60 Synchronizing Power Module Output Changes
Table 5-1. Trigger Subsystem Status and Event Signals
Signal Type Description
DWE Status Bit Dwelling. True only during the dwelling state. DWE can be monitored at the
Operation Status register (see "Chapter 4 - Status Reporting").
LSC Event Handle 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.
RTG Event Handle Received a trigger. Occurs upon exit from the Initiated state.
TDC Event Handle Trigger delay complete. Occurs upon exit from the Delaying state.
STC Event Handle Step Completed. Occurs upon exit from the Dwelling state.
STS Event Handle Step Started. Occurs upon transition into the Dwelling state.
WTG Status Bit 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