Emerson EC2-552 - Suction Superheat Monitoring

OI_EC2-XC645CX_A1_A2L_A3_EN_Rev01_866933.docx EC2-XC645CX 41/54
19.3 Suction superheat monitoring
Controller can monitor the suction superheat, and signal situations of low superheat, with a pre-
alarm and alarm thresholds.
According to the settings, compressors can be stopped in case of low superheat alarm, to
preserve compressor integrity.
Suction Superheat detecting
To detect the suction superheat an
auxiliary probe among P3 (term. 3 - 4)
or P4 (term. 27 - 28) has to be set as
superheat temperature probe.
To do this set ASH9 = P3 or P4.
Controller automatically calculates the
suction superheat using the value of
the suction probe P1 and the probe set
in the parameter ASH9.
The SH is available after 1 minute
since at least one compressor is
running.
Low superheat signalling and actions
Controller can signal low superheat pre-alarm, only warning, and low superheat alarm, warning
and regulation according to parameter ASH4.
The alarm messages and the regulation are described in the following table.
CODE MEANING CAUSE ACTION RESET
PrSH
Low
superheat
Pre-alarm
The superheat is less
than:
SH< ASH2 + ASH0
for ASH1 time
Only warning
Automatic:
when superheat:
SH>ASH0+ASH2+1°C(2°F)
ALSH
Low
superheat
alarm
The superheat is less
than: SH< ASH2 for
ASH3 time
Regulation depends
on ASH4:
ASH4 = no: regulation
not affected.
ASH4 = yes:
regulation is stopped.
Automatic:
when superheat:
SH> ASH5 + ASH2