User manual

Using the Relay Multiplexer 39Chapter 2

Example: Switching

Channels (Two-Wire)

This example illustrates two-wire mode operation. The HI and LO terminals

of bank 0 channels 0 and 7 are closed, connecting them to the bank 0 HI and

LO COM terminals. Figure 2-2 shows how the multiplexer is configured.

For two-wire operation, the control relays are set as follows. 0990/0991 are

opened if using the <channel_list> command with SCAN:PORT ABUS and

SCAN:MODE <mode>. Mode can be RES, VOLT, or NONE. 0990/0991 are

left in their present state if mode is FRES. 0992/0993 will close when

SCAN:PORT ABUS is selected during a scan (see “Scanning Channels”).

0994/0995/0996 remain in their present state with the following exceptions.

0994 is closed in RES mode. If <card_number>, WIRE2X64 (2x64

configuration), 0994 is closed in the RES and NONE modes. In the FRES

mode, 0994 and 0995 are opened. 0996 closes and connects COM to LO

for voltage measurements with the MEASure or SCPI commands in a

scanning multimeter.

Figure 2-1. Example: Switching Channels (One-Wire)

Open

Closed

CH0991

CH0990

Closed

Open

CH0995

JM5JM4

JM2 JM3

COM

CH1

1W H

Cable T

1W L

1W Ref L

1 Wire High Common

Cable Test

1 Wire Low Common

1 Wire Low Ref

Bank 2

SWITCH CARD

TERMINAL MODULE