6 Commissioning Promag 53 PROFIBUS-DP/-PA
106 Endress+Hauser
6.5 Empty-pipe/full-pipe calibration
Flow cannot be measured correctly unless the measuring tube is full. The Empty Pipe
Detection function (EPD = Empty Pipe Detection) allows this status to be monitored con-
tinuously.
The EPD function cannot be activated until after empty/full pipe calibration has been
performed. This adjustment procedure is described below.
Note:
• These settings can also be made in accordance with the manufacturer's specific
matrix using Commuwin II.
• The EPD function is only available if the sensor is equipped with an EPD
electrode.
• If the EPD electrode is installed, the sensor is calibrated ex-works with water, i.e. at
approximately 500
µS/cm. If the fluid conductivity differs from this reference, empty
pipe/full pipe calibration has to be performed again on site.
• The default setting for EPD when the devices are delivered is OFF; the function has to
be activated if required.
• The EPD process error is issued via the status and diagnosis messages.
Response to partially filled pipe
If EPD is on and trips in response to a partially filled or empty measuring tube, the mes-
sage “PARTIALLY FILLED PIPE” appears on the local display. The message is also
transferred in the status and diagnosis message to the control system during cyclic data
exchange
→ Page 115 ff.
If the pipe is partially filled or empty and EPD is not on, response can vary in identically
configured systems:
• Flow reading fluctuates
• Zero flow
• Excessively high flow readings
Perform empty and full pipe calibration (EPD)
1. Select the appropriate function in the function matrix:
HOME
→
→
→ BASIC FUNCTION →
→
→ PROCESS PARAMETER
→
→
→ ADJUSTMENT →
→ EPD ADJUSTMENT
2. Empty the piping. Make sure that the wall of the measuring tube is wetted with fluid
for the calibration procedure.
3. Start empty pipe calibration:
Select EMPTY PIPE ADJUSTMENT setting and confirm with
.
4. Fill the pipe with fluid.
5. Start full pipe calibration with the fluid at a standstill:
Select FULL PIPE ADJUSTMENT setting and confirm with
.
6. Switch on Empty Pipe Detection after calibration
→ Select “ON” and confirm
with
.
Caution:
The calibration coefficients must be valid before you can activate the EPD function.
If calibration is incorrect the following messages might appear on the display:
– EPD ADJUSTMENT FULL = EMPTY
The EPD calibration values for empty pipe and full pipe are identical.
– EPD ADJUSTMENT NOT OK
EPD calibration is not possible because the fluid's conductivity is out of range.
In cases of this nature you must repeat empty-pipe or full-pipe calibration!
These messages will also be displayed in the cyclic status and in the diagnosis of
the control system (error messages
→ Page 115 ff.).
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