Rockwell Automation 1769-HSC Compact High Speed Counter Module - Manual (Page 110)

110 Rockwell Automation Publication 1769-UM006E-EN-P - July 2013
Chapter 5 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.