Using Scan Lists And External Trigger Input; Scan Lists; Figure 8-2, External Trigger In And External Trigger Out - Racal Instruments 1256E Manual

Switching system

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1256E User Manual

Using Scan Lists

and External

Trigger Input

read it. Any delay over 10 milliseconds rounds the delay to the

nearest 10 milliseconds.

Trigger In/Out Electrical Characteristics

Logic levels: TTL

Trigger In Input Impedance: 10 K-ohms

Trigger Out Drive Current: Sink/Source 4 mA

A scan list allows you to specify a list of switching commands to be

performed. Once you have defined this list, the 1256 will

automatically sequence through the scan list, executing one

command each time it detects a trigger pulse at the external trigger

input of the SYNC/TRIG connector.

Three types of commands may be entered into a scan list:

•

Close a specific relay

•

Recall a state stored in a non-volatile memory location

•

Break (stop scan list processing)

The 1256 may be programmed to sequence through a list of

channels. This feature is known as a "Scan List".

When a Scan List is used, the user defines a list of channels to

operate. Each time a trigger is received by the 1256, the presently

closed channel is opened, and the next channel on the list is

closed. This capability may be used in conjunction with a Digital

Multimeter (DMM) or other measurement device to allow a group

of measurements to be made without having to program the 1256

for each relay operation.

For example, without the Scan List feature, for each DMM reading,

you must:

Advanced SCPI Operations 8-13

Trigger In

Trigger Out

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