Rockwell Automation 1746-NO8V SLC 500 8-Point Analog Output Module/ User Manual User Manual
Page 60
Publication 1746-UM026A-EN-P - September 2003
7-2 Maintenance and Safety
The following section describes several safety areas you should be
aware of when troubleshooting your SLC 500 system.
Indicator Lights — When the module status LED on the module is
illuminated, the module is receiving power.
Activating Devices When Troubleshooting — When
troubleshooting, never reach into the machine to actuate a device.
Unexpected machine motion could occur. Use a wooden stick.
Stand Clear of Machinery — When troubleshooting any SLC 500
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.
When troubleshooting, pay careful attention to this general warning:
Program Alteration — There are several 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 the
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.
WARNING
!
POSSIBLE EQUIPMENT OPERATION
Never reach into a machine to actuate a switch since
unexpected machine motion can occur and cause
injury.
Remove all electrical power at the main power
disconnect switches before checking electrical
connections or inputs/outputs causing machine
motion.
Failure to observe these precautions can cause
personal injury or equipment damage.