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

5.6 Windows Command Language

The following section contains detailed de scriptions of each function of the Windows command language. Tho se commands that pe rtain to onl y the SM204 0 are indicated. Most functions return an error code. The code can e ither be retrieved as a st ring usin g DMMErrStri ng function, or looked up in the SM204032.H header file. The

UserDMM.H file contains a ll the pertinen t definitions for the DMM ranges functions etc. The following description for the various functions is based on “C” f unction declarations. Keep in mind that the Window s DLL containing these functions as sumes all int values to b e windows 32bit integers (corresponds to VisualBasi c long type). TRUE is 1 and FALSE i s 0 (which is also differe nt from VisualBasic where True is –1 and False is 0) .

DMMArmAnalogTrigger

SMX20 40 ; SM X20 44 ;

Description

Remarks

#include "sm2 04032.h"

int DMMArmAnalogTrigger(int nDmm, int iSamples, double FAR *dThresh)

This function is usable for VDC, VAC, Ohms, IAC, and IDC. Setup the SMX2040 for analog level trigger operation. Foll owing reception of this command the DMM makes m easure ments continuously, waiting for a value which exceeds the threshold, dThresh.

When this occurs, a trigger is produced with identical processing as in

DMM ArmTrigger. Threshold crossing sense is determined by the first measurement following the call o f DMMArmAnalogTrigger. If that measurement is lower than the set threshold, dThresh , subsequent measurements greater than dThresh will trigger the

DMM. If the first measurement is greater th an dThresh, subsequent measurements smaller than dThresh will trigger. For exam ple, if dThresh is 2.00000 V and the first reading after arming the D MM is 2.500000 V, then 1.999999 V (or smaller) will trigger the DMM. On the other hand, i f dThresh is 1.000000 V and the first reading after arming the DMM is 0.500000 V, then 1.000001 V (or gre ater) will trigger the DMM. example, in the 330 mV range, dThresh must be within -0.330000 and +0.330000. In the

33 k

Ω, range dThresh must be between 0.0 and 33.0e3.

Following an analog level trigger event, the DMM makes iSamples readings at the set function, range, and reading rate, and stores them in an internal buffer. Autoranging is not allowed when using DMMAnalogTrigger. Between the time the

DMMArmAnalogTrigger is issued and the time the buffer is read, no other com mand should be sent to the DMM. One exception is the DMMDisArmTrigger command.

Use the DMMReady to monitor when the DMM is ready. When ready, you can read up-to iSamples, using DMMReadBuffer or DMMReadBufferStr functions. Once DMMReady returns TRU E, it should not be used again prior to reading the buffer, since it prepares the buffer for reading when it detects a ready con dition.

51 Signametrics

Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com