Endress+Hauser PROMAG 33, Operating Manual

Page: 73 / 126

Function group
PROCESSING PARAMETERS
EMPTY PIPE
DET.
With this function (EPD = Empty Pipe Detection), two procedures can always
be activated:
– Carrying out the empty and full pipe adjustment (
before switching on EPD!).
– Switching on/off Empty Pipe Detection.
Note!
•
This function is only available if the sensor is fitted with an extra
EPD electrode.
•
The EPD function is not available with the remote “FL” version.
•
The connection cable with the remote “FS” version may only be a
maximum of 10 m long. Only then can correct functioning of the EPD
be guaranteed!
•
The EPD function is switched off when the flowmeter is delivered and
must be switched on manually when required.
•
EPD has the same effect on the outputs as if there was a fault.
A corresponding alarm message can be indicated via both relay outputs
(1 or 2) if configured accordingly.
6
OFF EPD switched off
ON EPD switched on
EMPTY PIPE ADJ. Start empty pipe adjustment (confirm with
1
)
FULL PIPE ADJUST Start full pipe adjustment (confirm with
1
)
Remarks on Empty Pipe Detection (EPD)
Only a completely full measuring tube enables correct readings to be
obtained. This can be continuously checked by Empty Pipe Detection.
EPD is based on measuring the impedance between reference and EPD
electrode (see Figure).
Response when partially full
If the EPD is active and responds due to a partially filled or empty pipe, then
the alarm message “A: EMPTY PIPE DETECTED” is shown on the display.
The outputs respond in such cases as described on page 85.
When the pipe is partially filled and the EPD is not activated, then the response
may be different for identical plants:
– varying flow display
– zero flow
– excess flow values
(continued on next page)
Empty pipe
Value 1
Switch point
EPD
Value 2
1/2
×
(value 1 + 2)
Impedance
[
Ω
]
Full pipe
ba009
y
3
9
Internal measured
value
Note!
Promag 33 6 Description of Functions
Hauser 73