DMMBurstRead. Artison SMX2040, S-LCR-DM, SMX2042, SMX2044

DM MBur stBuffRead(0, 4, 50); // 4 settling readings for each

// measurement, and take 50 readings wh ile( ! DMMReady(0) ); o 50 ; i++)

// wait for completion

// read 64 readings from DMM’s

// on-board b uffer

Buffer[i] = DMMReadBuffer(0);

DMMBurstRead

SMX2040 ; SMX2042 ; SMX2044 ;

Description Setup the DMM for multiple read ings operation, sending back measurements as they come.

#inc lude "sm2 04032.h"

#inc lude "User DMM.h"

Remarks Set the DMM to take multiple measurements, sendi ng readings back to the computer.

This function is similar to th e DMMSetTrigRead function, with the exception that it does not wait for a hardware trigger to start making measurements. Following reception of this c omman d the DMM enters a burst read mode, where it takes iSettle + 1 readings at the se t measu rement functio n, range, and reading rate; and sends the last reading to the computer. This process repeats for iSamples. Following the issue of this command, and until iSa mpels measur ements are read, it is necessary to read the samples from the DMM using the DMMReadMeasurement command as fast as they become available . This will prevent an Overrun communication error, which is an indication that the ra te at which measurements are read from the bus do not keep up with the DMM transmission.

The DMM has five readings FIFO to lessen this problem. No autoranging is allowed in this mode. This function is usable for VDC, VAC, Ohms, IAC, IDC, and RTD measurements. Measur ement rate should be set to 10rps or higher. The total time it takes to com plete this process is equal to iSamples * ( iSettle + 1) / (measurement rate).

Use the DMMRead Measurement to monitor when reading becomes available, and to read the data. Read as many samples as iSamples to guarantee proper conclusion of this capture process.

Parame ter Type/Description nDmm int Identifies the DMM. DMMs are numbered st arting with zero. iSettle int The number of settling measurements prior to read value. Must be set between 0 and 250. Recommended value is 4.

Return Value iSamples int The number of samples the DMM takes following the sam e number of trigger pulses. This number must be between 1 and 32,000, inclusive.

The return valu e is one of the following constants.

Value Meaning

DMM_OKAY Operation successfully terminated

Negative Value Error code.

Reading [250];

DMMBurstRead(0, 10, 250); // settle 10 reads., 250 samples for(i=0; i < 250 ; i++) // read 250 meas. as they come

Signametrics 54

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