4 0
TRM138
A4.1.
With a twowire circuit the transducer readings depend upon variations of the
environment temperature along the “transducerinstrument” communication line. The difference
between the actual and indicated values can be observed after increase of the temperature
measurement range, as well as at increase of the communication line resistance. Prior to operating
the instruments the following steps must be completed.
A4.2.
Connect the transducers to the corresponding input of the instrument over a twowire
circuit, as per figure P.4.1.
A4.3.
Instead of temperature transducer connect resistance box of MSP63 type (or similar,
with at least 0.05 accuracy class) to opposite ends of “transducerinstrument” line.
A4.4.
At the resistance box set the same value
as for the resistive temperature transducer at 0 °C
temperature (50.00; 53.00; or 100.00 Ohm, depending
on a type of the transducer used).
A4.5.
Power on the instrument. Based on
DI1
indications for the corresponding channel record the
temperature value deviated from 0 °C. The obtained
deviation must be positive, its value depends upon
the “transducerinstrument” communication line
resistance.
A4.6.
For this transducer set “shift of characteristic” correction value in
in.SH(PL1)
parameter, this value shall be the same as the temperature deviation value but the opposite
sighting.
A4.7.
Check the correction results by measuring resistance at the box, and then set
OPERATION mode for the instrument and make sure that DI1 indicator readings for the
corresponding channel are equal to 0 °C (with accuracy not less than 0.2 °C).
A4.8.
Power off the instrument. Disconnect the “transducerinstrument” communication line
from the resistive box, and connect it to the temperature transducer.
A4.9.
In the similar manner (see A4.2 – A4.8) correct the rest resistive temperature
transducers, which shall be connected to the instrument via a twowire circuit. Any connections of
the transducers must be carried out after the instrument is powered off.
Connecting resistive temperature transducers
over a twowire circuit
Appendix 4
Figure A4.1. Connection diagram for
resistive temperature transducer over
a twowire circuit.
Содержание TPM138
Страница 23: ...22 TRM138 Setting up Procedures Section 6 Figure 16 Programmed parameters setting diagram...
Страница 24: ...23 TRM138 Section 6 Setting up Procedures...
Страница 30: ...29 TRM138 Appendix 1 Dimensional drawing...
Страница 31: ...30 TRM138 Instrument connection Appendix 2 Figure A2 1 Instrument terminal block contacts arrangement diagram...
Страница 35: ...34 TRM138 Figure A2 10 Example of connection of various type transducers Instrument connection Appendix 2...
