3Operating and Programming

DMM

Input

Channels

Common Terminals

(COM)

H

L

Figure 3-13. Scanning with External Instruments.

Figure 3- 14 shows the connections required to make a series (scan) of two- wire measurements (e.g. ohms, DCV) using ABus1 of the L4421A .

Sequence The L4421A outputs a Channel Closed pulse on pin 5 of its Ext Trig connector when a relay is closed and has fully settled (including any channel delay). By connecting this pin to the DMM’s external trigger (Ext Trig) input, the DMM is triggered to take a measurement. When the measurement is complete, the DMM outputs a pulse from its DMM (VM Complete) output. Connecting this output to pin 1 (Channel Advance) of the L4421A’s Ext Trig connector advances the scan and closes the next channel in the scan list.

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L4400 User’s Guide

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Agilent Technologies L4400 manual Input, Channels, Common Terminals