Endress+Hauser Solitrend MMP40, Operating Instructions Manual

Page: 27 / 36

Solitrend MMP40 Diagnostics and troubleshooting
Hauser 27
If this is the case, the sensor can then be fine-tuned to achieve an accuracy of +/-0.1 % in
relation to the laboratory value in a variety of ways.
• Depending on the PLC, it is possible to perform a parallel shift/offset in the PLC. The
parameter has different names depending on the PLC (e.g. initial load, zero point, offset,
measuring range, etc.)
Please contact the PLC manufacturer for more information
• With the remote display, a fine adjustment or parallel shift in the sensor can be
performed using the "Offset" parameter.
If the moisture value displayed by the sensor deviates from the laboratory value by
more than +/-1 % during initial commissioning, this can be caused by the following:
• The sensor is not correctly installed under the silo discharge hatch. The surface of the
sensor must be completely covered with sand/gravel when the hatch opens. Good and
stable material flow must be ensured. A video of the batch process can be helpful for
analysis purposes.
• The wrong calibration curve is configured in the sensor. The sensor is supplied with the
universal calibration curve Cal1 for sand and gravel.
• Incorrect moisture scaling is configured in the PLC. In the sensor, 0 to 20 % moisture
corresponds to the 0 to 20 mA or 4 to 20 mA current output. The 0 to 20 % moisture
scaling must also be entered in the PLC.
Please contact the PLC manufacturer for more information.
• A 2-point calibration in the PLC or the sensor may be required for special sands (e.g. fine
sand).
• In the case of gravel and grit, limits must be set in the PLC, as running water in the
gravel or grit results in an excessively high moisture value in the sensor.
Please contact the PLC manufacturer for more information.
• Due to inaccurate data processing, it may be necessary to check the moisture value
displayed in the PLC. For this purpose, connect the sensor to the remote display and
check/compare the moisture value shown in the PLC with the moisture value shown on
the display.
Caution:
The "CH" operating mode in the sensor must then be set to the "CC" mode for a test run,
and then switched back to "CH" afterwards.
• Check the start/stop conditions in the PLC
• Start condition: time in seconds or kg in the scales
• Stop condition: usually % of target weight
• Please contact the PLC manufacturer for more information
If the solutions outlined here do not rectify the problem → contact the manufacturer's
Service Department.