A52x Series Electronic Refrigeration Controller with Adaptive Defrost Technical Bulletin
14
Universal Inputs and Alarms
Universal Input Modes
You can set each of the universal inputs to one of the modes in Table 5. When you select an input mode, one or
more control actions become associated with that mode.
Note:
The system defines alarm actions separately from control actions. The selection of a particular input mode
may affect the list of available alarms. For example, Door Open Too Long becomes a potential alarm only
after you define the input as Door Open.
Setting Up Universal Input Modes
You can set each of the two universal inputs to one of these modes. When you configure an input mode, you must
specify if the input is a binary or an analog input. You then indicate what level of input equates to the TRUE
condition.
Table 5: A52x Universal Input Modes and Control Actions
Mode
Control Action when condition is TRUE
None
The state of the universal input has no effect on the A52x control.
Refrigerant Leak
System Shutdown. The system remains shut down as long as the Refrigerant Leak condition
persists. A system shutdown takes priority over the normal control of the compressor, defrost,
and fan relays.
Man In Room
You can select one of the following options for this input mode:
• Normal Control indicates that relays R1-R4 are unaffected.
• System Shutdown. This option takes priority over the normal control of the compressor,
defrost, and fan relays.
• Low Speed Fan, if running at High Speed. This option becomes available only if the
control is configured with the two-speed fan option. This takes priority over the normal
control of the fan relays. This option is available on the A525 Controller only.
• Energize Auxiliary Relay. This option becomes available only if the two-speed fan option
is not used. This option is available on the A525 Controller only.
Door Open
You can select one of these options for this binary input mode:
• Normal Control indicates that R1-R4 are unaffected.
• Low Speed Fan. This option becomes available only if the control is configured with the
two speed fan option. This option takes priority over the normal control of the fan relays.
This option is available on the A525 Controller only.
• Shut
off
cooling.
• Energize Auxiliary Relay if the two speed fan option is not used. This option is available
on the A525 Controller only.
Emergency Switch
(Wall switch)
The system shuts down when it detects an input change from False to True. The system
remains shut down until the switch clears. A system shutdown takes priority over the normal
control of the compressor, defrost, and fan relays.
Table 6: A52x Universal Inputs and Mode Selections
Universal Input
Mode Selection
Binary or Analog
True State (binary)
True State (analog)
1
None, not used
Refrigerant Leak
Man in Room
Door Open
Emergency Switch
BIN / ANA
OPEN / CLOSED
> nnn (user enters voltage)
2
BIN / ANA
OPEN / CLOSED
> nnn (user enters voltage)
