Model 7002Switch System Instruction Manual - Advanced Test ...

IEEE-488 ReferenceWith the Manual control source selected (:TRIGger:SOURce MANual), the instrument will wait until the frontpanel STEP key is pressed. Note that the Model 7002 mustbe taken out of remote (press LOCAL key or send LOCAL707 over bus) before it will respond to the STEP key. The:SYSTem:PRESet command also selects the Immediate controlsource.With the Bus control source selected (:TRIGger :SOURceBUS), the instrument will wait until a bus trigger is received(GET or *TRG). With the External control source selected(:TRIGger:SOURCE EXTernal), the instrument will waituntil an input trigger (via EXTERNAL TRIGGER connectoron rear panel) is received. With the Trigger Link controlsource selected (:TRIGger:SOURce TLINk), the instrumentwill wait until an input trigger is received (via TRIGGERLINK). With the Hold control source selected (:TRIGger:SOURce HOLD), the instrument will not respond to any ofthe control source events.After the programmed channel event is detected, the instrumentwill wait for the programmed Delay to time out. The:TRIGger:DELay command is used to set the Delay(where n = 0 to 999999.999 seconds).The *RST and :SYSTem:PRESet commands set the Delay tozero seconds.As can be seen in the flowchart, there are three paths that allowoperation to loop around the control source. Two of thesepaths also loop around the Delay. These three paths are describedas follows:1. When the Source Bypass is enabled (:ARM :TCONfigure:DIRectionSOURce) and the External or TriggerLink control source is selected, operation will looparound the control source on the initial pass through theTrigger Layer. If programmed to scan another channel,(channel count > 1), the bypass loop will not be in effecteven though it will still be enabled. The Source Bypassloop will reset (be in effect) if operation goes back toArm Layer 2.2. Each time the :TRIGger:IMMediate command is sent,operation will loop around the control source and theDelay. It is used when you do not wish to wait for a programmedchannel event to occur (or when the Hold controlsource is selected).3. Each time the :TRIGger:SIGNal command is sent, operationwill loop around the channel control source. Thispath functions the same as :TRIGger:IMMediate exceptthat it does not loop around the Delay.At this point the first (or next) channel in the Scan List willbe scanned (Device Action). When scanning channels, theprevious channel will open and the next channel will close(break-before-make). Also included in the Device Action isthe internal settling time delay for the relay and any additionalprogrammed settling time delay using the :STIMe commandof the :ROUTe Subsystem (see paragraph 5.13).After a channel is scanned, an Output Trigger will occur. Ifthe channel control source is programmed for Immediate,Manual, Bus or Timer, the output trigger pulse will be availableat the CHANNEL READY connector. If the TriggerLink control source is selected, Output Trigger action willoccur as follows:1. If the asynchronous Trigger Link mode is selected, theoutput trigger pulse will be available on the programmedTRIGGER LINK output line.2. If the semi-synchronous Trigger Link mode is selectedand the Source Bypass is disabled (:trig :tcon:dir acc),the Trigger Link line will be released (goes high).3. If the semi-synchronous Trigger Link mode is selectedand the Source Bypass is enabled (:trig :tcon:dir sour),the Trigger Link line will be pulled down low and thenreleased.Note: See paragraph 4.17 for details on using the TriggerLink.After a channel is scanned and an output trigger occurs, theinstrument will (if programmed to do so) return to the beginningof the trigger layer to scan another channel. The :TRIGger:COUNt command is used to set the channel count toa finite value (where = 1 to 9999) or for a continuousscan of the Scan List ( = INF). The :TRIGger:COUNt:AUTo ON command is used to automatically set the channelcount to the length of the Scan List. The *RST command setsthe channel count to one and the :SYSTem:PRESet commandenables the automatic channel count.5-28