Omega OMB-DAQBOARD-500 Starting Triggering an ADC Acquisition, ADC Software, ADC External Gate

Starting (Triggering) an ADC Acquisition

There are several methods that can be used to initiate an acquisition, all of these are achieved by triggering or gating the ADC clock as mentioned previously. Note that a trigger is an edge active event and a gate is a level controlled enable.

An acquisition can be initiated via the following:

oSoftware

oExternal Gate (ADTRGIN)

oExternal Trigger (ADTRGIN)

ADC Software

Software can be used to start and stop the on-board ADC pacer clock.

ADC External Gate

An ADC clock may be “switched On” (and Off) with the external ADTRGIN input. The input is level sensitive and selectable as either active high or active low control. If the on-board pacer clock drives the ADC, the external gate input is used to enable and disable the ADC’s pacer clock after being polarity conditioned. The ADC clock will be enabled as long as the gate input is in the active state.

ADC External Trigger

The external gate/trig input (ADTRGIN) may also be configured as a rising or falling edge sensitive input to trigger the start of the ADC clock. External triggers are ignored until the ADC is enabled. Once the ADC is enabled, the next active edge signal on ADTRGIN will enable the ADC Clock source. To disable the clock, refer to the following section, Stopping an ADC Acquisition (CLOCK).

DaqBoard/500 Series 988994 Software and Board Operation 4-5