JOHNSON CONTROLS
94
FORM 160.84-OM1
ISSUE DATE: 9/21/2017
SECTION 3 - OPTIVIEW™ CONTROL CENTER FUNCTIONS AND NAVIGATION
MESSAGE DESCRIPTION
EXPANSION I/O – SERIAL
COMMUNICATIONS
Valid communication between the microboard and the LTC I/O Board have been
disrupted for 3 consecutive attempts. The chiller will automatically restart when valid
communication is received.
ISOLATION VALVES - NOT
CLOSED
The optional brine freeze protection motorized isolation valves Close output is energized
> 40 seconds but the feedback from the valve limit switch does not indicate it closed for
3 continuous seconds. This cycling fault is released when the isolation valves closed
input is energized.
LEAVING CHILLED LIQUID –
LOW TEMPERATURE
The Leaving Chilled Liquid Temperature has decreased to the programmed Shutdown
Temperature Setpoint. If the chiller is running when this occurs, a Soft Shutdown is
performed. The chiller will automatically restart when the temperature increases to the
programmed Restart Temperature Setpoint.
MBC – FAULT
CONTACTS OPEN
Refer to “MBC Shutdown – Requesting Fault Data” message above. If the control cen-
ter’s microboard does not receive the cause of the MBC fault over the serial link within
10 seconds after the fault contacts open is recognized, it is assumed it is not forthcom-
ing and that message is replaced with this message.
MBC - LOW INPUT VOLTAGE Main DC supply voltage to the MBC decreased below 135VDC (150-10%)
MBC – SERIAL
COMMUNICATIONS
This Cycling Shutdown is set when an invalid or no response is received from the MBC
to a Modbus command from the panel for 3 consecutive attempts with a 2 second
timeout between attempts. It shall be triggered by the Modbus communications task
when its fault conditions are met (thresholds of consecutive timeouts, ID mismatches,
checksum failures, or error packets). It is released when a valid response is received.
MBC SHUTDOWN –
REQUESTING FAULT DATA
The MBC has shutdown the chiller and the control center has not yet received the cause
of the fault from the MBC via the serial communications link. The MBC shuts down the
chiller by opening the MBC Fault contacts (located on the MBC control board and con-
nected to TB3-70 in the control center). The microboard in the control center then sends a
request for the cause of the fault to the MBC control board over the serial link. Since serial
communications are initiated every 2 seconds, this message is typically displayed for a
few seconds and then replaced with one of the other MBC fault messages in this section.
MBC – SPEED SIGNAL FAULT
This Cycling Shutdown is set when the MBC looses the speed signal that is expected
from the VSD or speed signal is less than 10 Hz. While the MBC is commanded in Rota-
tion Mode. The MBC Fault contacts open. The MBC remains in Levitation mode with the
motor shaft levitated until commanded to de-levitate over serial comms. This shutdown
is released when the MBC is out of Rotation mode or speed greater than 10 Hz is trans-
mitted. A 10 second bypass exists when the initial command to Rotation Mode occurs.
MBC – STARTUP FAILURE
This Shutdown is set when the chiller fails to exit the MBC startup state within 60
seconds, during a chiller start. Refer to the Basic Operation section of this manual for
conditions necessary to complete MBC startup successfully. Check fault history details
to determine which specic conditions were not met.
MBC – V13 LOW FREQUENCY
DISPLACEMENT
The MBC has measured shaft displacement is greater than 90 µm from center in the
orthogonal radial axis designated V at the impeller end radial magnetic bearing during
Levitation or Rotation mode over a 7 second window (approximately 2/3 of the air gap
space to the touchdown bearing). The MBC Fault contacts open. The MBC remains in
Levitation mode with the motor shaft levitated until commanded to de-levitate over serial
comms. This shutdown is released when displacement is less than 90 µm.
MBC - UNKNOWN PARAMETER
FILE
This Cycling shutdown is set when the bearing setup parameter le received from Opti-
View is not an expected le format. The fault is released when the error is corrected.
This fault could be corrupted data transfer between OptiView and the MBC.
MBC – V13 POSITION
The MBC has measured shaft displacement is greater than 100 µm from center in the
orthogonal radial axis designated V at the impeller end radial magnetic bearing during
Levitation or Rotation mode (approximately 2/3 of the air gap space to the touchdown
bearing). The MBC Fault contacts open. The MBC remains in Levitation mode with the
motor shaft levitated until commanded to de-levitate over serial comms. This shutdown
is released when displacement is less than 100 µm.
TABLE 11 - CYCLING SHUTDOWN MESSAGES (CONT'D)
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