SITRANS LR250 (PROFIBUS PA)
Operating Instructions, 08/2014, A5E32221386-AC
171
Diagnosing and troubleshooting
10
10.1
Communication troubleshooting
1.
Check the following:
–
There is power at the device.
–
The LCD shows the relevant data.
–
The device can be programmed using the handheld programmer.
–
If any fault codes are being displayed see Acyclic Extended Diagnostics (General Fault
Codes) (Page 275) for a detailed list.
2.
Verify that the wiring connections are correct.
3.
Check the PROFIBUS address and make sure all devices are at unique PROFIBUS
addresses.
4.
See the table below for specific symptoms.
Symptom
Corrective action
The device cannot be programmed via the
handheld programmer.
•
Make sure Write Protection (6.2.1.) is set to the
unlock value.
You try to set a SITRANS LR250
parameter via remote communications but
the parameter remains unchanged.
•
Ensure Remote Lockout (6.1.1.) is disabled.
•
Ensure Write Protection (6.2.1.) is set to the unlock
value.
•
See Resetting the PROFIBUS address to 126
(Page 96) to disable an address lock.
The PLC value equals the display value
but does not correspond to actual material
level.
•
Ensure Scaling in AIFB1 is correctly entered.
•
Ensure High Calibration Point is correctly entered.
•
View the echo profile to see if the wrong echo is
being selected. If so, see Operation Troubleshooting
(Page 176) for possible causes and corrective action.
The PLC value is not equal to the
displayed value (regardless of actual
material level).
•
Confirm you are looking at the right spot in the PLC.
•
Ensure scaling has not been programmed into the
PLC: all scaling should be performed by the LR250.
•
Check the network to ensure the PLC is
communicating with the LR250.
If you continue to experience problems go to our website and check the FAQs for SITRANS
LR250:
Product page (
), or contact your Siemens representative.