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3-5
62--611XX--20 (03/04)
e. Unlock the control panel
1.
2.
1. Press the CARRIER logo until the light is off.
2. The indicator goes off.
REMARK
IT IS NOT NECESSARY FOR THE COMPARTMENT TO
BE RUNNING IN ORDER TO MODIFY OR SEE THE SET-
POINT VALUE AND THE TEMPERATURE OF THE COM-
PARTMENT.
THE UNIT CAN BE SHUT DOWN BOTH WITH THE CAB
COMMAND AND THE GENERAL SWITCH.
3.5
CONTROL CIRCUIT OPERATION
3.5.1
Introduction
NOTE
To make it easier to locate the schematic components
referred to in the written text, the schematic in this
manual has map coordinates added to the margins.
These locations have also been added to the legend.
The controller boards shown on the electrical
schematic that interface with unit components are the
analog interface or processor board on the right and the
relay module on the left.
Connections to these boards are made through 3
multiple-pin plug connectors HC, HC2, & MP. The
address system (example HCD2-MPW2) indicates a
wire between plug HC, pin D2 and microprocessor MP
& pin W2.
The processor board connections are mainly inputs
and outputs for control switches, temperature sensors,
safety, andauto start functions that controlthe operation
of the unit. The processor board also controls the
operation of the relay board through plug connections.
The relay module, which contains plug-in
interchangeable relays provides the microprocessor
with a means for switching the unit components to
achieve a desired operating mode.
3.5.2
Temperature Control Logic
There are basically 3 modes of operation : Cool,
Heat or Defrost. Controller will automatically selectsthe
necessary mode to maintain box temperature at
setpoint.
There are two control ranges :
D
Frozen : setpoint < -12
_
C (54
_
F)
D
Perishable : setpoint > -12
_
C (54
_
F)
In the frozen range there are two control logic
depending if heat is allowed or not (refer to micro
configuration section 4.19.2, CNF-4).
There are also two operating modes :
D
Continuous
D
Start / Stop
a. Temperature Control / Continuous Mode
Diesel mode : since engine has two operating
speeds, there are four possible states :
D
High speed cool
D
Low speed cool
D
Low speed heat
D
High speed heat
Standby mode : there are two possible states :
D
Cool
D
Heat
See Figure 3-2 and Figure 3-4.
b. Temperature control / Start Stop
When start/stop mode is activated there is an
additional “off” state which correspond to unit shut off
when box temperature is closed to setpoint.
See Figure 3-1 and Figure 3-3.
c. Operation
Cool mode
: default mode for the micro.
Heat mode
: micro will energize MHR relay (which
controls the Main Heat Valve) via X1 output.
Depending upon which compartment requires heat
the HGR 1, 2 or 3 (or any combination of the 3 relays)