JOHNSON CONTROLS
241
SECTION 8 - MICROPANEL
FORM 201.23-NM2
ISSUE DATE: 3/9/2015
8
Any faults that occur after the initial fault, which occur
within the comms transmission time frame following
the inception of the first fault, will be stored and trans-
mitted to the Micro Logic Board together with the first
fault data. These faults will appear in the "All Fault"
display in the History.
A snapshot of the operating parameters of the VSD is
continuously updated in battery-backed memory once
every program loop. Upon receipt of a first fault, the
snapshot of the operating parameters will be stored in
memory and are transmitted to the panel as the fault
data.
Fault Relay/Fault Acknowledge Bit
Control of the Fault Relay is from the VSD Logic
Board. The Fault Relay on the VSD will be closed dur-
ing a non-fault condition.
When a running or pre-charge fault occurs on the VSD,
the fault relay will immediately open. The relay will
not open for non-running faults that occur.
When the Chiller Control Board sees the VSD fault re-
lay open, it will immediately take a snapshot of system
data and save it to the history buffer.
A fault acknowledge bit from the Chiller Control
Board is sent to the VSD via comms after receiving
valid fault data from the VSD. When the VSD Logic
Board receives the fault acknowledge via comms from
the panel it will reset (close) the Fault Relay. The fault
acknowledge is reset by the Chiller Control Board after
the Fault Relay is closed by the VSD Logic Board.
VSD Fault Compressor Start Inhibit
If a VSD fault condition exists while the compressor is
not running or pre-charging, the Chiller Control Board
will not try to start the faulted compressor(s). The start
inhibit will be automatically cleared when the fault
condition goes away.
UNIT WARNINGS
Unit Warning Operation
Unit warnings are caused when a condition is pres-
ent requiring operator intervention to restart the unit.
All setpoints, program values, and options should be
checked before operating the unit. Warnings are not
logged to the history buffer. If a unit warning is in
effect, the message will be displayed to the operator
when the STATUS key is pressed.
LD10605
STATUS
KEY
Low Battery Warning
The LOW BATTERY WARNING can only occur at
unit power-up. On micropanel power-up, the RTC bat-
tery is checked to see if it is still operational. If it is,
normal unit operation is allowed. If the battery voltage
is determined to be low, the following warning mes-
sage is displayed indefinitely.
UNIT WARNING: !! LOW BATTERY !!
CHECK SETPOINTS/PROGRAM/OPTIONS/TIME
If a low battery condition exists, all programmed
setpoints, program values, time, schedule, and history
buffers will have been lost. These values will all be re-
set to their default values, which may not be the desired
operating values. Once a bad battery is detected, the
unit will be prevented from running until the MANU-
AL OVERRIDE key is pressed. Once the MANUAL
OVERRIDE key is pressed, the anti recycle timers will
be set to the programmed default anti recycle time to
allow the operator sufficient time to check setpoints,
program values, etc.
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