Replacing Boards - Allen-Bradley 1779-KFMR User Manual

Chapter 5
Operation and Troubleshooting

Replacing Boards

5 6
transmitting HDLC flag sequences which are indicated by the
TRANSMIT indicator turning on half-intensity yellow.
Whenever you want to turn off interface power or switch out of RUN
mode, press the EXIT REQUEST switch first. This exit request saves the
other nodes time they would otherwise waste trying to pass the token to a
node that they can't find.
If you determine through the troubleshooting procedure in the next section
that one of the interface boards has faulted, replace it with a spare.
Electrostatic discharge can damage integrated circuits or other
semiconductors in these boards if you touch connectors or pins. Avoid
electrostatic damage by observing the following precautions:
Touch a grounded object to discharge yourself before handling the
boards.
Do not touch the pins for connection to ribbon cables.
When not in use, keep each space board in its static-shielded bag.
CAUTION: Electrostatic discharge can degrade performance
or cause permanent damage to the boards. Handle as stated
above.
To replace one of the boards with a spare, follow these steps:
1. Press the EXIT REQUEST switch.
2. When the EXIT COMPLETE indicator goes on, turn off the AC
POWER switch.
3. Disconnect the AC power at the source (disconnect switch or circuit
breaker).
WARNING: Always disconnect AC power at the source before
attempting to remove connections at the interface power
terminals. If you fail to heed this warning, you will receive an
electrical shock from touching the terminals.