Emerson XM678D Manual page 10

LABEL VALUE
404
FtY Kind of gas.
y
Atu Minimum STABLE superheat search
AMS y
Self self adaptive SH regulation enabling
SSH
8.0 Superheat set point.
Pb 8,0
Proportional band.
rS 0.0 Proportional band reset
inC 200
Integration time for superheat regulation.
Valve opening in case of error on probes
PEO 50
P5 or P6.
Start opening percentage for the time SFd.
OPE 85
It's not limited by the MnF parameter
Duration of soft start phase with opening at
SFd 0.1
OPE.
Valve opening percentage during hot gas
OPd 85 defrost. It's not limited by the MnF
parameter.
Maximum percentage of opening admitted
MnF 100
(during normal functioning).
Fot nU
Manual opening.
PA4 -0.5 Probe value at 4mA or at 0V.
P20 11.0 Probe value at 20mA or at 5V.
Lower
LPL -0.5
regulation.
Maximum operating pressure threshold
MOP 11.0
and valve closing of dML value.
Minimum operating pressure threshold
LOP -0.5
and valve opening of dML value.
dML 30 Delta [MOP - LOP].
MSH 60.0
Maximum superheat alarm threshold.
1592023140 XM678D GB r2.8 01.09.2017.docx
DESCRIPTION
Pressure Limit for superheat
RANGE
Type of gas used by plant.
Fundamental parameter for correct functioning of all system.
LABEL REFRIGERANT
R22
r22
134 r134A
290 r290 – Propane
404 r404A
47A r407A
47C
r407C
47F r407F
410 r410A
448 r448A
449
r449A
450
r450A
507 r507
513 r513A
CO2
r744 - Co2
No; yES
No; yES
[0.1°C to 25.5°C]
[1°F to 45°F]
[0.1°C to 60.0°C]
[1°F to 108°F]
[-12.0°C to 12.0°C]
0 to 255s
0 to 100%
0 to 100%
0.0 to 42min00sec (252)
0 to 100%
0 to 100%
0 to 100%
nU
Meas
Range
Unit
[PrU=rE] -1.0 to P20
BAR
[PrU=Ab] 0.0 to P20
[PrU=rE] -14 to P20
PSI
[PrU=Ab] 0 to P20
[PrU=rE] -10 to P20
dKP
[PrU=Ab] 0 to P20
Meas
Range
Unit
[PrU=rE] PA4 to 60.0
BAR
[PrU=Ab] PA4 to 60.0
[PrU=rE] PA4 to 870
PSI
[PrU=Ab] PA4 to 870
[PrU=rE] PA4 to 600
dKP
[PrU=Ab] PA4 to 600
PA4 to P20
LOP to P20
PA4 to MOP
0 to 100%
[LSH to 80.0°C]
[LSH to 144°F]
XM678D
NOTES
OPERATING RANGE
-50-60°C/-58÷120°F
-50-60°C/-58÷120°F
-50-60°C/-58÷120°F
-70-60°C/-94÷120°F
-50-60°C/-58÷120°F
-50-60°C/-58÷120°F
-50-60°C/-58÷120°F
-50-60°C/-58÷120°F
-45-60°C/-69÷120°F
-45-60°C/-69÷120°F
-45-60°C/-69÷120°F
-70-60°C/-94÷120°F
-45-60°C/-69÷120°F
-50-60°C/-58÷120°F
This parameter enables the search of the minimum stable
superheat. The lowest admitted value is LSH+2°C
This parameter enables the self adaptive regulation of the
superheat. CrE = no must to be set, when this function is enabled.
This is the value used to regulate superheat.
The valve changes its opening on the band [SSH, SSH + Pb]. At
SSH value of superheat the valve will be at 0% (without integral
contribution) and at [SSH + Pb] value of superheat the valve will
be at MnF. For values bigger than [SSH + Pb] the valve is
completely opened.
It allows to move the regulation band, above or below the SH set
point.
-
If a temporary probe error occurs, valve opening percentage is PEo
until PEd time is elapsed.
Opening valve percentage when start function is active. This phase
duration is SFd time.
Set start function duration and post-defrost duration. During this
phase the alarms are neglected.
Format: min.10sec, resolution: 10sec.
Opening valve percentage during hot gas defrost. During hot gs
defrost there is not SH control.
During regulation it sets the maximum valve opening percentage.
This value is not used during the SFd phase (soft start) and
during hot gas defrost, where the fixed percentace of the valve
opening is set by oPd.
It permits to force the valve opening to the specified value. This
value overwrites the one calculated by PID algorithm.
!!!! WARNING !!!!
It must be [Fot = nU] to have correct superheat regulation.
Value of pressure at 4mA for current probe [4 to 20mA] or value at
0V for ratiometric probes. The value is absolute or relative
according to PrU parameter.
Value of pressure at 20mA for current probe [4 to 20mA] or value
at 5V for ratiometric probes. The value is absolute or relative
according to PrU parameter.
EXPERT: when suction pressure goes down the lower bound LPL,
superheat regulation will use a fixed pressure value. Otherwise, the
normal pressure value will be used (according to PrU parameter).
If suction pressure exceeds maximum operating pressure value,
the instrument will signal this situation giving the MOP alarm
(according to PrU parameter).
If suction pressure exceeds minimum operating pressure value, the
instrument will signal this situation giving the LOP alarm (according
to PrU parameter).
Until MOP alarm is active, the valve will close, every second, of a
value equal to the dML percentage.
Until LOP alarm is active, the valve will open, every second, of a
value equal to the dML percentage.
If superheat value exceeds MSH value, the display will show the
MSH message until delay time SHd will expire.
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