The controller only controls
‘one-way’
.
Only one position or one negative control
variable can be calculated. The direction
of the control variable is set in the
‘PUMP’
menu. There is no dead zone. In this
sense, the control cannot be
‘deactivated’
(except with
‘STOP’
or
‘PAUSE’
).
The value of the P-proportion of the con‐
trol (Xp) is specified for the controller in
the unit of the corresponding measured
variable.
With pure P-control and a difference
between the set and actual values, which
corresponds to the Xp value, the calcu‐
lated control variable is +100% (at the
‘raise’
setting) and -100% (at the
‘lower’
setting).
7.3 Selecting the sensor type
Input of the cable length and the
cross-sectional area
The precise entry of the cable length
is important with longer cable lengths.
With a conductivity value of e.g.
10mS (corresponding to 100 ohms),
the displayed value changes by 1%
every 10 m of cable length.
The Pt100 measurement is corrected
by the cable resistance that comes
from the cable length entered. The
correction for a cable with a cross-
sectional area of 0.25 mm
2
is 3.5 °C
every 10 m of cable length.
ProMinent sensor cable, see
Ä Table on page 101and the fixed-
cable sensors are 0.25 mm
2
.
Adjustable parameters in the [INPUT]
> [CABLE] menu
–
0.14 mm
2
–
0.25mm
2
(default value)
–
0.34 mm
2
–
0.50 mm
2
Commissioning
44
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