Emerson iPro, Installation And Operation Manual

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Refrigeration Control Modes Software Overview • 31
10.3.5.5. Wait Mode
When the case controllers are connected in a lineup together and one lead case is the master, the case controllers utilize Wait mode.

If there is no master slave network configured, Wait mode is skipped. During Wait mode there is no refrigeration or defrost occurring -
the system is idle for just a moment before entering refrigeration again. The operation of the fan is outlined by the fan parameter
FanOp . In the refrigeration lineup, the master controller has control of certain system critical valves: the EEPR and liquid line solenoid
valve. Therefore, when the entire lineup is in defrost, the slave case could possibly terminate defrost before the master case and attempt
to enter refrigeration again. Because the slave cases cannot enter refrigeration without the master opening the EEPR and LLSV for the
entire circuit, the slave must wait on the master to finish defrost before it can enter refrigeration again. The opposite situation also exists
where the master case can terminate defrost before any of the slaves and enter refrigeration again before the slave controller defrost
completes. In this situation, the master case enters refrigeration again while the slave cases are still in defrost, which results in
refrigeration and defrost at the same time on the slave cases since the master controls the liquid feed for the entire circuit. In order to
avoid these critical problems and synchronize defrost, the case controller utilizes a Wait mode after termination of defrost. After
termination of defrost and Drip mode then the controller enters Wait mode. Once in Wait mode, refrigeration will start again once the
master controller of the lineup signals
start refrigeration . During the defrost cycle, the master controller is monitoring the Wait mode
status of each of the cases in the lineup, and once all cases enter Wait mode, refrigeration is immediately started again for all cases.
10.3.5.6. Synchronization of Defrost Schedules
When a master/slave lineup is present, the defrost schedule of all the slave case controllers is locked from editing. Any desired changes
to the defrost start time or number of defrosts per day must be made on the master controller and will then be automatically synced to
all of the online slave case controllers. If a slave case controller happens to be offline when a defrost change is made, the change will be
written to the offline slave controller once it returns online.
10.3.5.7. Defrost Heater Current Monitoring
The case controller has the ability to monitor the defrost heater RMS current of each case through the use of an external current
transducer. The current transducer should be placed on the defrost circuit for the entire case. The current transducer is
Emerson

P/N 251-7000 and is a 0-5VDC signal, split core sensor with a selectable range of 30, 60, and 120 amps. The case controller will
monitor the defrost heater amperage once the relay call for the defrost heater is ON. Once the amperage sensed by the defrost heater

CT is above a threshold for a time delay, the defrost heater status is considered ON. If the defrost heater relay call and defrost heater
status are not equal, a
command failure alarm is automatically sent to the E2E and the E2E will generate an alarm log entry.

If you do not wish to use the defrost heater current monitoring, do not set up any analog inputs for defr amps .
Parameters:
10.3.5.8. Defrost Heater Lockout
When connected with the E2E controller, a network of case controllers’ defrost cycles can be managed by the E2E to ensure a
maximum number of defrost circuits are active at any given time. To use this feature of E2E and the case controller, all case controllers
must be connected and online with E2E via BACnet MS/TP. The E2E controller will need to have the Defrost Inhibitor application
loaded and configured. Once the Defrost Inhibitor application is loaded and configured and all case controllers are online, the E2E can
place a lockout on the case controller defrost heater relay if the maximum number of circuits in defrost has been exceeded. If the case
controller defrost heater relay is locked out during defrost, a small lock icon will be displayed with the defrost icon as shown below in
Figure 10-1 :
Parameter Description Range
defrAmpOn Amps required from the CT for defrost heater to be

considered ON
0-60 Amps
defrAmpDel Time delay for defrost heater status to change to ON
once the threshold is reached.
1-90 Seconds
Table 10-7 - Defrost Amp Parameter List