Calibrator
Remote Program Examples
41
Take a Thermocouple Measurement
This program takes one temperature measurement at a time.
10 REM Set Bus Timeout to 20 seconds, Init IEEE Bus
20 TIMEOUT 20 * 1000
30 INIT PORT 0
40 CLEAR @4
100 REM Reset 5560A, TC measurement mode
110 PRINT @4,”*RST; TC_TYPE J; TC_MEAS FAR”
200 PRINT “Hit Carriage Return to take a Reading”
210 INPUTLINE A$
220 REM Request the measurement value
230 PRINT @4, “VAL?”
240 REM Read measurement, unit
250 INPUT @4, M,U$
260 GOTO 200
Input Buffer Operation
As the Calibrator receives each data byte from the controller, it places the bytes in a portion of memory
called the input buffer. The input buffer holds up to 350 data bytes and operates in a first in, first out
fashion.
IEEE-488 The Calibrator treats the EOI IEEE-488 control line as a separate data byte and inserts it into
the input buffer if it is encountered as part of a message terminator. Input buffer operation is
transparent to the program running on the controller. If the controller sends commands faster than the
Calibrator can process them, the input buffer fills to capacity. When the input buffer is full, the
Calibrator holds off the IEEE-488 bus with the NRFD (Not Ready For Data) handshake line. When the
Calibrator has processed a data byte from the full input buffer, it then completes the handshake, which
allows the controller to send another data byte. The Calibrator clears the input buffer on power-up and
on receiving the DCL (Device Clear) or SDC (Selected Device Clear) messages from the controller.
RS-232 Under RS-232-C serial port remote control using ^S (<Cntl> S) XOFF protocol, the Calibrator
issues a ^S XOFF when the input buffer becomes 80 % full. The Calibrator issues a ^Q (<Cntl> Q)
when it has read enough of the input buffer so that it is <40 % full. With RTS (Request to Send)
protocol (selected as part of the RS-232 Port Setup Procedure), the serial interface asserts and
unasserts RTS in response to same conditions as for XON/XOFF protocol.
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