Agilent Technologies 66lxxA manual Outpttltsour

Table 5-1. Trigger Subsystem Status and Event Signals

Signal

DWE

LSC

RTG

TDC

STC

STS

WTG

Type

Status Bit

Event Handle

Event Handle

Event Handle

Event Handle

Event Handle

Status Bit

Description

Dwelling. True only during the dwelling state. DWE can be monitored at the Operation Status register (see "Chapter 4 - Status Reporting").

List Sequence Complete. Occurs upon exit from the Dwelling state after the last programmed list point has been executed. If LIST: COUNt is greater than 1, LSC occurs once for each count until the list is done.

Received a trigger. Occurs upon exit from the Initiated state.

Trigger delay complete. Occurs upon exit from the Delaying state.

Step Completed. Occurs upon exit from the Dwelling state.

Step Started. Occurs upon transition into the Dwelling state.

Waiting for trigger. True only when the trigger subsystem is in either the Initiated or the Delaying state. WTG can be monitored at the Operation Status register (see "Chapter 4 - Status Reporting”).

Trigger In and Trigger Out

The mainframe has two bnc connectors labeled Trigger In and Trigger Out. Figure 5-2 shows the model for these signals, which are applied to all power modules in the mainframe (see “TrigIn/TrigOut Characteristics” in Chapter 1 of Agilent 66000A Installation Guide for electrical parameters). Trigger In and Trigger Out are electrically isolated at each power module from the mainframe chassis reference ground.

Trigger In

Trigger In is a TTL level input that can be selected as a trigger source for each module. Modules recognize a Trigger In signal on its falling edge. Trigger In is selected as a trigger source with the EXTernal parameter. For example:

TRIGger:SOURce EXT

OUTPut:TTLT:SOURce EXT

Trigger Out

The Trigger Out signal is a 20-microsecond, negative-true TTL pulse. This pulse can be driven by each power module by programming the OUTPut:TTLTrg commands. Each module can also select Trigger Out as a trigger source by programming the SCPI TRIGger:SOURce TTLT command (see "Chapter 3 - Language Dictionary" for details of these commands).

∙To select the Trigger In connector as a trigger source, use TRIG: SOUR EXT

∙To apply a trigger to the Trigger Out connector, use OUTP:TTLT ON. You must also select the source

(OUTP:TTLT:SOUR).

Figure 5-2. TTLT Trigger Model

60 Synchronizing Power Module Output Changes