User guide
Revision 7.1b Page 18 of 31
Mercury Coldroom Panel Installation Guide
www.resourcedm.com
Warning
Please Note
The specifications of the product detailed on this
Set-Up Guide may change without notice. RDM
Ltd. shall not be liable for errors or for incidental
or consequential damages, directly and indirectly,
in connection with the furnishing, performance or
misuse of this product or document.
Ensure that all power is
switched off before
installing or maintaining
this product
P-30
Broadcast ID
ID of Plant Controller being used to broadcast Suction Pressure
The Broadcast ID is derived from the Rotary Switch positions set on the Plant controller
which is providing the remote suction pressure.
Note: No two Plant controllers on a local area network can have the same rotary switches
positions set. This will have adverse affects on control.
P-31
Refrigerant
Type of refrigerant used in system. See: Refrigerant Table above
P-32
Pressure Units
Absolute or Gauge
P-33
Evap Offset
Offset to allow for pressure drop over distance
P-34
Glide
Allows the calculated temperature to be offset by subtracting the value at (P-34)
dFLt
Restore default values
Restores all of the parameters to their default values
Load Shedding
Used on CO2 sites for load shedding on CO2 Compressor Faults or CO2 Vessel High Pressure Alarms
Cases can be put into a “CO2 Case Off” mode which will open the LLV/EEV and stop the fans to reduce the load on the pack or to
reduce the CO2 vessel pressure
See: RDM CO2 load shedding user guide
EEV Control Using Pressure
There are several ways to use the suction pressure to calculate the evaporator in temperature
Mercury Switch (PR0018-PHI)
(P-17 set to Rem1) The Mercury Switch can be used for EEV control on an Island by island basis. A suction pressure transducer is
connected from the case Island to the 4-20mA input of the Mercury Switch and the pressure read from this transducer is converted to a
temperature based on the gas type being used by the system. This temperature is transmitted to each controller connected to the switch
and along with the suction temperature probe local to the controller, the superheat is calculated. Please note that RDM recommended
that the evaporator in temperature probe is fitted as the controller will use this to calculate the superheat in the event of a
communication loss with the Mercury Switch. P-17 allows for the use of this remote temperature provided by the Mercury Switch. Please
see the Mercury Switch user document (PR0018-PHI) for further details.
Remote pressure Direct from a Plant Pack Controller
(P-17 set to Rem1, Rem2 or Rem3 depending on which input the suction transducer is connected to on the plant controller, transducer
input 1, 2 or 3)
(P-30) set to ID of Plant Pack Controller (Rotary Switch Setting), (P-31) set to refrigerant type, (P-32) set to pressure units Absolute or
Gauge
Maximum Operating Pressure
Maximum Operating Pressure (MOP) support added to Coldroom software. In an EEV application the remote evaporator in value is
obtained from the Mercury switch on which the coldroom panel is connected. MOP is a remote command sent from the Mercury switch to
the coldroom panel to close the EEV valve when a predetermined pressure is reached. This MOP value is configured in the Mercury
switch setup. MOP is also used in the M software and although a remote evaporator temperature is not used the LLV can be closed
when the MOP value is reached.