User’s & Technical Manual –
LEVEL TRANSMITTER LTR7000
GELEC
Industrial Electronics
PAGE
16
PLACEMENT ON THE MEASURING CHAMBER
The LTR7000 tube contains the hall effect sensor chain and has to be tangent to the
measuring chamber, in order to be as close as possible to the magnetic float. On the back
of the tube, at the side that faces the measuring chamber, there are two engraved lines that
define the
active measuring segment
(check the relevant section for more details).
In a common installation, the LTR700 is installed with the bottom engraved line at the point
where the magnetic float stands in an empty tank. Notice that this point is not the bottom
of the measuring chamber, but the position of the
float’s incorporated
magnet.
It may be difficult to specify the exact position of the magnetic float inside the measuring
chamber. In order to find this point and make sure that the magnet will always move within
the LTR7000 measuring segment during process stages, follow the below procedure.
▪
Empty the tank, so the magnetic float drops at the lowest possible position
inside the measuring chamber.
▪
Having the dip-switch SW4 to ON position and the LTR7000 far from the
measuring chamber and the magnetic float, monitor its output with a
multimeter. At this point, the output provides an error value (24mA), because
the magnet is uncoupled from the sensors.
▪
Place the LTR7000 on the measuring chamber in a high position and slowly start
sliding it towards the magnetic float, while checking the multimeter. When the
bottom engraved line reaches the float
’s magnet
, the LTR7000 output will
change to the minimum value of the selected output range (4mA or 0mA),
because the magnet triggers the first sensor of the active measuring segment.
Continue sliding the LTR7000 1cm more, to safely pass this critical point.
✓
Mark this position for the LTR7000 final mounting. This position allows you to
exploit the whole active measuring segment of your version. Re-calibrate Low
Level after the final mounting, in order to precisely get the minimum output of
the selected output range when the tank is empty.
