User`s guide

Installation - 3

NOTE: It is good engineering practice to twist and shield all signal wires to and from the digital

connectors. If shielded wire is used, connect only one end of the shield to chassis ground

to prevent ground loops.

Figure 3-4 shows how you can connect the FLT/INH circuits of the dc source.

In example A, the INH input connects to a switch that shorts the Inhibit pin (+) to common whenever it

is necessary to disable output of the unit. This activates the remote inhibit (RI) circuit, which turns off

the dc output. The front panel Prot annunciator comes on and the RI bit is set in the Questionable Status

Event register. To re-enable the unit, first open the connection between pins INH + and common and

then clear the protection circuit. This can be done either from the front panel or over the GPIB/RS-232.

In example B, the FLT output of one unit is connected to the INH input of another unit. A fault

condition in one of the units will disable all of them without intervention either by the controller or

external circuitry. The controller can be made aware of the fault via a service request (SRQ) generated by

the Questionable Status summary bit. Note that the FLT output can also be used to drive an external relay

circuit or signal other devices whenever a user-definable fault occurs.

FLT

Output

INH

Input

B) FLT Example with Multiple Units

FLT

Output

INH

Input

Switch

(Normally

Open)

INH Common

INH Input

A) INH Example with One Unit

INH FLT

. . . .

INH FLT

. . . .

NOTE: Connectors

are removable

+ - +

4321

Figur

e 3-4. FLT/INH Examples