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OPERATING PROCEDURES
PLANT LOOP TO COMPUTER TRANSFER MODULE LEDs AND CONTROLS
4 - 2
I-E96-621A
®
Status LED
The Status LED is a red/green LED that displays the operating
status of the PCT. It has three possible states. Table
lists
the meaning of the status LED states. Refer to
for
corrective action if the status LED indicates that an operating
error exists.
CPU LEDs
During normal operation, the CPU LEDs keep a count of the
commands and replies that pass through the PCT. If a commu-
nication error occurs, these LEDs display an error code and
the Status LED turns RED. Refer to Table
for a list of CPU
LED error codes and corrective action.
Memory LEDs
There are two Memory LEDs. The MEM LED 2 is on while the
module is correcting single bit errors. Both LEDs are on when a
two-bit error or a complete memory failure occurs.
Stop Pushbutton
Push the stop pushbutton and wait for the status LED to turn
red before removing a PCT from the Module Mounting Unit.
Using the stop pushbutton allows any NVM write in progress to
complete before the module halts operation.
Reset Pushbutton
Pressing the reset pushbutton causes:
1. Restoration of PCT to power-up values after a halt.
2. Recovery from an operator-initiated stop or a module
time-out.
Table 4-1. PCT Status LED States
LED State
Meaning
Off
No power to the PCT.
Solid Green
The PCT is in the EXECUTE Mode.
Solid Red
The PCT diagnostics detect a hardware failure or
configuration problem. CPU LEDs display an error
code when the status LED is red.