Watlow CLS200 - Manual (Page 190)

Chapter 9: Troubleshooting and Reconfiguring CLS200 Series User’s Guide
174 Watlow Anafaze Doc.# 0600-3050-2000
3. Restore power to the controller.
4. Go to the DIGITAL INPUTS parameter in the MANUAL
I/O TEST menu. This parameter shows whether the
digital inputs are H (high, or open) or L (low, or closed).
5. Attach a wire to the terminal of the digital input to
test. When the wire is connected only to the digital in-
put terminal, the DIGITAL INPUTS parameter should
show that the input is H (high). When you connect the
other end of the wire to controller common (TB50 ter-
minal 3), the DIGITAL INPUTS parameter should
show that the input is L (low).
Additional Troubleshooting for Computer
Supervised Systems
These four elements must work properly in a computer-su-
pervised system:
• The controller
• The computer and its EIA/TIA-232 or EIA/TIA-485 se-
rial interface
• The EIA/TIA-232 or EIA/TIA-485 communication lines
• The computer software
For troubleshooting, disconnect the communications line
from the computer and follow the troubleshooting steps in
the first section of this chapter. The next few sections ex-
plain troubleshooting for the other elements of computer
supervised systems.
Computer Problems
If you are having computer or serial interface problems,
check the following:
• Check your software manual and make sure your com-
puter meets the software and system requirements.
• Check the communications interface, cables, and con-
nections. Make sure the serial interface is set accord-
ing to the manufacturer’s instructions.
• To test an EIA/TIA-232 interface, purchase an EIA/
TIA-232 tester with LED indicators. Attach the tester
between the controller and the computer. When the
computer sends data to the controller, the tester’s TX
LED should blink. When the computer receives data
from the controller, the RX LED should blink.
• You can also connect an oscilloscope to the transmit or
receive line to see whether data is being sent or re-
ceived. If the serial port does not appear to be working,
the software setup may need to be modified or the
hardware may need to be repaired or replaced.