TM4 - Measuring module for soil tensiometer

TM4 Vyhodnocovací modul pro půdní tenzometry TMS11A

Basic description

The TM4 evaluation module corrects the absolute pressure obtained from the TMS11A soil tensiometer by the value of the atmospheric air pressure. The atmospheric air pressure sensor is located in the TM4 module. The resulting calculated vacuum-overpressure in the soil is transmitted to the connected recording unit (datalogger) via the RS485 bus.

Together with the values of the corrected pressures of the connected soil tensiometer, the soil temperatures measured by the individual soil tensiometer, the temperature inside the TM4 evaluation module and the atmospheric air pressure can also be read from the TM4 evaluation module.

Up to 4 TMS11A soil tensiometer can be connected to one TM4 module at the same time. The length of the connecting cable between the soil tensiometer and the module TM4 can be up to 15 m.

Electrical connection of the TM4 module to FIEDLER units

The TM4 evaluation module is connected to the FIEDLER recording units via the power supply and communication cable, which are equipped with an RS485 serial interface (M4016, STELA, H1, H7, Q2, H40, ... units).

The current consumption of the TM4 module at the + Unap terminal does not exceed 5 mA and practically does not load the power supply in the recording unit, because the module is powered only for a short time with the frequency given by the set measurement interval. 


zapojení kabelu TM4

Technical parameters

Supply voltage: 6 ... 14 VDC / Imax <5 mA

Data output: RS485 (FINET, Modbus RTU)

Occupancy of internal channels:

K1 to K4: measured and calculated corrected soil suction pressure at inputs 1 to 4

K5 to K8: soil temperature from soil tensiometers at inputs 1 to 4

K9: atmospheric air pressure measured by the TM4 module

K10: temperature inside the TM4 module

Number of inputs for TMS11A connection: 4

Response time from power on: <1 s

Operating temperature range: -30 to +50 °C

Dimensions (without holder): 90 x 80 x 30 mm

Weight: (without holder): 440 g

Protection: IP66


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