Installation Instructions User Manual

14 SLC™ 500 4-Channel Thermocouple/mV Input Module

Publication 1746-IN010D-EN-P - June 2004

– If millivolt inputs are used, the terminal should be biased to a level

within 2V of the signal of interest. Use 10KΩ resistors to create a resistive

voltage divider as shown in the following circuit diagram.

• Ground the shield drain wire at one end only. The preferred location is to

the same point as the sensor ground reference.

– For grounded thermocouples or mV sensors, this is at the sensor.

– For insulated/ungrounded thermocouples, this is at the module.

– Refer to IEEE Std. 518, Section 6.4.2.7 or contact your sensor

manufacturer for additional details.

• If it is necessary to connect the shield at the module, each input channel has

a convenient shield connection screw terminal that provides a connection to

chassis ground. All shields are internally connected, so any shield terminal

can be used with channels 0-3. For maximum noise reduction, one shield

terminal must be connected to earth ground potential, i.e. mounting bolt on

1746 chassis.

TIP

The Series A 1746-NT4 does not have an ANALOG COM

terminal and cannot be used with multiple grounded and/or

exposed thermocouples that touch electrically conductive

material. The Series A can be used with a single grounded

and/or exposed thermocouple that touches electrically

conductive material, or multiple grounded thermocouples that

have the protective sheath made of an electrically

non-conductive material such as ceramic.

Strain Gauge

Bridge

NT4

Vcc

10K Ω

variable

fixed

Input

(CHL 0, CHL 1, CHL

2, CHL 3)

Analog Com