Emerson XM678D - Quick Reference for Self Adaptive Regulation

1592023140 XM678D GB r2.8 01.09.2017.docx XM678D 10/15
LABEL VALUE DESCRIPTION RANGE NOTES
FtY
404
Kind of gas.
Type of gas used by plant.
Fundamental parameter for correct functioning of all system.
LABEL
REFRIGERANT
OPERATING RANGE
R22
r22 -50-60°C/-58÷120°F
134
r134A -50-60°C/-58÷120°F
290
r290 – Propane -50-60°C/-58÷120°F
404
r404A -70-60°C/-94÷120°F
47A
r407A -50-60°C/-58÷120°F
47C
r407C -50-60°C/-58÷120°F
47F
r407F -50-60°C/-58÷120°F
410
r410A -50-60°C/-58÷120°F
448
r448A -45-60°C/-69÷120°F
449
r449A -45-60°C/-69÷120°F
450
r450A -45-60°C/-69÷120°F
507
r507 -70-60°C/-94÷120°F
513
r513A -45-60°C/-69÷120°F
CO2
r744 - Co2 -50-60°C/-58÷120°F
Atu
y
Minimum STABLE superheat search No; yES
This parameter enables the search of the minimum stable
superheat. The lowest admitted value is LSH+2°C
AMS
y
Self self adaptive SH regulation enabling No; yES
This parameter enables the self adaptive regulation of the
superheat. CrE = no must to be set, when this function is enabled.
SSH
8.0
Superheat set point.
[0.1°C to 25.5°C]
[1°F to 45°F]
This is the value used to regulate superheat.
Pb
8,0
Proportional band.
[0.1°C to 60.0°C]
[1°F to 108°F]
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.
rS
0.0
Proportional band reset [-12.0°C to 12.0°C]
It allows to move the regulation band, above or below the SH set
point.
inC
200
Integration time for superheat regulation. 0 to 255s -
PEO
50
Valve opening in case of error on probes
P5 or P6.
0 to 100%
If a temporary probe error occurs, valve opening percentage is
PEo
until PEd time is elapsed.
OPE
85
Start opening percentage for the time
SFd
.
It’s not limited by the MnF parameter
0 to 100%
Opening valve percentage when start function is active. This phase
duration is SFd time.
SFd
0.1
Duration of soft start phase with opening at
OPE.
0.0 to 42min00sec (252)
Set start function duration and post
-
defrost duration.
During this
phase the alarms are neglected.
Format: min.10sec, resolution: 10sec.
OPd
85
Valve opening percentage during hot gas
defrost. It’s not limited by the MnF
parameter.
0 to 100%
Opening valve percentage during hot gas defrost. During hot gs
defrost there is not SH control.
MnF
100
Maximum percentage of opening admitted
(during normal functioning).
0 to 100%
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.
Fot
nU
Manual opening.
0 to 100%
nU
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.
PA4
-0.5
Probe value at 4mA or at 0V.
Meas
Unit
Range
BAR
[PrU=rE] -1.0 to P20
[PrU=Ab] 0.0 to P20
PSI
[PrU=rE] -14 to P20
[PrU=Ab] 0 to P20
dKP
[PrU=rE] -10 to P20
[PrU=Ab] 0 to P20
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.
P20
11.0
Probe value at 20mA or at 5V.
Meas
Unit
Range
BAR
[PrU=rE] PA4 to 60.0
[PrU=Ab] PA4 to 60.0
PSI
[PrU=rE] PA4 to 870
[PrU=Ab] PA4 to 870
dKP
[PrU=rE] PA4 to 600
[PrU=Ab] PA4 to 600
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.
LPL
-0.5
Lower Pressure Limit for superheat
regulation.
PA4 to P20
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).
MOP
11.0
Maximum operating pressure threshold
and valve closing of dML value.
LOP to P20
If suction pressure exceeds maximum operating pressure value,
the instrument will signal this situation giving the MOP alarm
(according to PrU parameter).
LOP
-0.5
Minimum operating pressure threshold
and valve opening of dML value.
PA4 to MOP
If suction pressure exceeds minimum operating pressure value, the
instrument will signal this situation giving the LOP alarm (according
to PrU parameter).
dML
30
Delta [MOP - LOP].
0 to 100%
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.
MSH
60.0
Maximum superheat alarm threshold.
[LSH to 80.0°C]
[LSH to 144°F]
If superheat value exceeds
MSH
value, the display will show the
MSH message until delay time SHd will expire.