\\Elmacron-server\Gemensam\Instruktioner\Instruktioner i W ord\1005RE\Engelska\1005RE-ORP%E.doc
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Senast utskrivet 2007-10-11
11:16
4.3 PWM ( pulse width modulated ) REGULATION
At pulse width modulated regulation the relay outputs "on"-time is decided by the distance between the
limit value and the actual value, the chosen proportional band and the chosen period time.
Example at pulse width modulated regulation.
Parameters:
Limit value 1
20
%
, high
Xp-band 25
%
Period time, T
100 seconds
The proportional band ( the XP-band ) is given in % of full measure range.
Measure range = 0 - 100
%
= 100
%
-units, which gives Xp-band 25% of 100
%
-units = 25
%
-units in
our example.
Relay "on" ( % of period time ) is
given as a linear function
between 20
%
and 45
%
, where
the "on"-time is 0% of the period
time at 20
%
and 100% of the
period time at 45
%
and above.
NOTE ! t
min
= 500 ms, t
max
= T minus 230 ms
%
100%
50%
10
20
30
40
50
60
Proportional band
limit value 1
Relay “on”
in % of period time
T
t
on
off
T = Period time
t = Actual % av Period time
