JUMO 709061 TYA 201 - Single-Phase Power Controller Operating Manual - Manual (Page 87)

2012-12-01/00561071 [SCR Power Controller TYA201] 85
6 Special device functions
Alternatively, the SCR output can also be switched off via the PROFIBUS,
RS422/485 interfaces.
6.11 SCR control logic (switch)
Operating mode If the power controller is set to
r
SCR control
r
Logic (switch), the power con-
troller operates as an electronic switch.
For as long as the configured binary or analog input is closed, the SCRs are
fired in zero crossing of the supply voltage and are only locked once again
when the binary or analog input is opened.
Transformer
loads In the case of transformer loads, the first supply voltage half-wave of each
pulse group must be cut. This can be done by configuring
α
start and entering
a value.
v Chapter 5.1.2 "Power controller"
The phase control angle for each first half-wave can be selected between 0
and 90 °.
α
input The full power is switched by closing the binary input. If this is too high for the
case at hand (e.g. in the case of quick heat-up processes), the output power
can be reduced
by cutting all sine wave cycles (
α
input).
v Chapter 5.1.4 "Setpoint value configuration"
Time behavior If only short pulse packages with a defined number of sine wave cycles should
be switched, the binary input (control direction "Open inactive") must be con-
trolled via an optocoupler and the following timing must be observed:
Example for
supply frequen-
cy
of 50 Hz
The power controller requires an internal processing time and does not switch
until the next zero crossing occurs. This results in delay time of 25 to 60 ms
(see arrows) between the binary signal and the switching operation of the sine
wave cycle.
Formula (50 Hz) Binary signal length for n sine wave cycles = (n
 20 ms) ±
5 ms
If the binary signal is, for example, 48 ms long and therefore calculated longer
than for two sine wave cycles, it may be the case that the power controller
switches two or even three sine wave cycles.
Formula (60 Hz) Binary signal length for n sine wave cycles = (n
 16.6 ms) ±
5 ms