28 X 1/4L 20 CT313 5 Screw, pan head, cross top, 6-32x1/4l SS 21 CT319 3 Screw plastite, # 2-28 X 1/2L 22 CT322 2 Standoff, round, thru-hole, #2 X 3/16 L 23 CT333 5 Washer, internal tooth # 6 24 CT336 1 Standoff, round, thru-hole, AL, #2 X 3/16L 25 CT338 1 Belleville disc spring 26 CT339 4 Washer, internal tooth #8 27 M2 1 Ferrite EMI filter 28 M5 1 SMA bulkhead connector 29 W2W7C1 1 Digicomp-video PCB FFC 40 pin flat-flex 0.5mm space

68 Mohr CT100 / CT100HF Operator's Manual

Appendix B: Subassembly Drawings and Parts List

Subassembly Item Part No Qty Description

30 W3W3C1 1 Front panel to 4 button PCB cable 31 W3W3C2 1 Front panel to 5 button PCB cable 32 W3W3C3 1 Front panel to 6 button PCB cable 33 W5W2W7W3C1 1 Digital power assembly cable

Analog-Digicomp CT208

Back Panel CT209

1 A1 1 Analog assembly 2 A2 1 Digicomp assembly 3 CT104 1 Subassembly, analog mounting bracket (aluminum) 4 CT117 1 Shielding enclosure (aluminum) 5 CT306 3 Standoff, round, thru-hole, #6X1/4L 6 CT335 1 Standoff, round, thru-hole, AL, #6X1/4L 7 CT320 5 Standoff, round, thru-hole, #6X3/8L 8 CT321 5 Screw, pan head, cross top, #6-32X5/8L 9 CT326 5 #6 Nylon flat washer 0.062 THK 10 CT327 3 #6 Nylon flat washer 0.032 THK 11 CT343 3 Screw, pan head, cross top, 6-32X9/16L 12 CT311 1 Screw, pan head, cross top, 6-32X1/2L 13 CT333 8 Washer, internal tooth #6 14 CT337 1 Wave disc spring 0.194 ID X .242 OD 15 W1W9C1 1 Coaxial assembly cable 16 W2W1C1 1 Digicomp-analog board FFC cable 17 W2W3C1 1 Serial port cable assembly 18 W2W3C2 1 USB host cable 19 W2W4C2 1 UMCC Plug-plug cable assembly

1 A4A2 1 Fan assembly, 60 x 60 x 25mm 2 A6 1 Back panel assembly 3 CT100-AC-B2700 1 Battery set NiMH with thermistors (2700 mA·h) 4 CT119 1 Frame (aluminum) 5 CT120 1 IO bezel (aluminum) 6 CT121 2 Battery clip (aluminum) 7 CT134 1 Ferrite support bracket 8 CT207 1 Subassembly, Ps-battery charger 9 CT312 4 Screw, fan 10 CT313 10 Screw, pan head, cross top, 6-32x1/4l SS 11 CT338 2 Wave disc spring 0.194 ID X .242 OD 12 CT331 2 Nut, machine 6-32 13 CT333 6 Washer, internal tooth #6 14 M2 1 Ferrite EMI filter 15 W1W5C1 1 Analog power assembly cable 16 W1W5C2 1 Digital power cable to digital side of analog board A1 17 W2W6C1 1 Ethernet assembly cable 18 W2W4C1 1 Serial controller cable 19 W2W6C3 1 USB client cable 20 W2W6C2 1 Ethernet LED cable

Power CT207

1 CT106 1 PS mounting bracket 2 CT306 6 Standoff, round, thru-hole, #6X1/4L 3 CT343 4 Screw, pan head, cross top, 6-32X9/16L 4 CT327 6 #6 Nylon Flat Washer 0.032 THK 5 A4/A5 1 Power Charger assembly 6 CT307 2 Screw, pan head, cross top, 6-32x3/4L

7 CT333 6 Washer, internal tooth #6

Mohr CT100 / CT100HF Operator's Manual 69

Appendix C: Operator

General information

The CT100 and CT100HF Operator Performance Check is a series of procedures used to verify the calibration of a CT100 or CT100HF unit. The following series of checks should be performed after a unit has been newly calibrated to verify compliance to published specifications, but may also be performed to determine if it requires recalibration.

The following series of steps are designed to allow a CT100 operator to completely verify the properties of an individual CT100 unit to each published specification.

NOTE: If a CT100 fails any Operator Performance Check, it should be serviced.

Required equipment

Performance Check

Item MOHR part number

50 Ω precision terminator CT100-AC-ER50 (for CT100)

CT100-AC-ER50S (for CT100HF) Capacitive calibrator CT100-AC-C001 Connector, SMA male to BNC female CT100-AC-ISMBF (for CT100HF) Shorting cap CT100-AC-IBS (for CT100)

CT100-AC-ISS (for CT100HF) 36-inch calibration cable CT100-AC-W536 (for CT100)

CT100-AC-W536S (for CT100HF) Male-male BNC connector CT100-AC-IBMM (for CT100) Additionally, a device capable of taking accurate pulse measurements with documented

calibration will be required.

Getting ready

Disconnect any cables from the front BNC connector. Connect the instrument to a suitable power source, either a fully charged battery (internal or external) or the external 24V power supply connected to a standard 3-prong AC source.

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Appendix C: Operator Performance Check

Reflected Rise Time Check (10-90%)

To measure reflected rise time of an individual CT100 it is important that nanoseconds and millirho are visible on the unit screen. The two units may be enabled within the Display submenu.

To determine the CT100 rise time:

1) Apply the shorting cap to the CT100 front panel cable connector.

2) Ensure that the RRC method is set to the 1502C method.

3) Adjust the on-screen trace so that the internal cable is shown completely. Figure 24 displays the internal cable on a CT100HF unit.

Figure 24: Trace preparation for rise time measurement. The internal cable trace is fully displayed on-screen, and the rising edge is centered.

4) Position the trace so that the leading edge of the internal cable (the left side of the trace) is centered on the screen.

5) Adjust the horizontal scale so that the trace is positioned diagonally across the screen, and adjust the vertical scale so that the left side of the trace runs along the base of the screen and the right side of the trace runs along the top of the screen. The difference between the two sides is considered 100% of the rise time and should be close to 1000mρ.

6) To find the 10-90% rise time, position one cursor at -900mρ and the second cursor at -100mρ. Figure 25 shows a trace correctly positioned for rise time measurement on a CT100HF screen, with the cursors placed at the 10% and 90% points.

72 Mohr CT100 / CT100HF Operator's Manual

Appendix C: Operator Performance Check

The difference in time between the two cursors is the 10-90% reflected rise time.

Figure 25: Cursor placement for determination of 10-90% rise time. The active cursor is at -100.7mρ while the inactive cursor is at -900.3mρ. The difference in time between cursors is the 10-90% rise time, in this case 0.11451 nanoseconds.

Reflected Rise Time Check (20-80%)

This procedure is identical to the Reflected Rise Time Check (10-90%) except that the two cursors should be positioned at -800mρ and -200mρ.

The difference in time between the two cursors is the 20-80% reflected rise time.

Jitter, Noise, and Sampling Efficiency Check

1) Connect a 50 Ω terminator to the CT100 front panel cable connector.

2) From the Main menu, select the Diagnostics menu item to enter the Diagnostics submenu.

3) Select Jitter. After a moment, a results window appears with a list of measurements.

The value for Jitter used in the specification for a CT100 is Jitter P2P, the second value in the second to last line of the results.

The value for Noise is the second number on the first line of the result, Noise P2P.

Output Impedance Check

1) Disconnect any cables from the CT100 front panel cable connector.

2) Position a cursor before the falling edge of the trace.

3) Position the second cursor well beyond the falling edge.

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Appendix C: Operator Performance Check

4) Attach a precision 50 Ω terminator to the CT100.

5) The difference in Ohms between the two cursors is a measure of the deviation of output impedance from 50 Ohms.

Pulse Amplitude Check

Pulse amplitude measurement should be taken with a device that can accurately measure frequency, pulse width, period, and amplitude.

Connect one end of the 36-inch calibration cable to a capable pulse measurement device and the other end of the 36-inch calibration cable to the CT100 front panel cable connector. A waveform should appear on the device display. Switch the CT100 into the short pulse setting from the Main menu. Measure the pulse amplitude coming off the front panel cable connector. The pulse amplitude into 50 Ωs should be between 290mv and 300mv.

Repeat pulse amplitude comparison for medium and long pulse settings.

Pulse Width Check

Pulse width measurement should be taken with a device that can accurately measure frequency, pulse width, period, and amplitude.

Connect one end of the 36-inch calibration cable to a capable pulse measurement device and the other end of the 36-inch calibration cable to the CT100 front panel cable connector. A waveform should appear on the device display. Switch the CT100 into the short pulse setting from the Main menu. Measure the pulse width coming off the front panel cable connector. The pulse width should be between 1 and 100 µsec.

Repeat pulse width comparison for medium and long pulse settings.

Pulse Repetition Rate Check

Pulse repetition rate measurement should be taken with a device that can accurately measure frequency, pulse width, period, and amplitude.

Connect one end of the 36-inch calibration cable to a capable pulse measurement device and the other end of the 36-inch calibration cable to the CT100 front panel cable connector. A waveform should appear on the device display. Switch the CT100 into the short pulse setting from the Main menu. Measure the pulse repetition rate coming off the front panel cable connector. The pulse repetition rate should be between 4 and 125 µsec.

Repeat pulse repetition rate comparison for medium and long pulse settings.

74 Mohr CT100 / CT100HF Operator's Manual

Appendix C: Operator Performance Check

Sequential Sampling Rate Check

The sequential sampling rate is the reciprocal of the pulse repetition time.

Vertical Scale Check

Twist the VERTICAL SCALE knob clockwise. Vertical scale should drop to 0.5mρ and the trace should expand accordingly.

Vertical Accuracy Check

1) Attach a 50 Ω precision terminator to the CT100.

2) Position a cursor on the trace so that it is well after the connection between the CT100 and the

terminator.

3) The absolute value of the vertical measurement in mρ divided by 2000mρ full scale is the

percent error for vertical measurement.

Vertical Position Check

1) Increase vertical scale to 500mρ/div by turning the VERTICAL SCALE knob to the left.

2) Use the VERTICAL POSITION knob to move the live trace completely above the horizontal

midline of the screen.

3) Use the VERTICAL POSITION knob to move the live trace completely below the horizontal

midline of the screen.

A CT100 must succeed at both operations to pass the Vertical Position Check.

Input Susceptibility Check

Input susceptibility is a design value determined by the hybrid manufacturer and cannot be measured by the user.

Distance Cursor Resolution Check

Distance cursor resolution is a value determined by a software constant. It can be measured by counting distinct locations that a cursor may occupy between two division lines, including one of the division lines.

Cursor Readout Range Check

In the Measurement menu, set the cable length to “extra long.”

Mohr CT100 / CT100HF Operator's Manual 75

Appendix C: Operator Performance Check

Turn the HORIZONTAL SCALE knob to the left until horizontal scale is maximized.

Using the M-FUNC button and M-FUNCTION knob, set Vp to 1.

With the HORIZONTAL SCALE knob, position a cursor at the most far right position possible.

The absolute distance measurement for the cursor is the upper limit for cursor readout range. This number should be larger than 10000 meters or 33000 feet.

Position a cursor at the most far left position.

The absolute distance measurement for the cursor is the lower limit for cursor readout range. This number should be less than -1 foot (-0.3 meters).

Cursor Readout Resolution Check

Use the HORIZONTAL SCALE knob to set the horizontal scale to 0.00330 feet/div or 0.001 meters/div.

Position a cursor on the screen and note the absolute distance measurement for the cursor.

Move the cursor the smallest possible step using the HORIZONTAL POSITION knob. The difference between the new distance measurement and the previous is the minimum cursor readout resolution.

Distance Measurement Accuracy Check

Accuracy is determined by taking a cable of known length and velocity and comparing the known values against measured values. Accuracy is reported as a percentage. When determining accuracy, ensure that Horizontal Calibration has been performed accurately.

Accuracy should be checked for short, medium, and long pulse settings.

Ohm Readout Range Check

Connect the 36-inch calibration cable to the CT100.

Position a cursor on the trace well beyond the end of the cable. The vertical impedance measurement should read >=1k ohm.

Position a cursor on the trace well before the leading edge of the pulse. The vertical impedance measurement should read <= 1 ohm.

Resolution Check

Position a cursor at a point of the trace where the vertical impedance measurement is greater than 1 ohm and less than 1000 Ohms. The CT100 should display 3 digits for this measurement.

76 Mohr CT100 / CT100HF Operator's Manual

Appendix C: Operator Performance Check

Vertical Accuracy Check

Vertical accuracy is checked by comparing CT100 resistance (impedance) measurements against a known value. The supplied 50 Ω terminator is required.

To view vertical accuracy, the impedance at cursor must be displayed. Enable impedance at cursor readings from within the Display submenu.

To determine vertical accuracy, connect a 50 Ω terminator onto the front panel cable connector. Move a cursor out to a length greater than 1m. Impedance may change a small amount from point to point. An average impedance amongst a number of points along the trace determines vertical accuracy.

Impedance at cursor should be between 45 and 55 Ohms.

Vertical accuracy should be checked for short, medium, and long maximum cable lengths.

Horizontal Scale Check

From the Main menu, choose the cable length so that it is set to long maximum cable length.

Using the M-FUNC button and M-FUNCTION knob, set Vp to 1.00.

Turn the HORIZONTAL SCALE knob to the left. Horizontal scale should increase beyond 61 meters/div or 200 feet/div.

Turn the HORIZONTAL SCALE knob to the right. Horizontal scale should decrease below 0.01 meters/div or 0.03 feet/div.

Horizontal Range Check

See the cursor readout range instructions above. Horizontal range and cursor readout range are always equal.

Horizontal Position Check

This test is passed implicitly when the Cursor Readout Range and Horizontal Range checks are passed.

Pulse Frequency Check

Pulse frequency measurement should be taken with a device that can accurately measure frequency, pulse width, period, and amplitude.

Connect one end of the 36-inch calibration cable to a capable pulse measurement device and the other end of the 36-inch calibration cable to the CT100 front panel cable connector. A waveform

Mohr CT100 / CT100HF Operator's Manual 77

Appendix C: Operator Performance Check

should appear on the device display. Switch the CT100 into the short pulse setting from the Main menu. Measure the pulse frequency coming off the front panel cable connector. Repeat pulse frequency measurements for short, medium, and long pulse settings. The pulse frequency should be 250 kHz for short, 50 kHz for medium, and 12.5 kHz for long.

78 Mohr CT100 / CT100HF Operator's Manual

Appendix D:

General information

The purpose of this procedure is to calibrate the CT100 to published specifications. Following this procedure will ensure that a CT100 or CT100HF unit will provide accurate measurements within published specifications. This procedure should only be performed if a CT100 is found to need recalibration, or is operating outside of published specifications after following the CT100 and CT100HF Operator Performance Check.

This procedure is not intended to familiarize a user with the instrument. Only experienced users should perform the CT100 and CT100HF Calibration Procedure. Those inexperienced with CT100 operation should read the section titled Operating Instructions.

Calibration procedures must be performed at stable internal and external temperatures. Ensure that the testing environment will have no temperature variation and that the CT100 internal temperature does not fluctuate.

Calibration interval

The CT100 should be calibrated annually as described in this appendix.

Calibration Procedures

Required equipment

Item MOHR part number

50 Ω precision terminator CT100-AC-ER50 (for CT100)

CT100-AC-ER50S (for CT100HF) Capacitive calibrator CT100-AC-C001 Connector, SMA male to BNC female CT100-AC-ISMBF (for CT100HF) Shorting cap CT100-AC-IBS (for CT100)

CT100-AC-ISS (for CT100HF) 36-inch calibration cable CT100-AC-W536 (for CT100)

CT100-AC-W536S (for CT100HF) Male-male BNC connector CT100-AC-IBMM (for CT100)

Optional: At the beginning of calibration, verify pulse properties using an external device capable of taking accurate pulse measurements.

Getting ready

CT100 calibration requires specific device settings before continuing.

1) Disconnect any cables from the front panel cable connector.

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Appendix D: Calibration Procedures

2) Ensure that smoothing is set to 1 by pressing the M-FUNC button (Button 18) until the device displays the smoothing value. Rotate the M-FUNCTION knob counter-clockwise until the smoothing value is set to 1.

3) Set Vp to a value greater than 0.700 by pressing the M-FUNC button (Button 18) until the device displays the Coarse Vp value. Rotate the M-FUNCTION knob until the current Vp is greater than 0.700. Ideally the Vp used should be that of the supplied 36-inch calibration cable. Refer to the label attached to the 36-inch cable for a precise Vp.

4) Set the CT100 to use meters as the length unit. From the main screen press the blue MENU button. Select the Measurement submenu (Button 2). The menu item above Button 4 displays the current units. Press Button 4 until the menu displays “Units meters.”

5) Also on the Measurement menu, set Oversample to “off.”

The following checks and steps must be performed in the order described. The first procedure may be skipped if pulse verification is unnecessary.

Pulse measurement checks (optional)

Pulse measurements should be taken with a device that can accurately measure frequency, pulse width, period, and amplitude.

Connect the CT100 to a capable device using the 36-inch calibration cable. Switch the CT100 into the short pulse setting from the Main menu. Measure each pulse value and compare it against the values given in the supplied CT100 Calibration Certificate. If a certificate is unavailable, the published specifications listed in Appendix A may be used as a basis for comparison. If values fall outside of specifications, discontinue calibration and refer to the Troubleshooting section of the Technical Service manual. Repeat value comparison for medium and long maximum cable lengths.

Turn off temperature adjustment

Temperature adjustment must be disabled to complete the manual calibrations. To disable automatic temperature adjustment:

1) Press the blue MENU button repeatedly until the Main menu appears.

2) Enter the Diagnostics submenu.

3) Enter the Calibration submenu.

4) Read the displayed warning message and select OK to continue.

5) Disable temperature adjustment. Temperature adjustment is disabled when there are no asterisks bracketing the menu item.

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Appendix D: Calibration Procedures

Set manual calibration values

Rough calibration values should be set manually before performing each specific calibration.

To enter manual calibrations from the test screen:

1) Enter the Manual Calibration menu by pressing Button 21 from the Calibration submenu.

Before setting manual calibration values, clear the existing temperature lookup table. To clear the table select Clear Temp Lookup. A warning message will appear. Press Button 4 for OK to continue.

To set the Step Pulse Reference:

1) Press Step Pulse Ref (Button 20) to display the Driver Comp Value on the CT100 screen.

2) Twist the M-FUNCTION knob until the displayed Driver Comp Value reads 10000. This will ensure the driver activation signal is timed correctly.

To set the Timebase DAC value:

1) Display the Sampler Comp value by pressing Timebase DAC (button 21).

2) Twist the M-FUNCTION knob until the displayed Sampler Comp value reads 35000. This will ensure that the timebase DAC sampler voltage is set correctly during calibration.

To set the Hybrid Reference Value:

1) Display the Hybrid Comp value on the CT100 screen by pressing Hybrid Reference (button

22).

2) Twist the M-FUNCTION knob until the displayed Hybrid Comp value reads 45000. This will ensure the Hybrid reference voltage is accurately set during calibration.

Choose the CABLE LEN menu option to set the maximum cable length to a new setting.

Set the Step Pulse Reference to 10000, Timebase DAC value to 35000, and Hybrid Reference Value to 45000.

Choose the CABLE LEN menu option again to set the maximum cable length to the third setting.

Set the Step Pulse Reference to 10000, Timebase DAC value to 35000, and Hybrid Reference Value to 45000.

Capacitive load calibration

1) From the Calibration submenu select the Capacitive Load item (Button 3).

Capacitive load calibration will commence.

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Appendix D: Calibration Procedures

Driver start calibration

1) Start automatic driver calibration by selecting Driver Start from the Calibration menu. Completion of the step may take some time.

Resistive load calibration

1) Remove any attachments from the CT100 front cable connector.

2) Start resistive load calibration by selecting the Resistive Load menu item (Button 4) from the Calibration submenu.

Resistive load calibration will commence. In the resistive load calibration routine the CT100 may display a message instructing the operator to attach a shorting cap or an open to the front of the cable connector. The precise devices required will depend on what sort of cable connector your CT100 has.

Vertical calibration

Vertical calibration should be performed immediately after resistive load calibration has completed. An open attachment is required if the connector on the CT100 is a BNC.

1) If the CT100 has a BNC connector, attach the open.

2) Start vertical calibration by selecting Vertical Calibration (Button 23) from the Calibration submenu.

Vertical calibration will continue and complete.

Manually verify calibration values

After the automated calibrations have completed, it is a good idea to verify the adjusted values and modify them if necessary.

Manually verify capacitive calibration

1) Attach the capacitive calibrator to the front panel cable connector.

2) Rotate the HORIZONTAL POSITION knob until one cursor is at the farthest left point on the

screen. Keep moving the cursor left until the cursor sits at the earliest possible position on the trace.

3) Press the CURSOR button to switch to the second cursor.

4) Move the second cursor across the screen until the change in time between the two

cursors reads close to 50ns. At 50ns from the start of the trace, there is a clock pulse, or

82 Mohr CT100 / CT100HF Operator's Manual

Appendix D: Calibration Procedures

“rollover.” When the capacitive calibration is correct, the timing of the trace is synchronized across the pulse so that the trace before 50ns lines up with the trace after 50ns.

5) Magnify the 50 nanosecond rollover by adjusting vertical and horizontal scale while keeping the live trace on-screen using the VERTICAL and HORIZONTAL SCALE and POSITION knobs. Scale values of 0.1 ft/div (0.03m/div) and 5 mρ/div are acceptable, but a break at a larger scale may be visible.

Figure 26: Example of an incomplete capacitive calibration. The circled area is the 50ns point. The separation between traces is indicative of a CT100 that needs Sampler Comp adjustment.

At this point, the CT100 should display the live trace diagonally across the screen.

If calibration needs additional manual adjustment the live trace will appear to show a break at the 50ns point. Figure 26 displays the appropriate scale. The 50ns rollover is surrounded by a red circle. However, in Figure 26, the capacitive calibration needs to be adjusted. Figure 27 displays a trace that does not need manual capacitive calibration.

If adjustment is necessary, adjust the Sampler Comp value until the live trace shows no breaks as per Figure 27. If the trace appears linear across the 50ns rollover, steps 6 through 9 may be skipped.

6) Enter the Calibration submenu

7) Enter the Manual Calibration submenu

8) Select Timebase DAC by pressing Button 21.

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Appendix D: Calibration Procedures

9) Rotate the M-FUNCTION knob until the live trace appears linear as in Figure 27.

Figure 27: Example of a correctly set capacitive calibration. The circled area is the 50 rollover. Compare against Figure 26 where manual adjustment is necessary.

10)Repeat steps 1 through 9 for short, medium, and long maximum cable lengths.

Manually verify resistive load calibration

The following text discusses the manual resistive load calibration procedure, which you can use at any time to check and/or manually adjust the vertical calibration of the instrument for maximum precision of vertical measurements. From the Main menu, select Calibration, press OK when the warning appears, and then select Manual Calibration.

1) Remove all cables from the front panel cable connector.

2) Adjust the CT100 scale to 0.5 ft/div (0.15 m/div) and 500 mρ/div.

3) Place the cursor as shown in Figure 28 on the rising edge of the internal cable segment.

4) Center the cursor in the middle of the screen using the position knobs.

5) Expand the scale to 0.070 ft/div and 40 mρ/div.

6) Push the Hybrid Comp button to start the manual resistive load calibration. The automatic calibration option is discussed elsewhere in this manual. At this point the words “Hybrid Comp” appear at the top of the screen with a 5 digit number as shown in Figure 28. This trace is typical of a CT100 with the self-grounding BNC test port and/or with a shorting terminator applied. The CT100HF does not have the shorting BNC and will show an open condition at the end of the trace if a shorting terminator is not applied.

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Appendix D: Calibration Procedures

Figure 28: Typical trace from a CT100 with a shorting terminator applied to the test port. The active cursor is set at the reflected rise. The right hand side of the trace shows the effect of the shorting terminator.

7) The next step is to adjust Hybrid Comp to minimize the vertical shift that occurs when

changing between open and short conditions. The value of Hybrid Comp can be adjusted by turning the M-FUNCTION knob on the front panel. For CT100 units with the selfgrounding BNC test port, a male–male BNC adapter is used to provide an open condition. For CT100HF units with an SMA test port, leave the test port empty.

Figure 29 shows an open condition at the test port. The apparent reflection coefficient of the trace has changed from 31 mρ to -53.6 mρ, indicating that an adjustment of Hybrid Comp is required.

Figure 29: Hybrid Comp adjustment with open BNC and cursor at the reflected rise. Note for most applications the horizontal gain should be at 0.004 ft/div and the vertical scale should be set at 2 mρ/div. The male–male BNC adapter can be used to provide an “open” condition.

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Appendix D: Calibration Procedures

Figure 30 shows the open trace after adjustment of Hybrid Comp with the vertical and horizontal gain set to the recommended ranges.

Figure 30: Hybrid Comp adjustment with open terminator and cursor at the reflected rise. The horizontal scale is set at 0.004 ft/div and the vertical scale is set at 2 mρ/div. The male–male BNC adapter can be used to provide an “open” condition.

Figures 31 and 32 show the deviation in vertical position of the trace after adjustment of Hybrid Comp and application of a shorting terminator. For better accuracy, high horizontal and vertical gain should be used, as in Figures 30 and 32.

Figure 31: Hybrid Comp adjustment with the shorting terminator and the cursor at the reflected rise. Hybrid Comp has been adjusted so that the reflection coefficient of the trace is unchanged between short and open. The horizontal scale should be 0.004 ft/div and the vertical scale should be set to 2 mρ/div to obtain maximum accuracy.

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Appendix D: Calibration Procedures

Notice that the reflection coefficient indicated on the screen changes from 30.1 to 29.0 between open and short (Figures 30 and 32) for a difference of 1.1mρ, an acceptable variation.

Steps 1 through 7 must be carried out separately for short, medium, and long cable length settings.

Figure 32: Hybrid Comp adjustment with the shorting terminator and the cursor at the rising edge. The Hybrid Comp value has been changed so that the reflection coefficient of the trace is unchanged whether or not the port condition is short or open.

Enable temperature adjustment

Before finalizing calibration, automatic temperature adjustment should be re-enabled. To reenable temperature adjustment from the Main menu:

1) Enter the Calibration submenu by selecting the Calibration menu option.

2) Select the Temperature Adjustment menu item to enable temperature adjustment. When

temperature adjustment is enabled, the menu item will be bracketed by asterisks (*).

Horizontal calibration

Horizontal calibration sets the start position for distance measurements. For precise measurements it is extremely important to perform horizontal calibration as accurately as possible.

To horizontally calibrate the CT100:

1) Connect the shorting cap to the front panel cable connector.

2) Set smoothing to 64 frames.

3) Position one cursor immediately before the falling edge of the live internal cable trace.

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Appendix D: Calibration Procedures

4) Center the cursor in the middle of the screen using the position knobs.

5) Expand the scale to 0.0100 ft/div and 1.0 mρ/div.

6) Locate the small break in slope on the falling edge shortly after the final peak on the live internal cable trace.

It may be necessary to adjust the scale further to find the obvious break point signifying the cable end. Refer to Figure 33 for an example.

7) Position one cursor at the end of the break point.

8) Enter the Calibration submenu.

9) Press Horizontal (Button 5) to set horizontal calibration.

10) Press Button 4 for OK to continue.

Figure 33: Identification of cable start position. The circled portion of the trace is the point signifying the front panel cable connector. The active cursor should be moved to the flat section of the trace pointed to by the arrow.

Horizontal calibration must be set for each pulse setting. Change to the next pulse setting and repeat steps 1 through 9. Repeat again for the final pulse setting.

After horizontal calibration, measure a known length of cable to verify accurate start point positioning.

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Appendix D: Calibration Procedures

Clear temperature lookup table

After calibration is completed, it is necessary to clear the temperature lookup table used to expedite temperature calibration while the CT100 is in use. Clearing this table will force the temperature lookup table to be rebuilt using the newly calibrated values.

To clear the temperature lookup table:

1) From the main screen, push the blue MENU button.

2) Enter the Calibration submenu (Button 4).

3) Select OK to continue (Button 4).

4) Select Manual Calibration (Button 21).

5) Select Clear Temp Lookup by pressing Button 23. A warning message will be displayed

asking to verify the clearing of temperature adjustment.

6) Select OK to complete clearing the temperature lookup table.

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Appendix E: Operator

General information

Use this troubleshooting guide when there is a problem with a CT100 or to assist with problem identification. This will help you to determine if the instrument should be repaired or is acceptable to continue using.

Any time one of the internal thermal fuses actuates with an audible click, indicating thermal overload, turn off the rear panel battery-disconnect switch immediately and have the instrument serviced as soon as possible.

CAUTION: DO NOT continue using the CT100 if it exhibits signs of thermal overload, such as emitting heat or smoke, or if it smells of burning plastic.

Power on test

Verify that the back switch is in the ON position. Press the red front button to turn the instrument on. If the instrument does not show anything on the screen within 20 seconds, turn the back switch to the OFF position, unplug all USB and Ethernet devices, and attempt to turn it on again.

Troubleshooting

Functional block diagram

Use the following functional block diagram and troubleshooting flowcharts for various parts of the CT100 to determine if your CT100 requires service.

Mohr CT100 / CT100HF Operator's Manual 91

and

troubleshooting flowchartss

troubleshooting flowchart

Appendix E: Operator Troubleshooting

92 Mohr CT100 / CT100HF Operator's Manual

DC Power Supply

Diagnostics

Plug 24 volt DC

power supply into

a wall socket

Does the light on the

power supply come on?

Make sure the

power supply is

firmly plugged in.

Does the light on the

power supply come on?

Test outlet with

working device or

outlet tester.

Does the

outlet work?

Change to a

working outlet

Device power supply

is likely defective .

Replace it with a functional supply

yes

Power Board and

Fan Diagnostics

Start Mohr CT100

Diagnostics

DC Power Supply

Fan and Power

Board

Screen and

Computer

Front Panel

Main Board

Analog

Finished

Diagnostics

Main Diagnostic

Sequence

DC Power Supply

RTC

Operations

File

Appendix E: Operator Troubleshooting

Mohr CT100 / CT100HF Operator's Manual 93

Appendix E: Operator Troubleshooting

Plug DC Power

Supply into the

back of the CT100

Does the fan

in the back of the

CT100 turn on?

Replace DC

PowerSupply

Does the fan

in the back of the

CT100 turn on?

Send in for

servicing

Turn on power

switch in the back

of the CT100

yes

Power Board and

Fan Diagnostics

Screen and Computers

Diagnostics

Power Board and Fan

94 Mohr CT100 / CT100HF Operator's Manual

Mohr CT100, CT100HF Operator's Manual

Specifications and Main Features

Frequently Asked Questions

User Manual