© Danfoss A/S (AC-MCI / sw), 2014-11
DKRCC.PS.RQ0.B7.02 /520H8832
11
Manual
Superheat Controller EIM 336
Related parameters:
Symbolic name
PNU
Description
--- Def Activate
50011 Defrost activating, 0 = no defrost, 1 = defrost active
--- Def Hold OD
50008 Opening degree during Def Hold Ti 1
--- Def HoldTi 1
50009 Defrost hold time 1
--- Def HoldTi 2
50010 Defrost hold time 2
--- DefHold shdw
64305 Copy of 50008. If it is required to write Def Hold OD frequently, this should be used instead.
Defrosting
A defrost sequence is initiated by setting the defrost activate
register “Def Activate” to 1. As long as this register is kept at 1, the
valve opening degree is 100%. When “Def Activate” returns to 0,
the valve opening degree is kept at “Def Hold OD” for “Def Hold Ti
1” seconds. When this time expires, the valve opening degree is set
to a calculated average opening degree for “Def Hold Ti 2” seconds.
When this time expires the controller resumes normal operation.
Note:
That defrost is not initiated by the EIM 336, but must be initiated
by the master controller. In a standalone configuration the defrost
mode is not possible.
If a more dynamic control of the opening degree during defrost is
required, the user should disable the “Def Hold Ti 2” by setting it
to 0, and only use the “Def Hold Ti 1”. If frequent changes are to be
made to the “Def Hold OD”, the parameter “DefHold shdw” should
be used instead. This parameter is an exact copy of the “Def Hold
OD” except that it is not placed in the Eeprom.
Related parameters:
Symbolic name
PNU
Description
--- LOC Trig
50003 Trigger value for loss of charge
--- LOC Reset
50004 Reset value for loss of charge
--- LOC Timer
50005 Timer to trigger LOC alarm
--- LOC Alarm
50006 Loss of charge alarm flag, 0 = no alarm, 1 = LOC alarm
--- LOC SH Trig
50007 SH error trigger level for LOC alarm
--- LOC Tmr
3102
Loss Of Charge time readout displays the elapsed time since the alarm became active.
LOC detection
When a system loses refrigerant charge the controller will have
difficulties keeping the superheat low, even when increasing the
valve opening degree. Therefore, if both the valve opening degree
and the superheat are high for a long period of time, this could
indicate that refrigerant charge was lost.
When the valve opening degree exceeds the trigger level "LOC
Trig, and the superheat exceeds the superheat trigger level "LOC
SH Trig", a timer is started.
When the timer exceeds the user defined time “LOC Timer” the
“LOC Alarm” is set. If the valve opening degree drops below the
user defined reset level “LOC Reset”, the timer and the alarm are
reset.
The loss of charge alarm does not perform any actions, except
setting the “LOC Alarm”.
Related parameters:
Symbolic name
PNU
Description
--- Reset alarm
2046
1 = Clear alarm
--- EKC Error
20001 Common error flag. EKC Error is SET if any other Error Alarm is ON.
--- S2 Error
20002 S2 sensor error. If the sensor error occurs, the valve OD will be set to 80% of the Avg. opening (PNU 50021) - see
troubleshooting.
--- Pe inp.error
20005 Pressure transmitter out of range. If the sensor error occurs, the valve OD will be set to 80% of the Avg. opening (PNU
50021) - see troubleshooting
--- No Rfg. Sel.
20006 Refrigerant not selected
--- LOC Alarm
50006 Loss of charge alarm. No action will be performed except setting the alarm.
--- Ctrl Status
3100
Bit mappped status register, see also appendix 2
Alarms and clearing alarms
Several alarms are registered and made available on modbus. Most
of these are automatically cleared when the error is no longer
present.