6 Commissioning
TopClean S CPC 30
52
EHauser
Fig. 21: Left: pulse-width modulation (PWM)
Right: pulse-frequency modulation (PFM)
3.
Three PS ("three-point step controller")
With the Mycom S, this type of control is only possible for
one
process side (acid
or
alkali). With two-sided processes, either PWM or PFM must be used for the other
process side.
This type of actuator control is intended for actuator drives (e.g. motor-driven valves,
etc.) where a motor must be controlled directly. For this, two relays are required: one
"+relay", which, by picking-up, opens the valve and one "–relay", which closes the valve.
So that the Mycom S can set an actuating variable of, for example, 40% (valve 40%
open), it requires the input of the time that the "+relay" is picked up to completely open a
completely closed valve (= "motor run time").
!
Note!
If using a driven valve, gate valve or similar, you must determine the motor run time,
before
beginning with the menu settings.
4.
Analogue (via current output 2, 20mA)
The current output can be used to output the
analogue
actuating variable for one or two-
sided processes and
cannot
be combined with the method described above.
•
With
one-sided
processes, the actuating variable range 0 % ... 100%
(or –100 % ... 0%) is represented on the selected current range (0 ... 20 mA or
4 ... 20 mA). The output current is proportional to the actuating variable.
•
With a
two-sided
process, the complete actuating variable range from
–100% ... +100% is represented on the given current range. An actuating variable of
0% leads to a current of 10 mA (at 0 ... 20 mA) or 12 mA (at 4 .. 20 mA), (see fig. 22).
!
Note!
With a two-sided process, it should be noted that the actuator uses this method (also
known as "split range").
Fig. 22: A: Stroke diagram for a control valve
B: Stroke diagram for two contrarotating control valves ("split range")
on
on
off
off
t
ON
t
ON
t
OFF
period T
time [s]
time [s]
contact
contact
C07-CPM153xx-05-06-00-en-004.EPS
A
B
mA
mA
4
8
12
16
20
4
8
12
16
20
50
100
0
50
100
0
C07-CPM153xx-05-06-xx-en-001
Stroke
[%]
Stroke
[%]
Содержание TopClean S CPC 30
Страница 127: ...TopClean S CPC 30 11 Appendix Endress Hauser 127...
Страница 138: ...11 Appendix TopClean S CPC 30 138 Endress Hauser...
Страница 144: ...12 Index TopClean S CPC 30 144 Endress Hauser...
