Agilent Technologies 1142A, 1141A User Manual

User and Service Guide

Publication number 01141-97002 July 2004

For Safety and Regulatory information, see the pages at the end of this book.

Agilent Technologies 1141A Differential Probe and 1142A Probe Control and Power Module

This manual contains information for use and service of the differential probe system, the 1141A Differential Probe and 1142A Probe Control and Power Module. In this document, the two models will be treated as a system.

Each of the two instrument models that make up the differential probe system has a serial number sticker. The sticker for the 1141A Differential Probe is inside the probe, in the bottom cover. (See chapter 3 for disassembly procedure.)

The 1141A/1142A probe system allows measurement of small differential signals in the presence of much larger common-mode signals. It has the following major features:

• 200 MHz bandwidth

• Variable offset

• dc reject

• ac coupling

• Remote operating capability

The variable offset capability can be used to measure small ac signals in the presence of much larger dc levels. Remote operation of key features allows the use of the probe system in automatic test situations.

The probe can be used with an oscilloscope, spectrum analyzer, or any instrument where differential probing is required and a compatible 50 Ω input is available.

1 Operating the Probe

Accessories Supplied 6 Accessories Available 8 To inspect the probe 9 Using the probe with other instruments 9 Recommended Test Equipment 9

2 Calibration Tests and Adjustment

Equipment Required 26 The Test Board 26

Calibration Tests 27

dc Gain Accuracy 28 Bandwidth 34 CMRR Test 36 Calibration Test Record 39

Adjustments 40

Probe Adjustment 40 Adjustment Procedure 42 Attenuator Adapter Adjustment 49

3Service

Introduction 54

Performance Specifications and Characteristics 55

General Characteristics 58

Contents

Theory of Operation 59

Differential Probe 60 Control and Power Module 60 Attenuator Adapters 61 Test Board 62

Service Policy 63

Troubleshooting 64

Probe Troubleshooting 64 Probe Control and Power Module Troubleshooting 64

Removing and Replacing Assemblies 66

Differential Probe 66 Probe Adapters 68 Probe Control and Power Module 70

Replaceable Parts 71

Parts List 71 Ordering Information 71 Direct Mail Order System 71 Manufacturers’ Codes 72 Exploded View 73

Operating the Probe

Accessories Supplied

Introduction

This chapter shows you how to connect and operate the 1141A Differential Probe and 1142A Probe Control and Power Module as a differential probe system.

Accessories Supplied

The following items are supplied as part of the 1141A/1142A probe system. Item numbers refer to the numbers in Figure 1-1 on page -7 and Figure 1-2 on page -8. Those without item numbers are supplied but not shown in figures. See the Replaceable Parts List for parts not listed below.

Item Description Qty Part Number

1 Differential Probe 1

2 10x Attenuator Adapter 1 5063-2144

3 100x Attenuator 1 5063-2145

4 ac Coupling Adapter 1 5063-2146

5 Two-inch Extension Leads (package 5) 1 5959-9334

6 Mini Grabbers 2 1400-1422

7 Five-inch Ground Lead 1 5061-6162

8 Shielded Signal Lead 1 01141-68702

9 Test Board 1 01141-66504

10 Flat-blade Alignment Tool 1 8710-1961

11 Circuit Connection Posts (strip of 20) 1 1251-5943

Probe Control and Power Module 1 1142A

Power Cord 1 see parts list

Carrying case

User and Service Manual 1

Figure 1-1

Operating the Probe

Accessories Supplied

1141A Differential Probe and Accessories

Figure 1-2

Figure 1-3

Operating the Probe

Accessories Available

1141A Miscellaneous Accessories

1142A Probe Control and Power Module

Accessories Available

The following accessories can be ordered.

• 5959-9335 Long Extension Lead (5.5 inch/14 cm), package of 5

• 5090-4833 Mini grabber for SMT, package of 20

Operating the Probe

To inspect the probe

Inspect the shipping container for damage. If the shipping container or cushioning material is damaged, it should be kept until the contents of the shipment have been checked for completeness and the instrument had been checked mechanically and electrically. Accessories supplied with the instrument are listed in see “Accessories Supplied” on page 6 of this manual.

If the contents are incomplete, if there is mechanical damage or defect, or if the instrument does not pass calibration tests, notify the nearest Agilent Technologies office. If the shipping container is damaged, or the cushioning materials show sign of stress, notify the carrier as well as the nearest Agilent Technologies office. Keep the shipping materials for the carrier’s inspection. The office will arrange for repair or replacement at Agilent Technologies’ option without waiting for a claim settlement.

Using the probe with other instruments

The 1141A/1142A probe system can be used with other instruments as well as oscilloscopes. You can use it with a spectrum analyzer or frequency counter, or any instrument with an input that can be terminated with 50 Ω.

If you are going to use the probe system with an instrument other than an oscilloscope, you may need to set up the probe with an oscilloscope first. This will allow you to select coupling and reject modes, and set offset, so the output of the probe is compatible with signal requirements of the other instrument.

Recommended Test Equipment

The following table is a list of the test equipment required to test calibration, make adjustments, and troubleshoot this instrument. The table indicates the critical specifications of the test equipment and for which procedure the equipment is necessary. Equipment other than the recommended model may be used if it satisfies the critical specifications listed in the table.

Recommended Test Equipment

Recommended

Equipment Required Critical Specifications

Signal Generator 1 to 200 MHz, 400 m V

Function Generator 2.5 to 500 kHz, 600 m V

Oscilloscope >400 MHz bandwidth, 1 mV/div sensitivity 54830B P,A

dc source ± 100 mV to 7 Vdc E3632A P

rms

p-p

to 16 V

p-p

Agilent Model/Part Use

8648A P

33120A A

Operating the Probe

Recommended Test Equipment

Recommended

Equipment Required Critical Specifications

Test Board No substitute (supplied accessory) 01141-66504 A

Load BNC Feedthrough, 50 Ω Pasternack

Cables (2) BNC, 50 Ω 36-inch 10503A P,A

Cable BNC, 50 Ω 9-inch 10502A A

Cable Type N (m) 24-inch 11500B P

Adapter Type N (m) to BNC (f) 1250-0780 A

Adapter Type N (f) to BNC (m) 1250-0077 P

Adapters (2) BNC (f) to dual banana (m) 1251-2277 P

Agilent Model/Part Use

P Enterprises PE600850 or Huber+Suhner 22543742

Alignment tool Small flat blade (supplied accessory) 8710-1961/

Sprague-Goodman part number GTT-5G

P=Calibration Tests, A=Adjustments

Setting up the probe

The following paragraphs cover system preparation and initial adjustments.

Power Requirements

The 1141A/1142A probe system (specifically the 1142A) requires a power source of either 90 to 132/198 to 264 Vac, 47 to 440 Hz, 25 VA maximum.

CAUTION Before connecting power to this instrument, be sure the line voltage switch on the rear

panel of the instrument is set properly.

Line Voltage Selection

Before applying power, verify the setting of the LINE SELECT switch on the rear panel of the 1142A. The slide switch can be set to either 115 or 230 V.

Operating the Probe

Recommended Test Equipment

WARNING Before connecting this instrument, the protective earth terminal of the instrument must

be connected to the protective conductor of the (Mains) power cord. The Mains plug must be inserted in a socket outlet provided with a protective each contact. The protective action must be negated by the use on an extension cord (power cable) without a protective conductor (grounding). Grounding one conductor of a twoconductor outlet does not provide an instrument ground.

This instrument is provided with a three-wire power cable. When connected to an appropriate ac power outlet, this cable grounds the instrument cabinet. The type of power cable plug shipped with the instrument depends on the country of destination.

The 1142A Power Control and Power Module does not have a power switch. A power switch is not required because of the low mains power requirement.

Figure 1-4

1142A Rear Panel

Procedure

Use the power cord to connect the 1142A to the ac mains.

1 2 Connect the 1141A probe cable power connector to the PROBE connector on

the rear panel of the 1142A power module.

3 Connect the output of the probe to the input of the oscilloscope. 4 Set the input impedance of the oscilloscope to 50 Ω.

If the oscilloscope does not have a selectable 50 Ω input impedance, connect a 50 Ω BNC feedthrough termination between the probe output and the input of the oscilloscope.

5 If making an initial equipment setup, continue with the initial adjustment in

the following section.

Initial Adjustment

For a given combination of 1141A Differential Probe and 1142A Probe Control and Power Module, you may want to adjust the Offset Null and DC Reject Gain. Typically, you need to make these adjustments only once, before the probe is first used. You can make them any time to optimize the system. These adjustments do not affect the specifications of the probe system.

Figure 1-5

Operating the Probe

Recommended Test Equipment

• Offset null zeroes the dc level at the output of the probe. The range of adjustment is about ±4 mV.

• DC Reject Gain adjusts the gain of the dc reject circuit to accurately null the dc component of an input signal. The range of adjustment is about ±0.5%.

1142A Front Panel

Equipment Needed

The following equipment is necessary for initial adjustment.

• 5 V power supply

• DVM that can measure 25 µV

•50 Ω BNC feedthrough terminator

• 01141-66504 test board

Equipment Setup

Use the following procedure to setup the differential probe system for initial adjustment.

CAUTION Do not exceed ±7 V when using the test board for this procedure. If the voltage is too

high, it will cause excessive power dissipation in the 50 Ω termination on the test board.

1 Use the probe setup procedure to set up the probe system. 2 Connect a 50 Ω BNC feedthrough terminator to the output of the probe. 3 Disconnect all accessories from the input of the probe. 4 Connect the DVM to measure the dc output of the probe at the 50 Ω load.

Figure 1-6

Operating the Probe

Recommended Test Equipment

5 Set up the 1142A:

a Set the Local/Remote push button to Local. b Under DC Couple, press Zero offset.

6 Set the power supply output to 5 V. 7 Arrange a connection between the power supply and the test board. The

negative terminal of the supply should connect to the shield of the test board BNC.

If your power supply has standard binding posts, you can connect a banana-to-BNC adapter to the supply and connect a BNC cable between the supply and the test board.

Adjustment

Warm up the 1141A for 30 minutes before making adjustments.

With the 1141A probe inputs unconnected, adjust Offset Null on the 1142A for a minimum reading on the DVM.

The voltage swing of the adjustment is approximately ±4 mV.

On the 1142A, under DC Reject, press 5.0 Hz.

2 3 Read and record the reading on the DVM, _________ mV. 4 Connect the probe to the test board in the position shown below

(signal to + input).

Signal to + input

5 After the DVM reading stabilizes, adjust DC Reject Gain to the reading recorded

in step 3.

With a 5 V supply, the voltage swing is approximately ±12.5 mV. With a lower supply, the voltage swings proportionally less.

Using the Accessories

The 1141A Differential Probe and accessories are designed to provide a variety of ways to connect to circuitry and make measurements. In the descriptions, any method used to connect to the probe signal inputs also applied to the adapters. The figure below shows, in a general way, the use of accessories.

Figure 1-7

Operating the Probe

Recommended Test Equipment

Basic Accessory Connections

Probe Tips

Probe tips fit into the receptacles in the probe and are held in place with probe tip caps. If necessary, you can solder the probe tips into a circuit or wires can be soldered to the

tips. If you solder to the probe tips, be careful not to melt the plastic probe tip caps.

Note Because of the close tolerances between the probe tip caps and probe tips, it will be

difficult to separate the probe tips and caps once the probe tips have been soldered.

Ground Leads

The circular end of the ground lead fits over the screw on the top side of the probe.

Extension Leads

The extension leads provide a flexible connection between circuitry and the probe.

• To provide a male connection to other circuitry, connect the extension lead over the probe tips.

• To provide a female connection, remove the probe tip caps and probe tips and connect the extension leads to the probe.

Operating the Probe

Recommended Test Equipment

Note Use extension leads and similar connection accessories carefully. Extension leads

compromise the high-frequency specifications of the probe. CMRR is particularly sensitive to unbalanced input parameters.

To prevent pickup of stray fields when you use extension lead, either the ones supplied with the 1141A or others, dress them carefully as follows:

• Connect the leads at right angles to the circuitry under test.

• Keep the leads as parallel as possible before they connect to the probe.

Mini-Grabbers

Mini-grabbers can be attached to the probe or adapter through the extension leads.

Remove the probe tip caps and tips.

2 Attach the extension leads to the probe or adapter. 3 Attach the mini-grabbers to the extension leads.

Circuit Connector Posts

These 0.025-inch square posts can be used to connect either directly to the probe or to the extension leads.

Solder the posts directly into your circuitry or use them to make extension leads that plug into the inputs of the probe or adapters.

Shielded Signal Leads

The shielded signal leads allow connection to points in a circuit that are up to 10 inches apart. The leads are shielded to within approximately 1/2 inch of the end of the lead so they minimize pick-up due to stray fields from adjacent circuitry.

Connect the end with the ground connector to the probe pins and ground of the differential probe or adapter.

2 Connect the free ends of the leads to 0.025-inch square or 0.030-inch round pins

in your circuitry or to the mini-grabbers.

Note Each lead has an input capacitance of approximately 15 pF. This capacitance may limit

the bandwidth of your measurement (depending on the impedance of the circuit). Also, CMRR may be affected because of slight differences between the input capacitance of the two leads. CMRR is also affected by differences in impedance between the two measurements points.

Figure 1-8

Operating the Probe

Recommended Test Equipment

Adapters

There are three adapters for use with the differential probe. Two adapters are attenuators, a 10x and a100x. The other is an ac adapter for blocking dc from the probe input.

The adapters are installed on the probe after the probe tip caps and probe tips have been removed. The adapter fastens to the probe using a thumb wheel located on the underside of the adapter. the figure below shows a good way to hold the probe while attaching the adapter.

Remove the probe tip caps and probe tips, from the probe.

2 Fit the adapter over the end of the probe and rotate the thumb wheel with your

finger until the adapter fits snugly.

A snug fit is important because the ground is maintained through the thumb wheel screw. A loosely attached adapter compromises the mechanical and electrical integrity of the combination.

Attaching the Adapters

Figure 1-9

Operating the Probe

Recommended Test Equipment

Adapter Combinations

The figure below shows the allowed adapter and probe connections. There are two specific combinations that should not be used.

• Do not attach the ac adapter between an attenuator adapter and the probe. An attenuator adapter must be terminated by the input resistance of the probe. The

ac adapter isolates the probe input resistance.

• Do not cascade two attenuator adapters. The attenuator adapters are designed to be terminated by the 1 MΩ resistance of the

probe. The input resistance of the attenuator adapter is 9 MΩ for the 10x adapter and 10 MΩ for the 100x adapter.

Allowed Adapter Connections

Figure 1-10

Operating the Probe

Recommended Test Equipment

Connector Compatibility

The following are general connector characteristics for the probe, adapters, and accessories.

• The female connectors on the probe, adapters, and other accessories are designed to mate with 0.030-inch round or 0.0250-inch square pins.

• The probe, adapter, and extension lead pins are 0.030-inch round.

• The strip of circuit connection posts provided as an accessory has 0.025-inch square pins.

• The mini-grabber has a 0.25-inch square pin.

• The ground connection at the end of the probe and adapters (where the adapters fasten) accepts an M3 metric screw.

Test Board

The primary use of the test board is to apply test and calibration signals to the input of the probe or adapters. Specific use of the test board is covered wherever it applies.

Grounding

Grounding is very important when probing circuitry. Improper grounding can increase the common mode signal level. This reduces the effectiveness of the differential probe.

The mechanical connections at the input of the probe are ground for probe signals. The screw where the ground lead attaches (see figure 1-7) fastens to this ground. Also, the attenuator and ac adapter fasten to this ground through the screw connection and the ground is carried through each adapter to its front.

Probe Grounds

Coupling Functions

There are three methods for blocking or compensating for the dc component of a signal. Each has specific advantages.

Probe System Coupling Functions

Operating the Probe

Recommended Test Equipment

dc offset dc Reject ac Coupling

Adapter

dc Blocked

Probe alone

Probe with 10x

Probe with 100x

Set-up needed

± 20 V ± 200 V ± 500 V

Adjust offset to put signal on screen

Remote Control? Yes

CMRR

No No Yes

± 20 V ± 200 V ± 500 V

Select DC Reject low-frequency corner

Yes

± 20 V ± 500 V ± 500 V

Attach ac Coupling adapter to differential probe

degradation?

Low-frequency

No Yes Yes

degradation?

Isolated external dc reference and control signals are needed

dc Reject

dc Reject is the best method of eliminating the dc component of a signal when dc is not a factor in the measurement.

The key characteristics are:

• The low-frequency component (from dc to the selected corner frequency) is automatically nulled by the dc reject circuitry.

• Probe CMRR specifications are not compromised as happens when the ac coupling adapter is uses.

• There is a selectable low frequency corner with -3dB points at 0.05 Hz, 0.5 Hz, or 5.0 Hz.

• The voltage reject range is ±20 V with the probe alone, ±200 V with the 10x attenuator, and ±500 V with the 100x attenuator.

Operating the Probe

Recommended Test Equipment

To use dc reject:

Remove the ac adapter if it is installed.

1 2 On the front panel of the 1142A, press Local. 3 Under DC Reject on the front panel, press 5.0 Hz or 0.5 Hz individually, or

5.0 Hz and 0.5 Hz simultaneously to get 0.05 Hz.

Within the frequency and voltage characteristics noted elsewhere in this manual, low frequencies are nulled from the input signal.

Offset

Offset is the best method to use when the low-frequency corners associated with dc reject and the ac adapter interfere with the measurement.

The key characteristics are:

• The user manually null the dc component with the offset adjustment.

• Offset is dc coupled so there is no low frequency roll-off.

• Probe CMRR specifications are not compromised as happens when the ac coupling adapter is used.

• The voltage offset range is ±20 V with the probe alone, ±200 V with the 10x attenuator, and ±500 V with the 100x attenuator. (With the 100x attenuator, the offset range is restricted by the maximum input voltage rating rather than the operating range of the offset).

To use offset:

Remove the ac adapter if it is installed.

2 On the front panel of the 1142A, press Local and Variable offset. 3 Adjust the Coarse and Fine Variable Offset until the signal is displayed on the

screen of the oscilloscope.

ac Adapter

The ac adapter must be used when the dc component of the signal exceeds the operating range of the dc reject or offset methods. The ac adapter block the dc and low frequency component of the input by forming a high pass filter with the input impedance of the probe or adapter.

The key characteristics are:

• The ac adapter safely blocks ±200 Vdc when attached directly to the probe or ±500 Vdc when attached to a 10x or 100x adapter.

• The probe and adapters have different input impedances, so they have different low frequency corners with the ac adapter. When the ac adapter is directly on the probe the -3dB corner is 15 Hz. When the ac adapter is on an attenuator the corner is 1.5 Hz.

• The low-frequency CMRR when using the ac adapter is not as good as when using the probe alone or the probe with a 10x or 100x adapter.

CAUTION If you measure a node having a high dc potential, the blocking capacitors in the ac

adapter will charge to that potential. After making such measurements, discharge the capacitors by grounding both inputs of the ac adapter. This will prevent damage by a high voltage discharge into sensitive circuitry when the next measurement is made.

Operating the Probe

Recommended Test Equipment

To use ac coupling:

Attach the ac coupling adapter to the input of the probe or the input of the

attenuator adapter.

2 On the 1142A, press Local and Zero offset.

Remote operation

For automatic test applications, the coupling and offset functions provided by the 1142A Probe Control and Power Module can be remotely controlled through a connector on the rear panel of the module. The connection is through a standard 9-pin female D-subminiature connector. This style is the same as that used on some personal computer monitor cables, which provides an economical way to connect the 1142A to the controller interface on an automatic test system.

The following table gives the connections.

Remote Input Connections

Pin Function Pin Function Connector

1 Function Select 1 (A1R) 6 Function Select 0 (A0R)

2 Digital common 7 N.C.

3N.C. 8N.C.

4 External offset common 9 External offset

5 Shield

NOTE To minimize dc offset errors and potential noise coupling, electrically isolate all

connections between the Remote Input connector and the controlling system.

Operating the Probe

Recommended Test Equipment

Function Select

The easiest way to control the function select lines is contact closures between the lines and Digital common (pin 2) of the remote input connector. (TTL compatible control signals can be used; but to avoid problems with ground loops, they must be electrically isolated.) The following truth table shows the functions provided by the function select lines. For the Remote Inputs, “0” represents a closure and “1” represents an open circuit.

Remote Functions Select Truth Table

Remote Input Function

A1R

(Pin 1)

0 0 0.05 Hz Reject

0 1 0.5 Hz Reject

105 Hz Reject

1 1 DC Couple

Variable Offset

The remote variable offset can be used when the dc couple function is remotely selected. The offset voltage must be referenced to the External offset common (pin 4) of the remote input connector. It must be electrically isolated from the controlling system. The following table shows the offset range and remote offset requirements for probe and adapter combinations.

Remote Offset Input Requirements

Probe alone ± 20 V ± 10 V

Probe with 10x adapter ± 200 V ± 10 V

Probe with 100x adapter ± 500 V ± 2.5 V

A0R

(Pin 6)

Offset Range Remote

Requirements

Cleaning Requirements

If the instrument requires cleaning: (1) Remove power from the instrument. (2) Clean the external surfaces of the instrument with a soft cloth dampened with a mixture of mild detergent and water. (3) Make sure that the instrument is completely dry before reconnecting it to a power source.

Operating the Probe

Recommended Test Equipment

Differential Amplifiers and CMRR

The 1141A Differential Probe is a high-impedance differential amplifier. A characteristic of differential amplifiers is the ability to reject signals that are common to the two inputs. The common mode rejection ratio (CMRR) is the measurement of this ability. It is expressed as the ratio between the amplitudes of the common mode and differential signals which product equal outputs. For example, if a common mode signal of 1 V and differential signal of 1 mV both produce outputs of 1 mV, the CMRR is 1000:1.

The ability to reject common mode signals is dependent on the balance designed into the differential amplifier. At higher frequencies it becomes harder to balance circuit parasitics and parameters of devices so CMRR degrades as frequency increases. Also, stray coupling increases with frequency and coupling may vary between the two differential paths.

The CMRR of the 1141A Differential Probe is specified at the input of the probe and cannot be affected expect by adjustments in the probe. However, the way the probe is connected into the circuitry being tested can have a big influence in the overall result of the measurement, especially at high frequencies.

The following things can affect the effective CMRR of a test setup:

• The connection to the circuit under test. The method used to connect the probe is important because it involves the symmetry

of the differential input circuitry. For example, using different lengths of wire to connect the circuit to the two probe inputs unbalances the inductance and capacitance at the inputs. The effective CMRR will be reduced, especially at high frequencies. Additionally, coupling from adjacent circuitry will be less balanced.

• The impedance of the source. This is another instance where the symmetry of the differential circuit is important.

The impedance of the source forms a network with the input impedance of the source forms a network with the input impedance of the connections and the probe. This network determines the frequency response for the measurement. If each side of the differential source has a different impedance, the frequency response of each side will be different and the unbalance is reflected in a reduced CMRR. Of course, lower source impedances have less effect on the frequency response of the measurement.

• The ground connection. A poorly located ground connection allows ground loops to add to the common mode

signal.

• Frequency. Frequency is the most important factor in CMRR only because all of the factors

mentioned above are frequency dependent. The unbalances of capacitance and inductance are more important as frequency increases. Therefore, good highfrequency practice is important when using a high impedance differential probe.

On the other hand, if the differential probe is ac coupled to the circuit under test (the ac adapter is being used) the CMRR will be degraded below a certain frequency; the lower the frequency the worse the CMRR. This is because unbalance in the series capacitances of the ac coupler becomes more significant the lower the frequency.

Operating the Probe

Recommended Test Equipment

Calibration Tests and Adjustment

Equipment Required

Introduction

This chapter is divided into two sections. The first section gives calibration tests and the second adjustment procedures for the 1141A Differential Probe and 1142A Probe Control and Power Module.

Equipment Required

A complete list of equipment required for the calibration tests and adjustments is listed in “Recommended Test Equipment” on page 9. Equipment required for individual procedures is listed at the procedure. Any equipment satisfying the critical specifications listed may be substituted for the recommended model.

The Test Board

The test board is a supplied accessory for use during calibration tests and adjustments to connect signals to the differential probe (with or without adapters). A BNC connector connects the test board to a cable from the signal generator. The board includes a 50 Ω termination (two 100 Ω resistors).

CAUTION The power rating of the 50 Ω termination is 1.0 W. Keep the signal input below 7 Vdc

or rms to avoid degrading the termination.

Once the probe tip caps and probe tips have been removed, the probe can be connected to the test board in one of three ways, as shown in the figure below. At each position of the probe, probe inputs are connected to a different combination of signal and ground. A separate terminal on the test board connects the ground of the probe to the signal ground.

Figure 2-1

Test Board Showing Probe Positions

Calibration Tests and Adjustment

The Test Board

Calibration Tests

These procedures test the probe’s electrical performance using applicable specifications given in “Performance Specifications and Characteristics” on page 55 as performance standards. Specifications applicable to individual tests are noted at the test for reference.

Testing Interval

The calibration testing procedures may be performed for incoming inspection of the instrument and should be performed periodically thereafter to ensure and maintain peak performance. The recommended test interval is yearly or every 2,000 hours of operation. Amount of use, environmental conditions, and the user’s experience concerning need for testing will contribute to verification requirements.

Calibration Test Record

The results of the calibration tests may be tabulated in the Calibration Test Record provided at the end of the calibration tests. The Calibration Test Record listed the calibration tests and provides an area to mark test results. The results recorded in the Calibration Test Record during initial inspection may be used for later comparisons of the tests during periodic maintenance, troubleshooting, and after repairs or adjustments.

Calibration Test Procedures

Procedures may be done individually or in any order.

NOTE Allow the instrument to warm up for at least 30 minutes prior to beginning calibration

tests.

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