1-16
Revised 8-6-93
de-energized to allow the system to recover. The
out-of-range timer starts as soon as the temperature
exceeds the in-range tolerance value set by code Cd29.
Cooling capacity reduction by modulation is the
same as described for the conventional operating mode
when any of the above 4 conditions are invalid.
With set points below ---10
_
C (+14
_
F), operation is
the same as previously described for conventional mode
--- heating and dehumidification are locked out.
b. Frozen range below ---10
_
C (+14
_
F)
The return air probe is used for control and is so
indicated by the LED on the display board.
The Frozen temperature range is not sensitive to
minor temperature changes. The method of temperature
control employed in this range takes advantage of this
fact, to greatly improve the energy efficiency of the
system. Temperature control in the Frozen range
below
---10
_
C (+14
_
F)
is accomplished by cycling the
compressor on and off as the load demand requires.
If the return air temperature in the container drops
0.2
_
C (0.4
_
F) below the set point temperature, the
compressor is cycled off. When the temperature is
greater than 0.2
_
C (0.4
_
F) above set point and 6 minute
time delay has been met, the compressor will restart. The
system will always operate at full capacity which means
both the solenoid modulating (SMV) and suction
solenoid (SSV) valves are fully open unless suction
solenoid override is activated. See section 1.11 for
explanation of suction solenoid override.
The temperature control is still within the tight
limits. Conditions could exist, however, which may cause
the return air temperature to rise rapidly. Such a case
would be the initial reaching of set point temperature.
When the set point temperature is initially reached, the
load may still be warmer than the set point temperature.
This could cause a rapid rise in return air temperature
when the compressor is off, causing a rapid restart or
on/off cycling of the compressor which is undesirable. To
prevent this from occurring, a 6 minute compressor off
time must be satisfied before the compressor will restart.
Under a condition of a rapidly changing return air
temperature, the time delay may allow the return air
temperature to rise slightly more than 0.2
_
C (0.4
_
F)
above the set point temperature before the compressor
can restart.
1.13.4 Function and Data Codes
There are 30 functions which the operator may
access to examine the operating status of the unit. To
access these functions, perform the following: Press the
code select
key, press an arrow key until the left window
displays the desired code number (see Table 1-4). The
right window will display the value of this item for 5
seconds before returning to the normal display mode. If a
longer time is desired, pressing the
Enter
key will extend
the time to 30 seconds after the last pressing of the
Enter
key. Below is an explanation of all Function codes.
Table 1-4. Function Code Assignments
FUNCTION
CODE
DATA
Display Only Functions
Cd00
Alarm List
Cd01
Suction Modulation Valve Opening (%)
D
Cd02
Quench Valve (Open --- Closed)
Cd03
Suction Solenoid Valve (Open --- Closed)
Cd04
Line Current, Phase A
Cd05
Line Current, Phase B
Cd06
Line Current, Phase C
Cd07
Supply Voltage
Cd08
Supply Frequency
Cd09
Ambient Air Temperature
Cd10
Compressor Suction Temperature
D
Cd11
Compressor Discharge Temperature
D
Cd12
Saturated Condenser Temperature
D
Cd13
Compressor Discharge Pressure
Cd14
Future Expansion
Cd15
Future Expansion
Cd16
Compressor Motor Hour Meter
D
Cd17
Hours Since Last Trip Start
Cd18
Software Revision Number
D
Cd19
Serial # (First 4 of 8)
D
Cd20
Serial # (Second 4 of 8)
D
Cd21
USDA #1 Probe Temperature
D
Cd22
USDA #2 Probe Temperature
D
Cd23
Secondary Return Air Temperature
(USDA)
Cd24
Secondary Supply Air Temperature
Cd25
Time Remaining Until Defrost
Display/Select Functions
Cd26
Defrost Interval
Cd27
Temperature Units (
_
C or
_
F)
Cd28
Failure Action
Cd29
In-Range Tolerance
Cd30
Stagger Start Offset Time
Cd31
Current Limit
Cd32
Dehumidification Control (Optional)
D
= Codes that are NOT APPLICABLE for some units
Code 00 --- Alarm List Display Selection
(See Table 1-3 and Table 1-4)
This process will allow the user to examine all alarms
that are written in the list. To notify the user of the top of
the list, “Strt” is displayed. By using the arrow keys, the
entire list may be displayed. Each alarm number will be
preceded by a status indication, “IA” for inactive alarm
and “AA” for active alarm. See Alarm section.
Code 01 --- Suction Modulation Valve Opening (%)
The suction modulation valve (SMV) is a normally
open valve which restricts flow of refrigerant to the
compressor when energized by a pulse width modulated
(PWM) output. The amount of closing of the valve is
proportional to the applied current over the range of 0.2
Downloaded from
