Tektronix 7703 User manual

Keithley Instruments

28775 Aurora Road
Cleveland, Ohio 44139
1-800-935-5595

tek.com/keithley

Model 7703 Multiplexer Module

Instructions for use with DAQ6510

077144800 / April 2018 *P077144800* 1

Introduction

The 7703 32-Channel High-Speed Differential Multiplexer Module offers 32 channels of 2-pole or 16 channels
of 4-pole multiplexer switching that can be configured as two independent banks of multiplexers. The
nonlatching reed relays provide high speeds and are designed for 300 V, 500 mA; 10 VA. The relay closures
are stored in onboard memory. The 7703 is ideal for RTD and thermistor temperature applications.

Figure 1: Model 7703 32-Channel High-Speed Differential Multiplexer Module

Item shipped may vary from model pictured here.

Model 7703 Multiplexer Module Instructions for use with DAQ6510

2 077144800 / April 2018

The 7703 includes the following features:

▪ Two-wire or four-wire resistance measurements (automatically pairs switches for four-wire

measurements—n + 16)

▪ Two 50-pin D-sub connectors for use with the Model 7788 50-Pin D-Subminiature Connector Kit
▪ Temperature applications (RTD or thermistor)
▪ High-speed, non-latching reed relays (relays go to open state after power is removed or after

System Reset)

▪ Model 7788 50-Pin D-Subminiature Connector Kit, which includes two D-sub connectors.

The 7703 can be used with the DAQ6510 Data Acquisition and Multimeter System.

If you are using this switching module with the 2700, 2701, or 2750, please see Model 7700, 7702,
and 7703 Multiplexer Modules User's Guide, Keithley Instruments document number PA-695.

Connections

The following information describes how to make connections to the switching module and define the channel
designations. A connection log is provided that you can use to record your connections.

Connection and wiring procedures in this document are intended for use by qualified
personnel only. Do not perform these procedures unless qualified to do so. Failure to
recognize and observe normal safety precautions could result in personal injury or death.

Module connections

Do not attempt to perform this procedure unless qualified to do so. Failure to recognize and
observe normal safety precautions could result in personal injury or death.

Do not exceed the maximum specifications for the 7703 switching module. Refer to the
specifications provided in the data sheet. Failure to recognize and observe normal safety
precautions could result in personal injury or death.

When you are looking at the rear connectors of the 7703 switching module, the connector on the left is P1017
and the connector on the right is P1016.

Figure 2: Model 7703 Pinouts (P1017 and P1016)

Model 7703 Multiplexer Module Instructions for use with DAQ6510

077144800 / April 2018 3

Make connections to the Model 7788 50-Pin D-Sub Connector Kit using the correct wire size (up to 20 AWG).
Add supplementary insulation around the harness for voltages above 42 V

PEAK

, as shown in the following figure.
Refer to Model 7788 50-Pin D-Sub Connector Kit Connection and Wiring Information, Keithley Instruments
document PA-687, for specific wiring instructions.

All wiring must be rated for the maximum voltage in the system. For example, if 1000 V is
applied to the front terminals of the instrument, the switching module wiring must be rated
for 1000 V. Failure to recognize and observe normal safety precautions could result in
personal injury or death.

A connector cover must be installed on an unused D-sub connector. If the connector is left
open, an electrical shock hazard may be present. Failure to recognize and observe normal
safety precautions could result in personal injury or death.

Figure 3: Covering an unused connector

Model 7703 Multiplexer Module Instructions for use with DAQ6510

4 077144800 / April 2018

Channel designations

P1017

P1016

Pin

CH

Pin

CH

Pin

CH Pin

CH

Pin

CH

Pin

CH

18

9 HI

30

15 HI

42

29 HI

1

Sense HI

26

5 HI

38

19 HI

19

9 LO

31

15 LO

43

29 LO

2

Sense LO

27

5 LO

39

19 LO

20

10 HI

32

16 HI

44

30 HI

4

Input HI

28

6 HI

40

20 HI

21

10 LO

33

16 LO

45

30 LO

6

Input LO

29

6 LO

41

20 LO

22

11 HI

34

25 HI

46

31 HI

18

1 HI

30

7 HI

42

21 HI

23

11 LO

35

25 LO

47

31 LO

19

1 LO

31

7 LO

43

21 LO

24

12 HI

36

26 HI

48

32 HI

20

2 HI

32

8 HI

44

22 HI

25

12 LO

37

26 LO

49

32 LO

21

2 LO

33

8 LO

45

22 LO

26

13 HI

38

27 HI

22

3 HI

34

17 HI

46

23 HI

27

13 LO

39

27 LO

23

3 LO

35

17 LO

47

23 LO

28

14 HI

40

28 HI

24

4 HI

36

18 HI

48

24 HI

29

14 LO

41

28 LO

25

4 LO

37

18 LO

49

24 LO

Schematic diagram

The simplified schematic diagram of the 7703 is shown in the following figure.
Channels 1 to 32 are used for all measurements.
There are two backplane relays (channels 33 and 34) to connect the input channels to the backplane of the

instrument. With a 2-wire function selected, channel 33 closes. With a 4-wire function selected, channels 33
and 34 close.

There is a 2-pole/4-pole relay (channel 35) between channels 1 to 16 and channels 17 to 32. When a 2-wire
function (such as DCV) is selected, channel 35 closes (2-pole position) to allow any of the 32 channels to be
connected to the input backplane.

When a 4-wire function is selected, channel 35 opens (4-pole position) to isolate channels 1 to 16 from
channels 17 to 32. When one of the channels 1 to 16 is closed, its paired channel (17 to 32) also closes to
connect the sense channel to the sense backplane.

The Input and Sense terminals are connected to the inputs of channels 33 and 34 (isolation relays).

Channels 33 to 35 in this schematic refer to designations used for control and not actual available
channels. For more information, refer to the applicable instrument reference manual.