Rockwell Automation 1746-NT8 SLC 500 Thermocouple/mV Analog Input Module User Manual - Manual (Page 94)

Publication 1746-UM022B-EN-P - January 2005
B-2 Using Grounded Junction, Ungrounded Junction, and Exposed Junction Thermocouples
Grounded Junction
Ungrounded (Insulated) Junction
Exposed Junction
Isolation The 1746-NT8 module provides the following electrical isolation:
•
12.5V dc electrical isolation channel-to-channel
•
500V dc electrical isolation channel-to-chassis ground
•
500V dc electrical isolation channel-to-backplane
Care must be taken when choosing a thermocouple type and
connecting it to the 1746-NT8 module from the environment being
measured. If adequate precautions are not taken for a given
thermocouple type, the electrical isolation of the 1746-NT8 module
may be compromised.
Extension Wire
Metal Sheath
Measuring Junction is
connected to sheath
Measuring Junction is
isolated from sheath
Measuring Junction
has no sheath