I am making use of Prologix GPIB-USB Controller to be used in LISTEN ONLY mode (Device Mode) to decipher data communication between Two instruments namely Tester & Prober. I have written a sample program in python using Pyserial Module for this purpose.
The issue am facing is that i am able to see the Command and Response communicated between instruments , but cannot listen to the SRQ Signal send over GPIB bus. I am totally new to this area of GPIB programming and have very little knowledge about related stuff.
import os.path
import serial
import sys
from time import sleep
comport = '/dev/ttyUSB0'
# addr = '5'
ser = serial.Serial()
try:
ser = serial.Serial( comport, 9600, timeout=0.5 )
# Switch to DEVICE mode
cmd = '++mode 0'
print('Sending:', cmd)
cmd = cmd + '\n'
ser.write(cmd.encode('UTF-8'))
# Set instrument to LISTEN ONLY mode
cmd = '++lon 1'
print('Sending:', cmd)
cmd = cmd + '\n'
ser.write(cmd.encode('UTF-8'))
# Read the Data from GPIB BUS
while(True):
s = ser.read();
if len(s) > 0:
print(s)
except(serial.SerialException, e):
print(e)
f.close()
except(KeyboardInterrupt, e):
ser.close()
f.close()
I am running this code from a Raspberry Pi connected to one end of GPIB-USB Controller and other half connected to GPIB BUS (Connected to both Tester and Prober).
I am able to see all the commands transmitted from Tester and also response for those commands from Prober , But for certain commands the Prober reply back with a SRQ Code , But that is not visible in the Data output collected by this setup.
Output Collected:
F
PN0
?V
PN00453 ,Rzz00-R014.08R,P12,0000000000000000
a
020020
f1
000.0
G
COTBIRD-5S-2CPB-NL
T (Missing SRQ Reply for this Command)
O
A
A
019021
I am very sure that the SRQ Code is sent after command "T" as i can see the same in Prober Data log generated.
Any guidance would be helpful