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3--3
T-334
COOL
HEAT DEFROST IN RANGE ALARM
SUPPLY RETURN
SETPOINT/Code
AIR TEMPERATURE/Data
Figure 3--3 Display Module
3.1.3 Controller
CAUTION
Do not remove wire harnesses from con-
troller modules unless you are grounded to
the unit frame with a static safe wrist strap.
CAUTION
Unplug all controller module wire harness
connectors before performing arc welding
on any part of the container.
CAUTION
Do not attempt to use an ML2i PC card in an
ML3 equipped unit. The PC cards are physi-
cally different and will result in damage to
the controller.
NOTE
Do not attempt to service the controller mod-
ules. Breaking the seal will void the warranty.
The Micro-Link 3 controller is a dual module
microprocessor as shown in Figure 3--4. It is fitted with
test points, harness connectors and a software card
programming port.
3.2 CONTROLLER SOFTWARE
The controller software is a custom designed program
that is subdivided into configuration software and
operational software. The controller software performs
the following functions:
a. Control supply or return air temperature to required
limits, provide modulated refrigeration operation,
economized operation, unloaded operation, electric
heat control and defrost. Defrost is performed to clear
build up of frost and ice and ensure proper air flow
across the coil.
b. Provide default independent readouts of set point and
supply or return air temperatures.
c. Provide ability to read and (if applicable) modify the
configuration software variables, operating software
Function Codes and Alarm Code indications.
d. Provide a Pre-Trip step-by-step checkout of refrigera-
tion unit performance including: proper component
operation, electronic and refrigeration control opera-
tion, heater operation, probe calibration, pressure
limiting and current limiting settings.
e. Provide battery powered ability to access or change
selected codes and set point without AC power con-
nected.
f. Provide the ability to reprogram the software through
the use of a memory card.
3.2.1 Configuration Software (Variables)
The configuration software is a variable listing of the
components available for use by the operational
software. This software is factory installed in
accordance with the equipment fitted and options listed
on the original purchase order. Changes to the
configuration software are required only when a new
controller has been installed or a physical change has
been made to the unit such as the addition or removal of
an option. A configuration variable list is provided in
Table 3--4. Change to the factory installed Configuration
Software is achieved via a configuration card or by
communications.
3.2.2 Operational Software (Function Codes)
The operational software is the actual operation
programming of the controller which activates or
deactivates components in accordance with current unit
operating conditions and operator selected modes of
operation.
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1
2
3
3
3
3
3
4
5
6
7
1. Mounting Screw
2. Micro-Link 3 Control/DataCORDER Module
3. Connectors
4. Test Points
5. Fuses
6. Control Circuit Power Connection
7. Software Programming Port
8. Battery Pack (Standard Location)
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