JUMO 707020 dTRANS T02Ex - Four-Wire Transmitter Operating Manual - Handbuch (Seite 67)

23
8 Functions and operation
Teach-in
The “Teach-in” parameter serves to define the 0 % value.
During programming the zero point is produced at the output (e.g.
4mA). This value is accepted by pressing the “Zero” button (“Zero”
only, not together with “Span”). After a time-out without
acceptance, the old value will be available again.
Example:
The position of a valve is detected by a potentiometer. The
potentiometer covers the range 50 to 150
, with 50
corresponding to the valve closed. The range is programmed as
follows:
- potentiometer 50 — 150

- output 0 — 20mA
However, because of mechanical tolerances, the potentiometer
position is 52
 with the valve closed, thus resulting in an output
current of 0.4mA. Thanks to the “teach-in” function, this error can
be eliminated as follows:
- close valve
- call parameter level and select “Teach-in”
(0.4mA should then be present at the output).
- press the “Zero” button – the output
must now change to 0mA.
- confirm alteration by simultaneously
pressing the “Span” and “Zero” buttons.
- exit the parameter level (either after a time-out of 20sec, or by
pressing “Span” and “Zero” again).