General considerations, General considerations -4 – Rockwell Automation 1746-NT8 SLC 500 Thermocouple/mV Analog Input Module User Manual User Manual

Page 22

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Publication 1746-UM022B-EN-P - January 2005

2-4 Installing And Wiring Your Module

When using the BAS or KE module to supply power to a 1747-AIC
Link Coupler, the link coupler draws its power through the module.
The higher current drawn by the AIC at 24V dc is shown in the table
as BASn (BAS networked) and KEn (KE networked). Be sure to use
these current draw values if the application uses the BAS or KE
module in this way.

General Considerations

Most applications require installation in an industrial enclosure to
reduce the effects of electrical interference. Thermocouple inputs are
highly susceptible to electrical noises due to the small amplitudes of
their signal (microvolt/°C).

Group your modules to minimize adverse effects from radiated
electrical noise and heat. Consider the following conditions when
selecting a slot for the thermocouple module. Position the module:

in a slot away from sources of electrical noise such as recontact
switches, relays, and AC motor drives

away from modules which generate significant radiated heat,
such as the 32-point I/O modules

In addition, route shielded twisted pair thermocouple or millivolt
input wiring away from any high voltage I/O wiring.

Remember that in a modular system, the processor or communications
adapter always occupies the first slot of the chassis.

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