Field Wiring 49Chapter 2
Connecting the On-Board Thermistor
The following figures show how to use the VT1422A to make temperature
measurements using the on-board Thermistor or a remote reference sensor.
The Thermistor is used for reference junction temperature sensing for thermocouple
measurements. Figure 2-12 shows the configuration for the VT1422A’s Spring
Terminal Module, Figure 2-6 shows the configuration for the Screw Terminal
Module. See “Reference Temperature Sensing with the VT1422A” on page 44 for
a schematic diagram of the reference connections.
Under
ove
ON
BOARD
ON
BOARD
ON
BOARD
J1
J1
r
ON BOARD
PlacebothJ1jumpershereto
connect current source to
on-board thermistor RT1. Sense
RT1 by connecting any sense
channels to terminals HTS and
LTS.
REMote
Place both J1
umpers here to
route current source to terminals
HTI and LTI. Connect these
terminals to remote thermistor o
RTD. Sense with any sense
channel.
REM
REM
SCP 0
REM
J1
SCP 4
SCP 5 SCP 6
SCP 7
SCP 1
SCP 2
SCP 3
See Figure 2-13 on page 50 to remove the cover
Figure 2-12. Temperature Sensing for the Terminal Module
