Azbil ATT082, Краткое руководство пользователя, Страница: 16 / 32

12
Chapter 5 Wiring
5-2. Connecting the sensor cables
Refer to Terminal assignment of head transmitter, shown on 5-1. Quick wiring guide.
Handling Precautions:
When connecting 2 sensors ensure that there is no galvanic connection
between the sensors (e.g. caused by sensor elements that are not isolated from
the thermowell). The resulting equalizing currents distort the measurements
considerably.
>> The sensors must remain galvanically isolated from one another by con-
necting each sensor separately to a transmitter. The transmitter provides
sufficient galvanic isolation (>2 kV AC) between the input and output.
The following connection combinations are possible when both sensor inputs are assigned:
Sensor input 1
RTD or resistance transmitter
Thermocouple (TC),
voltage transmitter
2- wire 3- wire 4- wire
Sensor
input 2
RTD or
resistance
transmitter
2-wire
✓ ✓
—
✓
3-wire
✓ ✓ *
—
✓ *
4-wire — — — —
Thermocouple (TC),
voltage transmitter
✓ ✓
*
✓ ✓
*
* Refer to CM2-ATT082-2003, Functional Safety Manual.