11.3
Troubleshooting
Symptom
Cause of error
Remedy
Display empty or
shows "INIT", no
transmission pul‐
ses
No or incorrect supply voltage
Check the voltage at the terminals, the connections and
the wiring.
Display shows
"#####" instead
of the current
measured value
Value too large to appear on the display
Adjust the unit so that a lower value can be displayed.
11.4
Troubleshooting of USB modem
Below you can find information on how to troubleshoot simple errors yourself.
LED on the USB modem
Cause of error
Remedy
Power LED is not lit.
The USB cable is not connected.
• Connect the USB cable.
Connecting USB modem (Page 131)
Hardware fault occurred.
• Replace the device.
Power LED flashes yellow
during parameter assign‐
ment of the temperature
transmitter.
No temperature transmitter connected.
1. Check the polarity on the temperature transmit‐
ter.
Connecting USB modem (Page 131)
2. Check whether the loop current is at least
3.5 mA.
Comm LED is not lit.
USB modem is not detected by the PC.
1. Check the port settings in SIPROM T.
2. Check the driver installation and reinstall SI‐
PROM T if necessary.
Error LED illuminates red
during the temperature
transmitter parameter as‐
signment.
Short-circuit at the modem terminals for
the temperature transmitter.
• Check the wiring of the modem terminals.
Connecting USB modem (Page 131)
Error LED is lit red.
Hardware fault occurred.
• If the Error LED remains continuously lit even af‐
ter repeatedly switching the power supply of the
modem off and on, the USB modem is defective.
Replace the USB module.
See also
Meaning of LEDs on the USB modem (Page 59)
Diagnostics and troubleshooting
11.4 Troubleshooting of USB modem
SITRANS TH100/TH320/TH420/TR320/TR420/TF320/TF420 with 4 to 20 mA/HART
192
Operating Instructions, 05/2020, A5E41864807-AB