Reference Temperature Sensing with the HP E1313
The HP E1313 can have two terminal modules installed. To obtain the
specified accuracy through each terminal module, the temperature of both
must be sensed. A sense channel is required on each terminal module which
leaves 31 channels on each terminal module for thermocouple and other
measurements. Figure 2-5 shows how the HP E1313 internally connects its
single current source to the two reference thermistors in series. Note that a
diode provides a current path when terminal module 2 is absent, but that
terminal module 1 must be in place and configured properly to provide a
current path to terminal module 2. Figure 2-7 shows sensing the on-board
thermistor. Refer to Figure 2-6 for remote thermistor connection.
On-Board Current Source
HP E1313 Module
Terminal Module 1 (Chs 0 - 31)
Field Wiring
REM
LCL
JM1
HTI
LTI
HTS
LTS
Hnn
Lnn
Any Sense Channel on Terminal Module 1
On-Board Current Source Return
HP E1313 Module
Terminal Module 2 (Chs 32 - 63)
Field Wiring
REM
LCL
JM1
HTI
LTI
HTS
LTS
Hnn
Lnn
Any Sense Channel on Terminal Module 2
Figure 2-5. HP E1313 Reference Temperature Circuit
40 Field Wiring
Chapter 2
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