Closed Loop Calibration Automatic Calibration Using ProCal

CLOSED LOOP CALIBRATION – Overview  ProCal can control and readback from instruments connected using RS232 or GPIB interfaces.  An easy to use command language allows instrumentation to be set to the correct range and readings to be automatically fetched, processed and displayed on screen. ProCal Command Language

CLOSED LOOP CALIBRATION – Control  Using simple keywords, ProCal can send commands to an instrument : To communicate using the RS232 interface use : COM1 = carriage return, alternatively use for line feed To communicate using the GPIB interface use : Where address is simply the GPIB address

CLOSED LOOP CALIBRATION – Readback  Using simple keywords, ProCal can read back data from an instrument : To fetch a reading into memory use : Eg. For an HP34401A on COM1 the command is COM1 READ? This triggers the meter to take a reading To put this value in the computer memory, use UUT FETCHREAD To use the value in memory as the reading use UUT MEAS=READ

CLOSED LOOP CALIBRATION – Pre/Post Commands  ProCal allows commands to be sent either before a test begins, or at the end of a test  PRE-TEST Command Window This can be used to set up an instrument to the correct range / output, set a remote operation switch box to the correct state etc.  POST-TEST Command Window This can be used to set an instrument to a standby state or recalculate a calibration constant to update an instrument.

CLOSED LOOP CALIBRATION – Advanced Functions  ProCal can now manipulate numbers in memory and allow these to be manipulated with formulas to calculate, for example, calibration factors.  SHOWMSG : Display a message box during command execution  HIDEMSG: Force message to hide (message is hidden after all commands are run)  SOUND : Play a.WAV sound file  NOM=READ: Set the test NOMINAL value to the READING (obtained from RS232/GPIB)  MEAS=READ: Set the test MEASURED value to the READING (from RS232/GPIB)  CF=READ: Set the CAL FACTOR variable to the READING (from RS232/GPIB)  CALCREAD : Use a formula to modify the READING variable  CALCCF : Use a formula to modify the CAL FACTOR variable  TRIMREAD : Remove user defined leading / trailing chars from READING variable  TRIMCF : Remove user defined leading / trailing chars from CAL FACTOR variable  EXTRACTREAD : Extract a user defined string of characters from READING variable  EXTRACTCF : Extract a user defined string of characters from CAL FACTOR variable  FORMATCF : Format the CAL FACTOR variable with a user defined image  FORMATREAD : Format the READING variable with a user defined image  RESTART: Restart the current test  GOTO : Goto a specific test