XT Controllers for NLV-CN Compressors
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4.2.
Modbus
Addressing
The controller can be mounted in a Modbus network of up to 99 controllers. To recognize the different
controllers on the network, each controller must have its own, unique address.
Functional description:
The Modbus address can be set either via the Tool4Cool
®
service tool or the local display. If the controller
has a password, this must be entered first.
The address range can be set in the range from 1 to 99. Parameter “Modbus address” (o03).
Restrictions:
If the Modbus address is modified via the Tool4Cool
®
, the user must ensure that the new address is within
the setting range of the Tool4Cool
®
, otherwise communication to the controller will be lost, until the
correct address range has been selected on Tool4Cool
®
, and the network has been scanned again.
Parameter Function Code Min. Max.
Default
Setting
Modbus address o03 0 99 1
Modbus baud rate
1 = 9600
2 = 19200
o04 1 2 2
4.3.
Temperature
Acquisition
The temperature acquisition system handles all the temperature measuring related issues, such as
sensor selection, weighting of sensors, and sensor error detection.
The NLV controller has 4 sensor inputs. The S1, S2, S3, and S4 sensors are compatible with the 5K NTC
sensors. All sensors are NTC sensors. Please refer to the chapter Temperature Sensors.
Sensor configuration:
The sensors are configured by software parameters in the function where it is used.
For instance, the defrost sensor is configured in the defrost control menu. Temperature control sensors
are configured for several functions, such as capacity control, alarms, display, Modbus reading, or
temperature logging.
Generally, the S1 and S2 sensors are used to measure the cabinet temperature, S4 for controlling defrost,
and S3 for product temperature or condenser fan control.
Offset adjustment of temperature measurements:
To compensate for measuring errors or wrong placement of the sensor, all sensors include an offset
adjustment. With the parameter “Fx temperature offset” (r09), (r10), (r55), and (r57) it is possible to adjust
the respective temperature measurements from -10 to 10 K.
Filtering of temperature measurements:
Furthermore all temperature measurements can be filtered with the parameter “Filter constant for Txx”
(o90 to o96), which can be used for very unstable or fluctuating temperatures.
>
0: no damping, (fastest updating of the read out)
>
10: 0.01 K/sec (slowest updating of the read out)
Weighting of sensors:
In some cases, it might be necessary to use 2 sensors at different locations, to achieve the correct
temperature measurement. For instance, top-bottom, left-right, or evaporator inlet – outlet.
Different weighting (balancing) can be set for sensor S1 and S2 at day and night, for alarms, temperature
control, and display.
Weighting is done by setting a parameter between 0 to 100%, depending on how much influence the
sensors should have on the temperature measurement.
If the parameter is set to 0%, only S1 is used, if set to 100%, only S2 is used.
If 50%, both S1 and S2 will have the same influence.
Example: S1 is -22°C and S2 is -18°C. If weighting (w) set to 25%, the resulting temperature is -21°C.
Parameter Function Code
Multiple
Apps
Min. Max.
Default
Setting
Unit
S1 temperature offset r10 x -10 10 0 °K
S2 temperature offset r09 x -10 10 0 °K
S4 temperature offset r57 x -10 10 0 °K
S3 temperature offset r55 x -10 10 0 °K
S1/S2 temperature offset r04 x -10 10 0 °K
Filter constant for T
act
o90 x 0 (none) 0.10 0.01 K/sec.
Filter constant for T
alarm
o91 x 0 (none) 0.10 0.01 K/sec.
Filter constant for S1/S2 o92 x 0 (none) 0.10 0.01 K/sec.
Filter constant for S4 o94 x 0 (none) 0.10 0.01 K/sec.
Filter constant for S3 o96 x 0 (none) 0.10 0.01 K/sec.
Parameter Function Code
Multiple
Apps
Min. Max.
Default
Setting
Unit
Definition and weighting, of sensors S1 and
S2 when daytime mode is present (100%=S2,
0%=S1)
r15 x 0 100 100 %
Definition and weighting, of sensors S1 and
S2 when nighttime mode is present (100%=S2,
0%=S1)
r61 x 0 100 100 %
Definition and weighting, of sensors S1 and S2
T
alarm
(100%=S2, 0%=S1)
A36 x 0 100 100 %
Definition and weighting, of sensors S1 and S2
for S1/S2 (100%=S2, 0%=S1)
o17 x 0 100 100 %
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