Rockwell Automation 1769-IF4XOF2 Compact 8-Bit Low Resolution Analog I/O Combination Module - Manual (Page 62)

Publication 1769-UM008A-EN-P - November 2001
5-2 Module Diagnostics and Troubleshooting
Stand Clear of the Machine
When troubleshooting any system problem, have all personnel remain
clear of the machine. The problem could be intermittent, and sudden
unexpected machine motion could occur. Have someone ready to
operate an emergency stop switch in case it becomes necessary to
shut off power to the machine.
Program Alteration
There are several possible causes of alteration to the user program,
including extreme environmental conditions, Electromagnetic
Interference (EMI), improper grounding, improper wiring
connections, and unauthorized tampering. If you suspect a program
has been altered, check it against a previously saved program on an
EEPROM or UVPROM memory module.
Safety Circuits
Circuits installed on the machine for safety reasons, like over-travel
limit switches, stop push buttons, and interlocks, should always be
hard-wired to the master control relay. These devices must be wired
in series so that when any one device opens, the master control relay
is de-energized, thereby removing power to the machine. Never alter
these circuits to defeat their function. Serious injury or machine
damage could result.
Module Operation vs.
Channel Operation The module performs operations at two levels:
•
module level
•
channel level
Module-level operations include functions such as power-up,
configuration, and communication with a bus master, such as a
MicroLogix 1500 or Compact Logix controller.
Channel-level operations describe channel related functions, such as
data conversion and over-range detection.