TTI 1705 Instruction Manual

THURLBY THANDAR INSTRUMENTS

Model 1705

PROGRAMMABLE TRUE RMS MULTIMETER

INSTRUCTION MANUAL

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 1

Table of Contents

Introduction 2

Specifications 3

Safety 8

EMC 9

Installation 10

General Operation 12

Making Basic Measurements 16

Dual Measurement Mode 19

Advanced Features 21

Data Logging and Printing 25

Calibration 27

Maintenance 28

Remote Operation 29

Remote Commands 34

General Commands 34

Main Display Commands 35

Dual Measurement Mode Commands 37

First Level Modifier Commands 37

Second Level Modifier Commands 38

Data Logging Commands 39

Calibration Commands 40

Default Settings 41

1

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 2

Introduction

This programmable true RMS multimeter has dual measurement capability and a dual display †
which can show either two independent measurements, a measurement together with its range or
a measurement with one of the many calculated functions available.

The key features are:

• Large, high contrast, liquid crystal dual display.

• 0.04% basic accuracy, 12000 counts.

• Manual or autoranging.

• DC and AC Volts, DC and AC current, Resistance, Capacitance, and Frequency measurement;

Continuity and Diode checks.

• True RMS AC and AC+DC measurement.

• Display nulling and Ohms null.

• Touch hold mode - holds onto a stable reading until updated.

• 100 point data logger.

• Measurement post-processing to give:

dB and power measurement with settable reference impedance

percentage deviation from a user-entered reference

linear scaling with offset

limits comparison for go/no go testing

automatic storage of minimum and maximum readings.

• Remote control via addressable RS232 (standard) or GPIB (factory-fit option) interfaces.

• Closed case software calibration.

• Fully compliant with EN61010-1 Safety and EN61326 EMC standards.

† Licensed under U.S. Pat. 4,825,392

2

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 3

g

ACCURACY

Accuracies apply for 1 year 19°C to 25°C. Temperature coefficient outside these limits is <0.1 x
quoted range accuracy per °C.

DC Volts

Range Accuracy Resolution

Specifications

100mV

1000mV 0.04% ± 2 dig. 100uV

10V 0.06% ± 2dig. 1mV

100V 0.06% ± 2 dig. 10mV

1000V 0.06% ± 2 dig. 100mV

0.06% ± 3 di

.*

10uV

* after null

Input Impedance:

10MΩ//<100pF, except for Vdc plus Vac measurement when the
1MΩ ac attenuator is in parallel with the 10MΩ dc attenuator.

Maximum Input: 1kV DC or AC peak, any range.

NMR: >60dB at 50/60Hz.
1kΩ Unbalanced CMR:

>90dB at DC/50Hz/60Hz.

Maximum Allowable AC Voltage While Measuring DC Voltage

Range Max AC Range Max AC

100mV, 1000mV 6V 10V 80V (45Hz-50kHz) that can be applied without

100V 200V 1000V 1000V affecting the accuracy of the DC measurement.

The table shows the maximum AC voltage

AC Volts (True RMS)

Range Accuracy Resolution

45Hz - 10kHz 10kHz - 20kHz 20kHz - 50kHz

100mV 1% ± 20 dig. - 10µV

1000mV 1% ± 50 dig 100µV

10V 0.2% ± 20 dig 0.2% ± 20 dig 1% ± 80 dig 1mV

100V 1% ± 80 dig 10mV

750V - 100mV

Accuracy specifications apply for readings between 1,000 and 12,000 counts. Additional error at
crest factor = 3 typically 0.2%.

Extended frequency performance
(typical):

Input Impedance:

Maximum Input: 750V rms, 1000V peak; any range.
1kΩ Unbalanced CMR:

100mV range <-1dB at 50kHz; 1000mV, 10V and
100V ranges <-1dB at 100kHz.

1MΩ//<100pF

>60dB at DC/50Hz/60Hz

3

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 4

(AC + DC) Voltage Accuracy

Total measurement error will not exceed the sum of the separate ac and dc accuracy
specifications plus 1 display count.

Resistance

Range Accuracy Resolution

Maximum Input: 300V DC or AC rms, any range.

Maximum Open Circuit Voltage: 4V

DC Current

100Ω

1000Ω

10kΩ

100kΩ

1000kΩ

10MΩ

20MΩ

Range Accuracy Resolution

1mA 0.1% ± 3 dig. 100nA

100mA 0.1% ± 3 dig. 10uA

10A 0.3% ± 3 dig. to 1A 1mA

10A 1.0% ±3 dig. to 5A 1mA

10A 3% ± 10 dig to 10A 1mA

0.1% ± 3 dig.

0.08% ± 2 dig.

0.09% ± 2 dig.

0.09% ± 2 dig.

0.12% ± 2 dig.

0.5% ± 2 dig.

0.5% ± 2 dig.

10mΩ

100mΩ

1Ω

10Ω

100Ω

1kΩ

10kΩ

Maximum Input: mA ranges - 500mA DC or AC rms, 250V, fuse protected.

10A range - 10A DC or AC rms, 250V, fuse protected.

Typical Voltage Burden: mA ranges - <250mV

10A range - <500mV

AC Current (True RMS)

Range Accuracy (45Hz - 10kHz) Resolution

1mA 0.35% ± 20dig. 100nA

100mA 0.35% ± 20 dig. 10uA

10A 0.5% ± 20 dig. to 1A 1mA

10A 1.2% ± 20 dig to 5A 1mA

10A 3% ± 20 dig. to 10A 1mA

Accuracy specifications apply for readings between 1,000 and 12,000 counts. Additional error at
crest factory = 3 typically 0.2%.

Maximum Input: mA ranges - 500mA DC or AC rms, 250V, fuse protected.

10A range - 10A DC or AC rms, 250V, fuse protected.

Typical Voltage Burden: mA ranges - <250mV

10A range - <500mV

4

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 5

Frequency

Range: 10Hz to 100kHz

Input sensitivity: Better than 30m Vrms (100mV range); better than 10% of range

Capacitance

Range Accuracy Resolution

100Hz 0.01Hz

1000Hz 0.01% ± 1 dig. 0.1Hz

10kHz 1Hz

100kHz 10Hz

for all other Vac and Iac ranges.

Range Accuracy Resolution

10nF

100nF 100pF

1uF 2% ± 5 dig. 1nF

10uF 10nF

100uF 5% ± 5 dig. 100nF

Continuity and Diode Test

Continuity:

Diode Test: Test current approximately 0.5mA; displays voltages up to 1.2V.

Maximum Open Circuit
Voltage:

Maximum Input: 300V DC or AC rms, any range.

DISPLAY

Display Type: High contrast LCD. Main display 4½ digits 17mm high, secondary

Scale Length: 4¼ digits (12000 counts) in most modes.

Annunciators: LCD annunciators for all ranges, functions and program modes.

10pF

1000Ω range selected; audible tone sounds for impedance <10Ω.

4V

display 5 digits 10mm high.

Reading Rate: Varies with function, maximum 4/sec.

Overrange: Display flashes 12000 if input too great for range.

Overflow: Displays -Or- if calculated result overflows display.

COMPUTING FUNCTIONS

Null (Relative) Stores current reading and subtracts it from future readings.
Ω Null:

Hold: Reading is frozen

T-Hold (Touch & Hold): Reading is frozen when stable.

dB:

5

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 6

Additional non-volatile function for nulling test lead resistance.

Displays measurement in dBm relative to 600Ω or other user-entered
impedance.

AC plus DC: The RMS value of the ac plus dc parts of the signal is calculated and

% Deviation: Displays % deviation from entered reference value.

Ax+B: Linear scaling of results, with offset.

Limits: Reading displayed with HI, LO, or PASS with respect to user-defined

Min/Max: Minimum and maximum reading stored.

Power: Calculates V

VA: Calculates and displays Volts x Amps.

Data Logger: Manual or automatic storage of 100 measurements. Storage interval

INTERFACES

Full remote control facilities are available through the RS232 (all models) or GPIB (alternative
mains-only version) interfaces.

RS232: Baud rates 2400, 9600 or 19200. Complies fully with the ARC

displayed.

high and low limits.

2

/R and displays in Watts with respect to a user-defined

impedance.

1s to 9999s, manually from keyboard, or by remote contact closure.

(Addressable RS232 Chain) interface standard. Address selectable
from the front panel. Operational only when the meter is powered from
the AC input.

GPIB (IEEE-488): The meter can be specified with an IEEE-488 interface. This is an

alternative version which operates only from AC mains; IEEE-488 is
not a retrofittable option. Address selectable from the front panel.

POWER REQUIREMENTS

AC Input: 220V-240V or 110-120V AC ±10%, 50/60Hz, by internal adjustment;

5VA max. Installation Category II.

Batteries: 6 x C cells, disposable or rechargeable.

Battery Life: >150 hours from alkaline cells; typically 70 hours from rechargeable

cells.

GENERAL

Operating Range: +5°C to + 40°C, 20% to 80% RH

Storage Range:

Environmental: Indoor use at altitudes up to 2000m, Pollution Degree 1.

Safety: Complies with EN61010-1.

EMC: Complies with EN61326.

Size: 260(W) x 88(H) x 235(D)mm, excl. handle and feet.

−20°C to + 60°C

Weight: 2.0kg.

6

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 7

EC Declaration of Conformity

We Thurlby Thandar Instruments Ltd
Glebe Road
Huntingdon
Cambridgeshire PE29 7DR
England

declare that the

Model 1705 True RMS Programmable Multimeter and

Model 1705GP True RMS Programmable Multimeter with GPIB

meet the intent of the EMC Directive 89/336/EEC and the Low Voltage Directive 73/23/EEC.
Compliance was demonstrated by conformance to the following specifications which have been
listed in the Official Journal of the European Communities.

EMC

Emissions: a) EN61326 (1998) Radiated, Class B

b) EN61326 (1998) Conducted, Class B

c) EN61326 (1998) Harmonics, referring to EN61000-3-2 (2000)

Immunity: EN61326 (1998) Immunity Table 1, Performance B, referring to:

a) EN61000-4-2 (1995) Electrostatic Discharge

b) EN61000-4-3 (1997) Electromagnetic Field

c) EN61000-4-11 (1994) Voltage Interrupt

d) EN61000-4-4 (1995) Fast Transient

e) EN61000-4-5 (1995) Surge

f) EN61000-4-6 (1996) Conducted RF

Safety

Multimeter: EN61010-1
Installation Category I measurements to 1000V,
Installation Category II measurements to 600V,
Pollution Degree 1.

Probes: IEC1010-2-031
Rated to 1000V, Installation Category III.

CHRIS WILDING
TECHNICAL DIRECTOR

2 July 2004

7

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 8

Safety

This multimeter is a Safety Class I instrument according to IEC classification and has been
designed to meet the requirements of EN61010-1 (Safety Requirements for Electrical Equipment for
Measurement, Control and Laboratory Use). It is an Installation Category II instrument intended for
operation from a normal single phase supply.

WARNING! THIS INSTRUMENT MUST BE EARTHED WHEN OPERATED FROM A MAINS SUPPLY

Any interruption of the mains earth conductor inside or outside the instrument will make the
instrument dangerous. Intentional interruption is prohibited. The protective action must not be
negated by the use of an extension cord without a protective conductor.

When operated from the internal batteries the multimeter meets the safety requirements for a Safety
Class II (reinforced insulation) product and does not require grounding for safety.

The test leads supplied with this instrument meet the requirements of IEC1010-2-031 and are rated
to 1000V Cat III; use only these test leads with the meter or a set of equivalent performance.

This instrument has been tested in accordance with EN61010-1 and has been supplied in a safe
condition. This instruction manual contains some information and warnings which have to be
followed by the user to ensure safe operation and to retain the instrument in a safe condition.

This instrument has been designed for indoor use in a Pollution Degree 1 environment (no pollution,
or only dry non-conductive pollution) in the temperature range 5°C to 40°C, 20% - 80% RH (non-
condensing). It may occasionally be subjected to temperatures between +5° and −10°C without
degradation of its safety. It has been designed for Installation Category II measurement use to
600VDC/ACrms. and Installation Category I measurement use to 1000VDC/750VACrms. The full
definitions of Categories I and II can be found in IEC664, but the following can be taken as a guide:

Installation Category I is signal level e.g. telecommunication, electronic equipment, with smaller
transient overvoltages than Installation Category II.

Installation Category II is local domestic supply level, e.g. portable equipment and appliances. In
particular, Category II does not include distribution level supplies, e.g. three phase installations
which are classified as Installation Category III.

For this equipment 2500V is the maximum peak transient overvoltage that can be tolerated by any
terminal with respect to earth ground without impairing safety.

Use of this instrument in a manner not specified by these instructions may impair the safety
protection provided. Do not operate the instrument outside its rated supply voltages or
environmental range. In particular excessive moisture may impair safety.

When the instrument is connected to its supply or its inputs are connected to live voltages, terminals
may be live and opening the covers or removal of parts (except those to which access can be
gained by hand) is likely to expose live parts. The apparatus shall be disconnected from all voltage
sources before it is opened for any adjustment, replacement, maintenance or repair. Any
adjustment, maintenance and repair of the opened instrument under voltage shall be avoided as far
as possible and, if inevitable, shall be carried out only by a skilled person who is aware of the
hazard involved.

If the instrument is clearly defective, has been subject to mechanical damage, excessive moisture
or chemical corrosion the safety protection may be impaired and the apparatus should be withdrawn
from use and returned for checking and repair. Make sure that only fuses with the required rated
current and of the specified type are used for replacement. The use of makeshift fuses and the
short-circuiting of fuse holders is prohibited.

Do not wet the instrument when cleaning it and in particular use only a soft dry cloth to clean the
display window. The following symbols are used on the instrument and in this manual:

WARNING - risk of electric shock.

CAUTION - refer to accompanying documentation;
incorrect operation may damage the meter.

8

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 9

mains earth (ground)

direct current

alternating current

This instrument has been designed to meet the requirements of the EMC Directive 89/336/EEC.

Compliance was demonstrated by meeting the test limits of the following standards:

Emissions

EN61326 (1998) EMC product standard for Electrical Equipment for Measurement, Control and
Laboratory Use. Test limits used were:

a) Radiated: Class B

b) Conducted: Class B

c) Harmonics: EN61000-3-2 (2000) Class A; the instrument is Class A by product category.

Immunity

EN61326 (1998) EMC product standard for Electrical Equipment for Measurement, Control and
Laboratory Use.

Test methods, limits and performance achieved were:

a) EN61000-4-2 (1995) Electrostatic Discharge : 4kV air, 4kV contact, Performance B.

b) EN61000-4-3 (1997) Electromagnetic Field, 3V/m, 80% AM at 1kHz, Performance B.

EMC

c) EN61000-4-11 (1994) Voltage Interrupt, 1 cycle, 100%, Performance A.

d) EN61000-4-4 (1995) Fast Transient, 1kV peak (AC line), 0.5kV peak (DC Outputs),

e) EN61000-4-5 (1995) Surge, 0.5kV (line to line), 1kV (line to ground), Performance A.

f) EN61000-4-6 (1996) Conducted RF, 3V, 80% AM at 1kHz (AC line only; DC Output

According to EN61326 the definitions of performance criteria are:

Performance criterion A: ‘During test normal performance within the specification limits.’

Performance criterion B: ‘During test, temporary degradation, or loss of function or

performance which is self-recovering’.

Performance criterion C: ‘During test, temporary degradation, or loss of function or
performance which requires operator intervention or system reset occurs.’

Where Performance B is stated the multimeter will continue to function but accuracy may deviate
from Specification under the test conditions. However, the possible deviations are small and
infrequent and are unlikely to be a problem in practice.

Cautions

To ensure continued compliance with the EMC directive the following precautions should be
observed:

Performance B.

connections <3m not tested), Performance A.

a) only use screened cables and connectors to connect between the multimeter’s RS232

interface and other equipment.

b) after opening the case for any reason ensure that all signal and ground connections are

remade correctly before replacing the cover. Always ensure all case screws are correctly
refitted and tightened.

c) In the event of part replacement becoming necessary, only use components of an identical

type, see the Service Manual.

9

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 10

Mains Operating Voltage

Check that the instrument operating voltage marked on the rear panel is suitable for the local
supply. Should it be necessary to change the operating voltage, proceed as follows:

1) Disconnect the instrument from all voltage sources.

2) Unclip the front bezel by gently pulling the centre of each long edge up and forward.
The case halves are held together by 4 plastic push-rivets. Use the blade of a small

screwdriver in the slot beside each rivet to first ease out the rivet head and then fully remove
the rivet body. Separate the case halves. Visit www.tti-test.com

3) Change the transformer connections following the diagrams below:

Installation

for further details.

4) Reassemble in the reverse order.

5) To comply with safety standard requirements the operating voltage marked on the rear panel
must be changed to clearly show the new voltage setting.

Mains Lead

When a three core mains lead with bare ends is provided it should be connected as follows:-

WARNING! THIS INSTRUMENT MUST BE EARTHED WHEN OPERATED FROM AN AC LINE SUPPLY

Any interruption of the mains earth conductor inside or outside the instrument will make the
instrument dangerous. Intentional interruption is prohibited. The protective action must not be
negated by the use of an extension cord without a protective conductor.

Battery Operation

To fit or replace the six ‘C’ cells, slide off the battery cover at the rear of the instrument and
remove the battery tray. For safety reasons the battery cover can only be slid off after first
removing the security screw with a screwdriver. Always refit the security screw after changing the
batteries.

Brown - Mains Live

Blue - Mains Neutral

Green / Yellow - Mains Earth

10

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 11

Either rechargeable or disposable cells may be used; fit into the battery tray observing the polarity
marked in the tray. Suitable cells are as follows:

Rechargeable: 2 Amp hour, e.g. NCC200, AN220, VR2C, RSH1.8, P-180C.

Disposable: Alkaline, e.g. MN1400.

Zinc Carbon, e.g. R14B, R14S.

If batteries are fitted it is essential that the disposable/rechargeable selector switch on the rear
panel is positioned correctly before applying external power via the AC socket.

WARNING! If disposable batteries are fitted and the selector is set in the rechargeable
position, there is a risk of explosion if the meter is connected to an AC supply.

The Rechargeable batteries are charged at a ‘trickle’ rate of C/20; the time to fully charge from
completely discharged is approximately 28 hours.

Low battery condition is indicated by showing the battery symbol in the top left-hand corner of the
display; when this symbol shows, approximately 5% of battery life remains.

Handle

Adjust the handle position by pulling out the ends and rotating the handle to the desired position.
There are sixteen possible positions including five facing forward which provide upward tilts for
the most convenient bench operation. The handle may be swung out of the way to the back or
front of the instrument if no tilt is required. The natural spring in the handle will lock it into position
when the handle is released.

11

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 12

This section is a general introduction to the features and organisation of the multimeter intended
to be read before using the instrument for the first time. Detailed operation is covered in later
sections, starting with Making Basic Measurements.

Connections

Input Sockets

The input sockets are 4mm safety sockets on a 19mm pitch designed to accept 4mm safety plugs
with fixed or retractable shrouds. The sockets are all rated to 1000V (Cat I)/600V (Cat II) with
respect to earth ground.

The input impedance between V/Ω and COM is nominally 10MΩ on dc ranges and 1MΩ on ac
ranges. The black COM socket is considered less positive than the red socket.

The mA/10A current sockets are low impedance; the voltage burden between mA/10A and COM
at full scale is <250mV for the mA ranges and <500mV for the 10A range. The black COM socket
is considered less positive than the white mA/10A sockets.

Multimeter Test Leads

General Operation

RS232

The test leads supplied meet the requirements of IEC1010-2-031 and are rated to 1000V Cat III.
Use only the test leads provided, or a set of similar performance, to ensure safe operation.
Alternative test leads should be rated to at least 1000V (Cat I), 600V (Cat II) and 10A current
capability.

The RS232 interface only operates when the instrument is run from an ac supply; RS232 signal
ground is then connected to the safety ground. The interface is fully isolated from the
measurement system.

9-pin D-connector compatible with the Thurlby Thandar ARC (Addressable RS232 Chain) system.
The pin connections are shows below:

Pin Name Description
1 - Power to optional PC-02
2 TXD Transmitted data from instrument
3 RXD Received data to instrument
4 - No internal connection
5 GND Signal ground
6 - No internal connection
7 RXD2 Secondary received data
8 TXD2 Secondary transmitted data
9 GND Signal ground

Pin 2, 3 and 5 may be used as a conventional RS232 interface with XON/XOFF handshaking.
Pins 7,8 and 9 are additionally used when the instrument is connected to the ARC interface.
Signal grounds are connected to safety ground.

To ensure compliance with EMC legislation use only screened cable assemblies with screened
connectors when connecting to other equipment.

GPIB (IEEE-488)

An IEEE-488 interface is available on the alternative mains-only version; IEEE-488 is not a
retrofittable option. The GPIB connector is located on the rear panel together with the switch
which selects between RS232 and GPIB.

12

Telemeter Electronic GmbH | Joseph-Gaensler-Str. 10 | Phone [phone] | Fax [phone] | www.telemeter.info 13