Tektronix 3750 Primary User

Model 3750 Multifunction I/O Card

Keithley Instruments, Inc. Connection Instructions and Specifications

28775 Aurora Road

Cleveland, Ohio 44139
1-888-KEITHLEY
www.keithley.com

Introduction

This instruction sheet contains information about the Keithley Instruments Model Series 3700 Multifunction I/O Card
connector pins, safety precautions, and product specifications.

WARNING The following information is intended for qualified service personnel. Do not make module

connections unless qualified to do so.

To prevent electric shock that could result in serious injury or death, adhere to th e following

safety precautions:

Before removing or installing a switch module in the mainframe, make sure the mainframe is

turned off and disconnected from line power.

Before making or breaking connections, make sure the power is removed from all external

circuitry.

Do not connect signals that may exceed the maximum specifications of the model or

external wiring. Specifications for each circuit board are provided in the Series 3700 User's
Manual.

WARNING All wiring must be rated for the maximum voltage in the system. For example, if 300V is

applied to the backplane connector, all module wiring must be rated for 300V.

Information related to reading, writing, and controlling channels, as well as scanning, can be found in the Series
3700 System Switch/Multimeter User’s Manual. Detailed information about controlling the Series 3700 from a
remote interface can be found in the Series 3700 System Switch/Multimeter Reference Manual.

PA-981 Rev. A / July 2008 1

Model 3750 Multifunction I/O Card

Model 3750 Multifunction I/O Card

The Model 3750 Multifunction I/O Card has 40 bidirectional digital I/O bits arranged in five banks of eight bits each.
Each bank can be configured as either inputs or outputs. One bank of I/O is equivalent to one system channel.

The two analog outputs of the Model 3750 can be individually configured as either voltage outputs (+/- 12 V) or as
current outputs (0 mA to 20 mA or 4 mA to 20 mA).

Four 32-bit counters are provided with a maximum input range of 1 MHz. Each counter has a gate input for control
of event counting.

Figure 1: Model 3750 Multifunction I/O Card

2 PA-981 Rev. A / July 2008

Model 3750 Multifunction I/O Card

Connection information: Model 3750

Figure 2: Model 3750 connection information

PA-981 Rev. A / July 2008 3