Rockwell Automation 1790P-T4T0 CompactBlock LDX I/O Thermocouple Modules - Manual (Page 88)

Publication 1790-UM003A-EN-P
D-4 Using Thermocouple Junctions
To prevent violation of channel-to-channel isolation:
• For multiple exposed junction thermocouples, do not allow the
measuring junctions to make direct contact with electrically
conductive process material.
• Preferably use a single exposed junction thermocouple with multiple
ungrounded junction thermocouples.
• Consider using all ungrounded junction thermocouples instead of the
exposed junction type.