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SIMULTANEOUS FILLING
Where two or more refrigerators are connected to the same Liquid Nitrogen supply, economies in the use of
Nitrogen may be realised by synchronising the filling of refrigerators. This reduces the number of fill cycles
required and hence the losses due to nitrogen being trapped in the common supply pipework and vented at the
end of a fill cycle.
To use this feature connect the EXT FILL terminals of the refrigerators using 2 core cable, ensuring that + is
connected to + and - to-. (See Appendix G).
Whenever a refrigerator in the connected group starts to fill a signal is sent to all of the others. This causes
them to start a fill cycle if they are not already full.
Up to 20 refrigerators may be connected together in this way.
Make sure however that the supply pressure is adequate to complete filling in a responsible time. If not, a
supply alarm may be generated by one or more of the controllers. For large installations it may be better to
connect the refrigerators in two or more groups. The best groupings will depend upon pipework layout.
REMOTE ALARM CONNECTION
A changeover relay contact is provided to facilitate reporting of an alarm condition at a point remote from the
refrigerator.
In the ‘good’ condition the relay is energised. i.e. the Normally Open (NO) contact is closed and the Normally
Closed (NC) contact is open.
If the remote alarm is activated or there is a power failure the relay is released and the contact changes over.
For safety reasons the relay should switch no more than 2 Amps at 50V AC/DC. (Resistive load).
AUXILIARY RELAY
To cater for possible additional or special functions an auxiliary relay is provided. It is not used in this version of
the software.
24V AC OUTPUT
Up to 0.5 Amps may be drawn from this output. It may be used for example to power a lamp or siren from the
remote alarm contact.
A suitable rated fuse (0.5A max) should be inserted in F2 if this feature is required.
Do not exceed 0.5 Amps as this may overload the M269CE safety transformer.
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