York OPTIVIEW - MBC Cycling Shutdowns

JOHNSON CONTROLS
119
SECTION 2 - OPTIVIEW CONTROL CENTER INTRODUCTION
FORM 160.78-O2
ISSUE DATE: 5/22/2017
2
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.
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 – HIGH AMPLIFIER
TEMPERATURE
This Cycling Shutdown is set when the MBC amplier temperature exceeds 140ºF
(60 ºC). This condition is determined by the Optiview control software from temperature
data transmitted through the serial comms. The shutdown is released when amplier
temperature drops 18ºF (10 ºC) below the trip value.
MBC – HIGH DC/DC
TEMPERATURE
This Cycling Shutdown is set when the MBC DC/DC Converter board temperature ex-
ceeds 167ºF (75 ºC). This condition is determined by the Optiview control software from
temperature data transmitted through the serial comms. The shutdown is released when
DC/DC converter temperature drops 18ºF (10 ºC) below the trip value.
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 8 successive requests. It shall be triggered by
the Modbus communications task when its fault conditions are met (thresholds of con-
secutive timeouts, ID mismatches, checksum failures, or error packets). It is released
when a valid response is received. This fault becomes active during the Stopped State
or the MBC Startup State when the MBC intializes (VSD DC Bus Voltage has increased
enough power the MBC). It stays active during Run and Soft Shutdown, and becomes
inactive at coastdown or stop when the DC Bus Voltage is less than 100V.
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 Emergency Shutdown (ESD) contacts (located on the MBC
control board and connected between TB6-15 and TB6-53 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 while the MBC is commanded in Rotation Mode. The MBC ESD Fault
contacts open. The MBC remains in Levitation mode with the motor shaft levitated until
commanded to de-levitate over serial comms or VSD DC buss power depletes. This
shutdown is released when the transmission is reestablished. A 10 second bypass ex-
ists 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 sec-
onds, during a chiller start. Refer to YORK YMC
2
Service Manual (Form 160.78-M2) for
conditions necessary to complete MBC startup successfully. Check fault history details
to determine which specic conditions were not met.
MBC – STOP (FAULT)
CONTACTS OPEN
Refer to “MBC Shutdown – Requesting Fault Data” message above. If the control
center’s microboard does not receive the cause of the MBC ESD fault over the serial
link within 10 seconds after the ESD contacts open is recognized, it is assumed it is not
forthcoming and that message is replaced with this message.
MBC – V13 LOW FREQUENCY
DISPLACEMENT
The MBC has measured shaft displacement is greater than 75 µm from center in the
orthogonal radial axis designated V at the impeller end radial magnetic bearing dur-
ing Levitation or Rotation mode over a 7 second window (approximately 1/3 of the air
gap space to the touchdown bearing). The MBC ESD Fault contacts open. The MBC
remains in Levitation mode with the motor shaft levitated until commanded to de-levitate
over serial comms or VSD DC buss power depletes. This warning is released when
displacement is less than 75 µm.
TABLE 8 - CYCLING SHUTDOWN MESSAGES (CONT'D)