Omega OMB-DAQBOARD-500 User Manual

DaqBoard/500 Series 

988994

 

Software and Board Operation     4-5 

 

 

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: 

o

  Software 

o

  External Gate (ADTRGIN) 

o

  External Trigger  (ADTRGIN) 

 

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

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. 

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).