dIXEL
Operating instruction manual
1592019010
1592019010 XEV11D GB r1.2 2008.07.08.doc
XEV11D
1/4
XEV11D
ON-OFF ELECTRONIC EXPANSION VALVE DRIVERS
CONTENTS
1.
General warning _____________________________________________________1
2.
General description ___________________________________________________1
3.
Regulation __________________________________________________________1
4.
Front panel _________________________________________________________1
5.
User interface _______________________________________________________2
6.
Parameters list ______________________________________________________2
7.
Digital inputs ________________________________________________________3
8.
Plant starting function _________________________________________________3
9.
Electrical connections _________________________________________________3
10.
RS485 serial line _____________________________________________________3
11.
How to use the HOT KEY ______________________________________________3
12.
Display messages ____________________________________________________3
13.
Technical data _______________________________________________________3
14.
Wiring connections ___________________________________________________3
15.
Standard values _____________________________________________________3
16.
Example of application ________________________________________________4
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.
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.p.A.” (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.
•
In case of applications in industrial environments, the use of mains filters (our mod. FT1) in
parallel with inductive loads could be useful.
2.
GENERAL DESCRIPTION
The
XEV11D
module is able to drive
ON/OFF electronic expansion valves
. This module permits to
regulate the superheat (SH) of the fluid that runs into refrigerating unit in order to obtain optimized
performance and a climatic or load conditions independent functioning.
XEV11D
modules are
equipped with two probe inputs, one for 4÷20mA or 0÷5V pressure transducer and another for Pt1000
or NTC temperature probe. A LAN connection permits to transmit the pressure signal to all other XEV
modules in order to use only one pressure transducer in multiplexed cabinet applications. There are
also two configurable digital inputs, one of them must be configured to get cooling request. The other
digital input can be used to signal to the instrument that defrost is in progress. To complete instrument
equipment, a RS485 serial link permits to connect XEV11D to
dIXEL
monitoring and supervising
systems.
XEV11D
can be programmed with
KB1-PRG
remote keyboard or with Dixell HOT-KEY.
3.
REGULATION
The superheat regulation is performed only when the cooling request is active. The following scheme
shows how device reads the request of cooling:
The regulation is obtained with
PI
controller that it changes the valve opening percentage. Opening
percentage is obtained from average of Opening Time respect to
CyP
time period like following
diagram:
With opening percentage we mean percentage of cycle period where valve is open. For example, if
CyP=6s and we say: “The valve opening percentage is 50%”; we mean the valve is opened for 3s
during cycle period.
3.1
INJECTION SIGNALLING
The graph illustrates how to work the function for injection problems signalling. When superheat stays
in
dSH
(
d
elta
S
uper
H
eat) band and valve increases continuously its opening more than
dOP
(
d
elta
OP
ening) for
ind
time (
in
jection
d
elay) the driver signals a gas problem. When this event occurs, the
behaviour of the valve can be fitted to your demand. Trough
inb
(
in
jection
b
ehaviour) parameter you
can choose if the valve have to close completely (inb=cL)
, or if regulation have to continue normally
with PI.
1
4.
FRONT PANEL
XEV11D
To display and to modify the set
point. In programming mode it
selects a parameter or it
confirms a value.
In programming mode it slides
the codes of the parameters or it
increases their values.
In programming mode it slides
the codes of parameters or it
decreases their values.
KB1-PRG
KEYS COMBINATIONS
+
To lock or to unlock the keyboard
.
+
To enter to programming mode.
+
Press and hold this keys combination about 5 seconds to activate
valve ON function (described in Plant start section). If you are in
programming mode this combination permits to leave it.
4.1
XEV11D LEDS
XEV11D has four LEDs. Their meaning is described in the following table:
LED
MODE
Function
POWER
ON
The power supply is ok
TX/RX
OFF
There is no RS485 activity
TX/RX
BLINKING
Serial communication present
VALVE
ON
Valve is opened
