Operating instructions

TM 11574A-OI
2-19
V. CONTROLLER AND SOFTWARE FUNCTIONS
2-13. Check Controller Function Codes
The controller software is a custom designed program that is subdivided into the configuration
software and the operational software. The controller software performs the following functions:
a. Control supply or return air temperature to required limits, provide modulated refrigeration
control, electric heat control and defrost. Defrost is performed to clear buildup of frost and ice
from the coil to ensure continuous conditioned air delivery to the load.
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 refrigeration unit performance, including proper
component operation, electronic and refrigeration control operation, heater operation, probe
calibration, pressure limiting, and current limiting settings.
e. Provide battery-powered ability to access or change selected codes and set points without
AC power connected.
f. Provide the ability to reprogram the software through the use of a memory card.
(1) Configuration Software (Configuration 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 the original software has been lost 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 2-2. A change to the factory-installed configuration
software is achieved via a configuration card.
(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 operation conditions
and operator selected modes of operation. The programming is divided into function
codes. Some of the codes are read only while the remaining codes may be user
configured. The value of the user configurable codes can be assigned in accordance
with user desired mode of operation. A list of the function codes is provided in Table 2-5.
To access the function codes, perform the following:
1. Press the CODE SELECT key, then press an arrow key until the left window displays
the desired code number.
2. The right window will display the value of this item for five seconds before returning to
the normal display mode.
3. If a longer time is desired, press the ENTER key to extend the time to 30 seconds.