Emerson XM678D - Page 11

1592023140 XM678D GB r2.8 01.09.2017.docx XM678D 11/15
LABEL VALUE DESCRIPTION RANGE NOTES
LSH
2.0
Minimum superheat alarm threshold.
[0.0°C to MSH]
[0°F to MSH]
If the superheat value is lower than
LSH
during the
SHd
delay time,
then the display will show the message LSH. As soon as the
superheat value is lower than LSH value, the valve will close
immediately, without waiting the SHd delay time (to avoid
evaporator flooding).
SHY
1.0
Hysteresis for superheat alarm recovery
[MSH – SHY] and [LSH + SHY].
[0.1°C to 25.5°C]
[1°F to 45°F]
-
SHd
3.0
Delay of superheat alarm signaling. 0.0 to 42min00sec (252)
If a superheat alarm occurs, the delay time
SHd
will have to expire
before the controller shows an alarm.
Format: min.10sec, resolution: 10sec.
FrC
0
Integration additive constant (Fast-
recovery).
0 to 100s
It permits to d
ecrease faster the integral action when
SH
value is
below the set-point.
With higher values the valve closes faster.
If [FrC = 0] fast recovery function is disabled.
Sub
10
Number of pressure values used to
calculate the average pressure
0÷100
It uses the last average values of the pressure to calculate the
superheat.
SLb
0.0
Reaction time 0÷255s
0 = controller calculates automatically the time to update the valve
position.
1÷255s = controller updates valve position every SLb seconds
tEP
nu
Predefined valve selection. nU to 10
See par. 6.3.
nU = manual setting.
tEU
bP
Kind of valve. uP; bP
uP
= unipolar valve (5
-
6 wires);
bP = bipolar valve (4 wires).
HSF
FUL
Kind of motor movement HAF; FUL
HAF
= half step. Use this setting for the unipolar valve.
FUL = half step. Use this setting for the bipolar valve.
LSt
0
Minimum number of steps where the valve
can be considered as completely closed.
0 to USt (* 10) For manual adjusting of the valve.
USt
0
Maximum number of steps that can be
performed.
LSt to 800 (* 10) For manual adjusting of the valve.
ESt
0
Extra steps in closing phase 0 to 255(*10)
Extra steps done by the valve during closing phase to assure the
valve closes completely
Sr
10
Step rate: is the speed to change step. A
too high value causes a wrong driving.
10 to 600 (steps/sec) For manual adjusting of the valve.
CPP
0
Current per phase during bipolar valve
driving.
0 to 100 (* 10mA) For manual adjusting of the valve.
CHd
0
Current per phase to maintain the actual
position (Holding current).
0 to 100 (* 10mA) For manual adjusting of the valve.
GtH
0.0
Autozero function 0÷15h
To prevent any possible wrong position caused by a long period
without closing the valve, the controller after gtH hours, as soon as
the opening open percentage is under 20%, will force complete
closer of the valve, and then will restart working.
REGULATION
SET -5.0
Set point LS÷US Target set point for temperature regulation
HY
2
Differential.
[0.1°C to 25.5°C]
[1°F to 45°F]
If
[CrE = n]
then
HY
is the hysteresis for ON/OFF thermoregulation.
If [CrE = Y] or [CrE = EUP] then HY is the proportional band for
temperature PI controller. On these cases the value should be
greater than 5°C.
int
150
Integral time for room temperature
regulation.
0 to 255s
This value is used only when
[CrE = Y]
or
[CrE = EUP]
. It’s the
integral time for thermoregulation: high values mean slower
regulation.
0 (zero) = no integral action.
CrE
n
Continuous regulation activation. n(0); Y(1); EUP(2)
With
[CrE = Y]
or
[CrE = EUP]
the regulation become
PI
,
HY
become a band and int an integral time.
n = standard regulation;
Y = continuous regulation, to be used only in centralized plants;
EUP = evaporator valves (see par. 16.2).
LS
-30.0
Minimum set point.
[-55.0°C to SET]
[-67°F to SET]
Set the minimum acceptable value for the set-point.
US
20.0
Maximum set point.
[SET to 150.0°C]
[SET to 302°F]
Set the maximum acceptable value for the set-point.
odS
0
Outputs activation delay at start up. 0 to 255min
This function is enabled at the initial start up of the instrument and
inhibits any output activation for the period of time set in this
parameter (N.B.: AUX and Light can work).
AC
0
Anti-short cycle delay. 0 to 60min Interval between the solenoid valve stop and the following restart.
CCt
0.0
Continuous cycle duration. 0.0 to 24h00min (144)
Compressor ON time during continuous cycle:
allows to set the
length of the continuous cycle: compressor stays on without
interruption for the CCt time. It can be used, for instance, when the
room is filled with new products.
Format: hours.10min, resolution: 10min.
CCS
0.0
Continuous cycle set point.
[-55.0°C to 150.0°C]
[-67°F to 302°F]
Set point for continuous cycle:
used value during the continuous
cycle.
Con
15
Compressor ON time with faulty probe. 0 to 255min
Solenoid valve ON time with faulty probe:
time during which the
solenoid valve is active in case of faulty thermostat probe. With
COn = 0 solenoid valve is always OFF.
CoF
30
Compressor OFF time with faulty probe. 0 to 255min
Solenoid valve OFF time with faulty probe:
time during which
the solenoid valve is off in case of faulty thermostat probe. With
COF = 0 solenoid valve is always active.
CF
°C
Temperature measurement unit. °C(0); °F(1)
°C
=
Celsius;
°F = Fahrenheit.
!!! WARNING !!!
When the measurement unit changes, all parameters with
temperature values will have to be checked.
PrU
rE
Pressure Mode. rE(0); Ab(1)
It defines the mode to evaluate the pressure values.
!!! WARNING !!!
PrU value is used for all the pressure parameters. If [PrU = rE] all
pressure parameters are in relative pressure unit, if [PrU = Ab] all
pressure parameters are in absolute pressure unit.