8
2.6
Setting the heating current monitoring
Select “
Overcurrent
” in the engineering menu, then press the
<Set>
key.
In the upcoming modification dialogue you determine whether the current monitoring shall take place
with a fixed (Fixed) or a floating over current threshold (Float).
Factory setting:
Float
Setting range:
Float
(floating over current threshold) or
Fixed
(fixed over current threshold)
Notes on settings
For the heating current monitoring, there are two over current thresholds:
– The threshold for the
excess current
is set to 135% of the maximum nominal current (
violet
, narrow
dashed line in the following diagram). This threshold value is fixed and leads always to a draining
of the cylinder and to an emergency shut-down (Error E25) when exceeded.
– The threshold for the
over current
is set to 125% of the maximum nominal current (W24/E24). If
this threshold value is exceeded the unit tries to reduce the current under 125 % by repetitive drain-
ings. If after 5 repetitive drainings the current value is still above the threshold value of 125 % the
unit goes on error (Error 24).
This threshold is fixed based on the maximum nominal current if
Fixed
is selected (
light blue
, con-
tinuous line in the following diagram).
With the function
Float
the over current threshold (
red
, dash-dotted line in the following diagram)
can be flattened. The function Float allows a faster reaction to changes of the control signal.
Overcurrent
Fixed
Float
Float
Esc
Set
Engineering
GFCI :Set
Overcurrent :Float
Min.Request :25/20%
Drain Cool :On
Stop Mode :Set
Esc
Set
Example:
Nominal current at 100% steam pro-
duction with 400V 10kg/h = 10 A
Actual steam demand 30%
––> Current setpoint value = 3 A
Draining as a result of over current at
4.5 A with setting “float”
Draining as a result of over current at
12.5 A with setting “Fixed”
20 25
30 35
40
45
50
55
60
65
70
75
80
85
90
95 100
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
Draining characteristics with over current
Nominal current 100%
Current setpoint value
Draining if current value exceeds the set point value by a factor of 1.5 (setting “Float”)
Draining if current value reaches 125 % of the maximum nominal current value (setting “Fixed”)
Forced draining if current value reaches 135 % of maximum nominal current value
Current value in %
Steam production demand in %
