Linear resistance input
SITRANS TH320/TR320/TF320
SITRANS TH420/TR420/TF420
Cable, wire-wire capacity
Max. 30 nF (lin. R > 400 Ω)
Max. 50 nF (lin. R ≤400 Ω)
Fault detection, programmable
None, short-circuited, broken, short-circuited or broken
12.2.6.4
Potentiometer
Potentiometer input
Resistance range
10 Ω ... 100 kΩ
Input range
0 ... 100%
Minimum measured span
10%
Connection type
3-wire, 4-wire or 5-wire
5-wire only for devices with two inputs
Wire resistance per wire (max.)
50 Ω
Input current
< 0.15 mA
Effect of the wire resistance (with 3-wire and 4-wire connec‐
tions)
< 0.002 Ω/Ω
Cable, wire-wire capacity
Max. 30 nF (potentiometer > 400 Ω)
Max. 50 nF (potentiometer ≤ 400 Ω)
Fault detection, programmable
None, short-circuited, broken, short-circuited or broken
Note: When the configured potentiometer size is below the constant detection limit for short-circuited inputs, the detection of
short circuits is disabled regardless of the configuration of the fault detection.
Detection limit for short-circuited input
15 Ω
Fault detection time, wiper arm (no short-circuit detection)
≤ 75 ms (typically 70 ms)
Fault detection time, element
≤ 2000 ms
Fault detection time (for 4-wire and 5-wire)
≤ 2000 ms
12.2.6.5
Voltage
Voltage input
Measuring range
-800 ... +800 mV (bipolar)
-100 ... +1700 mV
Min. measuring span
2.5 mV
Input resistance
10 MΩ
Cable, wire-wire capacity
Max. 30 nF (input range: -100 ... 1700 mV)
Max. 50 nF (input range: -20 ... 100 mV)
Error detection, programmable
None, broken
Error detection time
≤ 75 ms (typically 70 ms)
Technical data
12.2 SITRANS TH320/TH420/TR320/TR420/TF320/TF420
SITRANS TH100/TH320/TH420/TR320/TR420/TF320/TF420 with 4 to 20 mA/HART
Operating Instructions, 05/2020, A5E41864807-AB
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