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
C
ove
ON
BOARD
ON
BOARD
ON
BOARD
J1
J1
r
ONBOARD
PlacebothJ1jumpershereto
connectcu rrent source to
on-boardthermis tor RT1.Sense
RT1by connecting a ny sense
channelsto terminals HTS and
LTS.
REMote
Placeboth J1
j
umpershere to
routecurrent source to termin als
HTIand LTI. Connect these
terminalsto remote thermistor o
r
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