Daqadccalctrig, Daqadcdisarm – Measurement Computing WaveBook rev.3.0 User Manual

Page 200

D-4 daqX API - Command Reference,

6-24-99

WaveBook User’s Manual

daqAdcCalcTrig

DLL Function

daqAdcCalcTrig(DaqHandleT handle, BOOL bipolar, FLOAT gainVal, FLOAT voltageLevel,

PWORD triggerLevel);

daqAdcCalcTrig(DaqHandleT handle, BOOL bipolar, FLOAT gainVal, FLOAT voltageLevel,

PWORD triggerLevel);

Visual BASIC

VBdaqAdcCalcTrig&(ByVal handle&, ByVal bipolar&, ByVal gainVal!, ByVal

voltageLevel!, triggerLevel%)

Delphi

daqAdcCalcTrig(handle:DaqHandleT; bipolar:longbool; gainVal:single;

voltageLevel:single; var triggerLevel:DWORD)

handle

Handle to the device for which the trigger level is to be calculated

bipolar

A flag that should be non-zero if the trigger channel is bipolar, or zero if it is unipolar

gainVal

A gain value of the trigger channel

voltageLevel

Voltage level to trigger at.

Parameters

triggerLevel

Returned count to program the trigger using the daqAdcSetTrig function

Returns

DerrNoError

No error (see the API Error Codes table at the end of this chapter).

See Also

daqAdcSetTrig

Program References

None

Used With

All devices

Description

daqAdcCalcTrig

calculates the trigger level and source for an analog trigger. The result of daqAdcCalcTrig is the triggerLevel

parameter. The triggerLevel parameter can then be passed to the daqAdcSetTrig function to configure the analog trigger.

The triggerLevel parameter is calculated from: the unipolar/bipolar and gain settings of the trigger channel, the desired analog voltage
setpoint and trigger polarity, and the external reference voltage of D/A channel 1. The trigger channel is automatically the first channel in
the current A/D scan group for DaqBooks and DaqBoards.

The bipolar parameter should be set according to the current bipolar/unipolar setting of the trigger channel. This parameter is jumper-
selectable when using a DaqBook/100/112 and DaqBoard/100A/112A and software-programmable when using the DaqBook/200/200A.

The gainVal parameter sent to the daqAdcCalcTrig should be the actual gain of the trigger channel, not the gain definition used by the
rest of the Daq* A/D functions. For example, if the trigger channel uses the gain definition DgainX8, the gain parameter of
daqAdcCalcTrig

should be 8.

The voltageLevel defines the analog voltage at which the Daq* will trigger. The setpoint must be within the valid input range of the
trigger channel. For example, the setpoint range for a bipolar channel with unity gain would be 0 to 10 V (for ×8 gain, the range would be 0
to 1.25 V) for a DaqBook or a DaqBoard.

Note: When using the Daq PCMCIA, the bipolar parameter is ignored.

daqAdcDisarm

DLL Function

daqAdcDisarm(DaqHandleT handle);