5
4.2
Open Channel Flow Measurement
•
For ultimate accuracy, install the sensor as close as possible above the expected maximum water level (see minimum measuring
range).
•
Install the device upstream in a place defined by the characteristics of overflow and metering channel along the longitudinal axis of
the flume or weir.
•
From the point of view of measurement accuracy the length of the channel sections preceding and following the measuring flume
and their method of joining to the measuring channel section are of critical importance.
•
Despite of the most careful installation, the accuracy of flow metering will be lower than that of specified for distance
measurement. It will be determined by the features of the flume or weir applied.
4.3
Electrical Connection
•
Screw out the hexagonal countersunk screw at the side
of the model. Lift the tilt cover to access the screw
terminal.
•
There is a basic requirement for separating the 4...20
mA signal cable and 230 V AC supply
(or output relay) cable by shielding.
•
For grounding the unit, either use the grounding screw
terminal on the outside of the housing; or use a three
wire mains cable, connecting the third wire to the
internal grounding screw terminal.
•
Three-wire installation is also possible for the 24 V
DC versions by connecting the terminals 1 and 6.
In
this case the galvanic isolation is not provided.
•
The unit may be damaged by electrostatic discharge
(EDS), via terminal, thus apply the precautions
commonly used to avoid electrostatic discharge.
5. PROGRAMMING
The Echotel will be delivered with the following Factory Default:
⇒
Current output, display and bargraph: LEVEL
⇒
4 mA: assigned to the minimum level 0%
⇒
20 mA: assigned to the maximum level 100%
⇒
Error indication by the current output: hold last value
⇒
Damping: 60 sec for liquids, 300 sec for solids
The device can be programmed in two ways:
•
Touch-Magnet Programming
by the supplied magnetic screwdriver (with level transmitters for liquids only), see 5.1.
Assignment of the levels to the 4 and 20 mA current output, relay switch differential (both with an accuracy of
±
20 mm) error
indication by the analogue signal and damping can be set.
•
With the
046-8108-001 programming module
, see 5.2.
All features of the device can be set, such as measurement configuration and optimization, relay programming, 32-point
linearisation, dimensions
for 6 tanks with different shape and for 21 different open channels (flume or weir) etc.
Some Devices are already equipped with the 046-8108-001 (see Identification code – page 3).
The Echotel is fully operational without the 046-8108-001. The 046-8108-001 is only needed for programming and/or displaying
measurement values.
If the transmitter is left in Programming Mode by mistake, it will automatically return to Measurement Mode after 30 minutes and will
operate with the parameters entered during the last completed programming.