RSTAR Affinity
Data Logger
Installation Guide
PSM0003A
RST Instruments Ltd.
Page 18
Appendix C:
I
NSTRUMENT
I
NTERFACE
M
ODULE
V
IBRATING
W
IRE AND
T
HERMISTOR
IIM
The Vibrating Wire and Thermistor IIM (VW/TH) may be configured to support up
to two sensors which may be a combination of:
two vibrating wire sensors
two thermistor sensors
one vibrating wire and one thermistor sensor
This IIM module is designed for a vibrating wire piezometer with a resonant
frequency between 2,000 and 3,500 Hz. This IIM module converts the
thermistor’s resistance in the range of 20 ohms to 200,000 ohms with accuracy of
0.1%.
The pin assignments are:
Pin 1 – shield
Pin 2, 3 – thermistor or vibrating wire piezometer
Pin 4, 5 – thermistor or vibrating wire piezometer
T
HERMISTOR AND
T
HERMISTOR
IIM
The Thermistor and Thermistor IIM (TH/TH) supports up to two thermistor
sensors. This IIM module converts thermistor’s resistance in the range of 20
ohms to 200,000 ohms with accuracy of 0.1%.
The pin assignments are:
Pin 1 – shield
Pin 2, 3 – first thermistor
Pin 4, 5 – second thermistor
RS-485
IIM
The RS-485 IIM connects to an RS-485 instrument that adheres to the RS-485
electrical standard. This IIM may be configured to process data communication
rate between 1,200 and 115,200 Baud in half duplex operation. This IIM also has
an op12V DC output.
The pin assignments are:
Pin 1 – shield
Pin 2 – ground
Pin 3 - +12V DC power output
Pin 4 – RS-485 B (inverting pin)
Pin 5 – RS-485 A (non-inverting pin)
D
UAL
4-20
MA
IIM
The Dual 4-20MA IIM may be configured to support up to two separate 4-20 mA
sensors that supports a 4-20mA device. An 82-ohm series shunt resistance
converts the current sense to a voltage.
