Campbell CS240, Руководство по эксплуатации продукта

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l
Use low capacitance, low resistance, screened cable (as fitted by Campbell Scientific) to
reach distances of several hundred meters.
l
Ensure that the power ground cable has low resistance and is connected to the same
ground reference as the data logger control terminals.
l
Be aware that daisy-chaining sensors reduces the maximum cable length roughly in
proportion to the number of sensors connected in parallel.
8.3 Modbus register map
Table 8-1 (p. 18) provides the input register map (function code 4) and Table 8-2 (p. 19) provides
the holding register map (functions 3, 6, and 16).
Table 8-1: Input register map
Input register Value
Modbus
data type
Description
30001 Serial number
Float
1
Specifies the sensor serial number
assigned by the factory
30003 Temperature
Float
1
The CS240DM measures temperature
by using a 4-wire configuration. The
stored value is in degrees Celsius.
30005 Counter
Float
1
The counter provides an indicator
that the sensor is actively taking
measurements. This value will
increment once per measurement,
rolling over at 10,000.
30007 Sensor status
Float
1
0 = good
1 = open/short
30009
Temperature
range check
Float
1
0 = good/in range
1 = out of range
1
Modbus float is a 32-bit integer.
CS240 and CS240DM PT-1000 Class A, Back-of-Module Temperature Sensors 18