Endress+Hauser PROMAG 33 - Page 75

Function group
PROCESSING PARAMETERS
MEASURING
MODE
With this function the flow direction for measurement is specified for the signal
output:
•
Unidirectional:
Signal output in the positive direction only (forward).
Flows in a negative direction (backwards) are not included or totalised
by the Promag measuring system.
•
Bidirectional:
Signal output in both directions (forward and reverse).
Note!
The flow display always operates in both flow directions independent of the
setting in this function.
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UNIDIRECTIONAL – BIDIRECTIONAL
FLOW
DIRECTION
In special cases it is possible that the arrow marked on the sensor nameplate
does not agree with the actual flow direction of the fluid (Example: the sensor is
operated “upside down”). In this function you have the option to change the
arithmetical sign of the flow variable.
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FORWARD * – REVERSE **
* Positive flow according to the arrow on the nameplate.
** Positive flow in the opposite direction to the arrow on the nameplate.
FUNCTION ECC
Switching on and off the Electrode Cleaning Circuitry (ECC).
Note!
• This function is only available if the Promag 33 is fitted with an electrode
cleaning function (optional).
• The ECC function is not available with the remote “FL” version.
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ON ECC switched on
OFF ECC switched off
Remarks on ECC:
Conductive build-up on the electrodes and the measuring tube walls (e.g.
magnetite) can cause measurement errors. The ECC has been developed in
order to prevent build-up occurring. The cleaning cycle of 3 seconds is
dependent on the tracking frequency and repeats itself every 30 minutes.
The ECC works in the way described for all electrode materials available
except tantalum. If the electrode material is tantalum then the ECC only
protects the electrode surface from oxidation.
Caution!
If the ECC is switched off for a long period of time in an application where there
is a conductive build-up in the measuring tube, then this can lead to errors.
If there is a large concentration of build-up at one point, then, under certain
circumstances, switching on the ECC may not remove it. In such cases the
flowmeter is to be cleaned and the build-up removed.
Note!
Note!
Caution!
Promag 33 6 Description of Functions
Endress+Hauser 75