Endress+Hauser Proline Promag 55, Operating Manual

Page: 46 / 130

7 Block BASIC FUNCTION Device Functions Proline Promag 55 FOUNDATION Fieldbus
46 Hauser
7.2.2 Function group EPD PARAMETER
BASIC FUNCTION G
⇒
FOUNDATION FIELDBUS GGA
⇓
PROCESS PARAMETER GIA
⇒
CONFIGURATION 640
⇓
EPD PARAMETER 642
Function description
BASIC FUNCTION
→
PROCESS PARAMETER
→
EPD PARAMETER
EMPTY PIPE DET.
(6420) Flow cannot be measured correctly unless the measuring tube is completely full. This
status can be monitored at all times with the Empty Pipe Detection function. To do this,
the empty pipe detection (EPD, empty pipe detection by means of EPD electrode) can be
activated in this function:
Options:
OFF
ON STANDARD
Factory setting:
OFF
!
Note!
• The option ON STANDARD is not available unless the sensor is equipped with an EPD
electrode.
• The default setting for the EPD function when the device is delivered is OFF. The
function must be activated as required.
• The devices are already calibrated at the factory with water (approx. 500
µ
S/cm).
If the conductivity of certain fluids deviates from this reference, empty pipe/full pipe
adjustment must be performed again on site (see Function EPD ADJUSTMENT (6481)
on page 48).
• The adjustment coefficients must be valid before you can switch on the EPD function.
If these coefficients are not available, the function EPD ADJUSTMENT (see Page 48)
is displayed.
• If there are problems with the adjustment, the following error messages appear on the
screen:
– ADJUSTMENT FULL = EMPTY:
The adjustment values for empty pipe and full pipe are identical. In such instances,
empty pipe adjustment/full pipe adjustment
must be carried out again .
– ADJUSTMENT NOT OK:
Adjustment is not possible as the fluid conductivity values are outside the permitted
range.
Notes on empty pipe detection (EPD)
• Flow cannot be measured correctly unless the measuring tube is completely full. This
status can be monitored at all times with the EPD function.
• An empty or partially filled pipe is a process error. A default factory setting defines that
a notice message is issued and that this process error has no effect on the outputs.
• A plausibility check of the adjustment values will only be executed by activating the
empty pipe detection. If an empty or full pipe adjustment is performed when empty
pipe detection is active, the empty pipe detection has to be deactivated and activated
again after finishing the adjustment in order to start the plausibility check.
Response to partially filled pipes
If the EPD is switched on and responds to a partially filled or empty pipe, the notice
message "EMPTY PIPE" appears on the display. If the pipe is partially empty and the EPD
is
not switched on, the response can vary in identically configured systems:
• Flow reading fluctuates
• Zero flow
• Excessively high flow values