7
Motor temperature sensor
This sensor is used to control the motor temperature of each
compressor.
Temperature setpoint reset sensor (EMM)
This 4-20 mA space temperature sensor can be installed
remotely from the unit. It is used to reset the setpoint on the
unit.
Master/slave water sensor (optional)
The. water. temperature. sensor. is. used. for. master/slave.
assembly control.
3.7 - Actuators
Water pumps
The controller can regulate one condenser pump as well as
one.or.two.evaporator.pumps.and.takes.care.of.the.automatic.
changeover.between.these.pumps.(units.with.two.pumps.only).
Electronic Expansion Valve
The.electronic.expansion.valve.(EXV).is.used.to.adjust.the.
refrigerant.flow.to.changes.in.the.operating.conditions.of.the.
machine..To. adjust. the. refrigerant. flow,. a. piston. moves.
constantly. up. or. down. to. vary. the. cross-section. of. the.
refrigerant.path..This.piston.is.driven.by.an.electronically.
controlled linear stepper motor. The high degree of accuracy
with.which.the.piston.is.positioned.provides.precise.control.
of.the.refrigerant.flow.
Water flow switch
The.water.flow.switch.configuration.allows.for.the.automatic.
control.of.the.minimum.water.flow.setpoint.of.the.water.flow.
switch..The. configuration. depends. on. the. unit. size. and. is.
made automatically at the start-up. If the measured water
flow.rate.in.the.water.loop.is.lower.than.the.configured.flow.
rate, the alarm condition shuts off the unit.
3.8 - Connections at the customer terminal block
Connections.available.at.the.user.terminal.block.may.vary.
depending on the selected options.
IMPORTANT:
Some contacts can be accessed only when
the unit operates in Remote mode.
3.8.1 - Terminal block connections
The following table summarizes connections at the user
terminal block.
Description
Board
Connector
Remarks
Remote on/off contact
SIOB, cir A
DI-01; 32-33
Used for the unit on/off control if the unit is in Remote mode
Remote setpoint contact
SIOB, cir A
DI-02; 65-66
Used to control the setpoint
Demand limit contact
SIOB, cir A
DI-03; 63-64
Used to control demand limit
Remote heat/cool contact
SIOB, cir A
DI-04; 73-74
Used to select heat/cool mode
Alarm relay
SIOB, cir A
DO-05; 30A-31A
Indicates alarms
Running relay
SIOB, cir A
DO-06; 37-38
Indicates if the unit is ready to start or operating
Occupancy override
SIOB, EMM
DI-01; 77-78
Enables to switch between occupied (closed contact) and unoccupied
mode (open contact)
Demand limit contact 2
SIOB, EMM
DI-02; 73A-74A
Used to control demand limit
Customer interlock
SIOB, EMM
DI-03; 34A-35A
Used for the customer safety loops
Ice done contact
SIOB, EMM
DI-04; 75-76
Used for ice storage control
Unit partially shutdown
SIOB, EMM
DO-05; 30B-31B
Indicates the shutdown of one of the circuits
Unit shut down
SIOB, EMM
DO-06; 30-31
Indicates the unit shutdown
3.8.2 - Volt-free contact (on/off and cooling/heating)
On/off contacts and cooling/heating contacts are as follows:
Off
Cooling
Heating
On/Off contact
open
closed
closed
Cooling/Heating contact
open
open
closed
Off:
Unit is stopped
Cooling: Unit is allowed to start in Cooling
Heating: Unit is allowed to start in Heating
3.8.3 - Volt-free setpoint selection contact
When.the.unit.is.under.remote.control,.the.volt-free.contact.
is.used.to.determine.the.active.setpoint..This.dry.contact.is.
used to switch between setpoints.
Setpoint
contact
Active setpoint
Cooling
Heating
CSP1
CSP2
HSP1
HSP2
SP_SW
open
close
open
close
csp = cooling setpoint
hsp = heating setpoint
3.8.4 - Volt-free demand limit selection contact
Up to two dry contacts can be used to limit unit capacity
(LIM_SW1 and LIM_SW2). The second contact (LIM_SW2)
is. available. only. for. units. with. the. energy. management.
module (EMM).
Capacity limitation with two contacts is as follows:
100%
Limit 1
Limit 2
Limit 3
Demand limit 1 contact
(LIM_SW1)
open
closed
open
closed
Demand limit 2 contact
(LIM_SW2)
open
open
closed
closed
3.8.5 - Ice storage (EMM)
For units with EMM option, the control includes an additional
setpoint (“ice setpoint”) used for ice storage control.
Cooling setpoint
CSP1
CSP2
ICE_STP
Occupancy schedule
occupied
unoccupied
unoccupied
Ice done switch
open/closed
closed
open
csp = cooling setpoint
ice_stp = ice setpoint
