Emerson XM678D Manual

CONTROLLERS FOR MULTIPLEXED CABINETS
WITH STEPPER DRIVER INSIDE
XM678D
-MANUAL FOR THE SW REL. 2.8-
1. GENERAL WARNING ...................................................................................... 1
2. BEFORE PROCEEDING .................................................................................. 1
3. GENERAL DESCRIPTION ............................................................................... 1
4. QUICK REFERENCE GUIDE: HOW TO RUN THE SELF ADAPTIVE
REGULATION IN 5 STEPS. ............................................................................. 1
5. INSTALLATION AND MOUNTING ................................................................... 1
6. WIRING DIAGRAM AND CONNECTIONS ...................................................... 2
7. BATTERY BACK UP CONNECTION ............................................................... 3
8. USER INTERFACE........................................................................................... 4
9. HOW TO PROGRAM THE PARAMETERS (PR1 AND PR2) .......................... 4
10. FAST ACCESS MENU ..................................................................................... 4
11. MENU FOR MULTIMASTER FUNCTION: SEC .............................................. 5
12. COMMISSIONING ............................................................................................ 5
13. KIND OF REGULATION FOR SUPERHEAT: SELF ADAPTIVE OR MANUAL
OPERATING MODE ......................................................................................... 6
14. DISPLAY MESSAGES ..................................................................................... 6
15. USE OF THE PROGRAMMING HOT-KEY ...................................................... 7
16. CONTROLLING LOADS................................................................................... 7
17. TECHNICAL DATA ........................................................................................... 8
18. DEFAULT PARAMETER MAP ......................................................................... 9
1. GENERAL WARNING
1.1 PLEASE READ BEFORE USING THIS MANUAL
This manual is part of the product and should be kept near the instrument for easy

and quick reference.
 The instrument shall not be used for purposes different from those described
hereunder. It cannot be used as a safety device.
Check the application limits before proceeding.

Dixell Srl reserves the right to change the composition of its products, even

without notice, ensuring the same and unchanged functionality.
1.2 SAFETY PRECAUTIONS
 Check the supply voltage is correct before connecting the instrument.
 Do not expose to water or moisture: use the controller only within the operating
limits avoiding sudden temperature changes with high atmospheric humidity to
prevent formation of condensation
 Warning: disconnect all electrical connections before any kind of maintenance.
 Fit the probe where it is not accessible by the End User. The instrument must not
be opened.
In case of failure or faulty operation send the instrument back to the distributor or

to "Dixell S.r.l." (see address) with a detailed description of the fault.
 Consider the maximum current which can be applied to each relay (see Technical
Data).
Ensure that the wires for probes, loads and the power supply are separated and

far enough from each other, without crossing or intertwining.
2. BEFORE PROCEEDING
2.1 CHECK THE SW REL. OF THE XM678D
1. Look at the SW rel. of XM678D printed on the label of the controller.
2. If the SW release is 2.8, proceed with this manual otherwise contact Dixell
to get the right manual.
3. GENERAL DESCRIPTION
The XM678D is a microprocessor based controller for multiplexed cabinets suitable for
applications on medium or low temperature. It can be inserted in a proprietary LAN with
up to 8 different sections which can operate, depending on the programming, as stand
alone controllers or following the commands coming from the other sections. The
XM678D is provided with 6 relay outputs to control the solenoid valve, defrost - which
can be either electrical or hot gas - the evaporator fans, the lights, an auxiliary output
and an alarm output and with the stepper valve driver. The device is also equipped
with six probe inputs: for temperature control, for control the defrost end temperature,
for display and the fourth can be used for application with virtual probe or for inlet/outlet
air temperature measurement. Moreover, fifth and sixth probe are used to evaluate and
control the superheat. Finally, the XM678D is equipped with the three digital inputs
(free contact) fully configurable by parameters.
The device is equipped with the HOT-KEY connector that permits to be programmed
in a simple way. The optional direct serial output RS485 (ModBUS compatible) permits
a simple XWEB interfacing. RTC is available as options. The HOT-KEY connector can
be used to connect X-REP display (Depending on the model).
1592023140 XM678D GB r2.8 01.09.2017.docx
4. QUICK REFERENCE GUIDE: HOW TO RUN THE SELF
ADAPTIVE REGULATION IN 5 STEPS.
1. After wiring the XM678D, configure the type of valve, bipolar or unipolar, via
tEu (Default tEu = bP: bipolar) and
tEP (Default tEP =0) parameters or through the manual settings. See par. 6.3 for
details.
NOTE: for Alco EX4, EX5, EX6 tEP = 11
For EX3: tEP = 12
2. Set the proper gas via Fty parameter, among the following
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
Pre-set gas is R404A.
3. Configure the probes:
- Regulation and evaporator probe are preset as NTC. If another kind of
sensors is used, set it via P1c and P2c parameters.
- Superheat evaporator outlet probe is pre-set as Pt1000, if another kind
of sensor is used, set it via P6c parameter.
- The PP11 (-0.5÷11bar) is pre-set as pressure probe. It operates at relative
pressure (Pru = rE).
If you're using a ratiometric transducer, set P5c = 0-5, then use parameters
PA4 and P20 to set the range
NOTE: check the pressure gauge reading with the value of dPP, press the
UP arrow once to enter the Fast Access Menu. If ok, proceed; otherwise
solve the situation before proceeding acting on par. Pru, PA4 and P20.
4. Set the parameters for self adaptive regulation of superheat
NOTE: the parameters Pb (regulation band) and Int (integral time) are
automatically calculated by the controller
- Set CrE = no, this disable the continuos regulation of the temperature.
Default is CrE = no.
- Set SSH, superheating setpoint: a value between 4 and 8
acceptable.Default is SSH=8-
- Set AMS = y to start the self adaptive regulation. Default is AMS = y
- Set ATU = y to start the search of the lowest stable superheat. Default is
ATU = y. This function reduces automatically the setpoint in order to
optimize the use of the evaporator, keeping, at the same time, the
superheating regulation stable. The minimum allowed SH set point is
LSH+2°C.
- Set LSH, low superheating limit: a value between 2-4 is acceptable.
Default is LSH = 3
- Set SUb, pressure filter: Default is SUb = 10. The value can be increased
up to 20 in case of too fast response of the pressure variations.
5. Set the parameters for the temperature regulation
- Set the temperature setpoint. Default is -5°C
- Set the differential HY: Default is 2°C.
- If the capacity of the valve is higher than requested, it can be reduced by
the par. MNF (Default is 100). A proper setting of MnF will reduce the time
that the algorithm takes to reach the stability.
MNF value doesn't affect the band witdh
5. INSTALLATION AND MOUNTING
This device can operate without any user interface, but normal application is with Dixell
CX660 keyboard.
Figure 1a
Figure 1c
XM678D
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
The CX660 keyboard shall
be mounted on vertical panel,
in a 29x71 mm hole, and fixed
using the special bracket
supplied as shown in fig.
1a/1b. The temperature range
allowed for correct operation
is 0 to 60°C. Avoid places
subject to strong vibrations,
corrosive gases, excessive
dirt or humidity.
Figure 1b
The same recommendations
apply to probes. Let air
circulate by the cooling holes.
is
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