GPC, PPU
Option O1, Water turbine control
DEIF A/S
Page 15 of 19
There can be up to 4 analogue outputs for cascade control of valves.
Analogue control, stand-alone generator with load control
If the generator is a stand-alone (typical for micro synchronous water turbines), the RPM is often
controlled with variable loads (thyristor controlled resistive loads).
In this case, the analogue outputs can be inverted so that the analogue output will decrease in
case an increased RPM is needed. In this case, the output curves look like this:
There can be up to 4 analogue outputs for cascade control of loads.
Sequences
Turbine start
Due to the slow start-up of a turbine, the function in menu 2255 ‘Turbine start timer’ has been
added. The turbine start function can be used in connection with relay outputs only.
This timer represents the time where the speed UP signal is active if no speed is detected during
start-up of the turbine. (Running detection is the frequency measurement or pick-up tacho input).
20 mA
Power/speed
demand
Output
Cascade #1
Cascade #2
Cascade #3
Cascade #4
0 mA
20 mA
Speed
demand
Output
Cascade #1
Cascade #2
Cascade #3
Cascade #4
0 mA
