Connecting The Sensor; Connecting The Measuring Unit - Endress+Hauser iTEMP HART TMT162 Bedienungsanleitung

TMT162
Endress+Hauser
4.2

Connecting the sensor

When connecting 2 sensors ensure that there is no galvanic connection between the
sensors (e.g. grounded duplex thermocouples). The resulting equalizing currents distort the
measurements considerably. In this situation, the sensors have to be galvanically isolated
from one another by connecting each sensor separately to a field transmitter. The device
provides sufficient galvanic isolation (> 2 kV AC) between the input and output.
For sensor connection terminal layout please see Fig. 5. On two sensor inputs the following
connection combinations are possible:
Sensor 1:
RTD 2-wire
Sensor 2:
RTD 2-wire
Sensor 2:
RTD 3-wire
Sensor 2:
RTD 4-wire
Sensor 2:
TC connection
There are special cable entries available as accessories when connecting 2 sensors (not for XP
instrumentation). These can be found on → Page 85.
4.3

Connecting the measuring unit

NOTICE
Electronic parts may be damaged
► Switch off power supply before installing or connecting the device. Failure to observe this may
result in destruction of parts of the electronics.
► If the device has not been grounded as a result of the housing being installed, grounding it via
one of the ground screws is recommended.
®
4.3.1 HART connection
communication resistance is not built into the power supply, a 250 Ω
®
If the HART
communication resistor must be fitted into the 2-wire supply lines.
For connection hints, please take special notice of the documentation supplied by the
®
HART Communication Foundation, specifically HCF LIT 20: "HART, a technical
overview".
Sensor 1:
RTD 3-wire
Yes Yes
Yes Yes
No No
Yes Yes
Sensor 1: Sensor 1:
RTD 4-wire TC connection
No Yes
No Yes
No No
Yes Yes
Wiring
65