BS2p40 Controlling Test EQ over RS232 using SEROUT

JPL · 2011-05-13 11:19

PC <=> BS2p40 <=> Keithley PicoAmmeter

I am using the Parallax Professional Development board. The normal/main/programmable serial port is connected to the PC. I am using Pins 0-3 to connect to the dev board's RS-232 port which offers an IC to handle the voltage changes.

I am unable to send ANY information to or from the meter. Via hyperterminal I can configure, test, and read data from the device. Below is a simple program I've written. When I connect a 2nd serial cable to the port to display in a 2nd hyperterminal window I see what I expect. However when I connect it back to the Keithley nothing happens, not even an error on the Keithley display.

My question is, what am I doing wrong? Pin 0 of the dev. board is connected to "RX" and pin 2 is connected to "TX". CTS, and RTS are no connected.

Keithley setup:
RS-232
Baudrate: 1200
Flow: None
Parity: None
Bits: 8
TX Term: LFCR

Program:

' {$STAMP BS2p}
' {$PBASIC 2.5}
'-------------[I/O Begin]-----------
'-------------[I/O End]-------------
'-------------[Variables/Constants Begin]----------
idx           VAR   Word
current       VAR   Word
deci          VAR   Word
exponent      VAR   Word
'-------------[Variables/Constants End]------------
'-------------[Main Program Begin]-----------
main:
Do
  DEBUG CR,LF,"Sending Read Command "
  SEROUT 2, 2063,100, [":READ?",LF,CR]    ' :READ? Command to read current
  DEBUG CR,LF,"Sent!"
  ' Example of current readout: +1.234567E-09A
  SERIN 0, 2063, 10000, readerror, [WAIT("+"), DEC current, WAIT("."), DEC5 deci, WAIT("E-"), DEC exponent]
  DEBUG CR,LF,DEC current,".",DEC deci,"E-",DEC exponent
LOOP

readerror:
DEBUG CR,LF,"Read Error!!!"
GOTO main

END
'-------------[Main Program End]-------------
'-------------[End of File]-------------

JPL · 2011-05-13 12:09

Fixed. A null modem was required. Simply swapping the wires from the pins to TX and RX were not enough. I blame the IC on the dev board.

BS2p40 Controlling Test EQ over RS232 using SEROUT

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