[Duty cycle and frequency]

If you are using the PWM function block with an output then you should not be setting up that ouput in the hardware config as an HSO. The PWM block is meant to modulate a single ouput on and off at the selected cycle time and duty.

If you want the hardware HSO to be cotnrolled by your PID output then all you need to do is link your PID output to your HSO "duty cycle" operand and just select an appropriate frequency.

The problem is to set the appropriate frequency!

We are trying to control a hydro-turbine that runs on 50-60 Hz, we use a heater tube elements connected to the SSR and the OPLC PID-fb to controle the speed of the turbine to generate max power all the time. when we use the power for other things the PID controler loads the heater tube less to ceep up the speed that is set 55HZ .

The question is! The frequency to the to the elements ( power side of the SSR ) changes from 50-60Hz will that affect the set frequency i seleted on the controler ?

[In need of more speed ?]

Hi Joe, only issue I see with your concerns about screw dimensions is that he increased the speed by simply doubling the number of screws used. Thus, at the same rotation speed and all other things being equal it should have picked up the 8 screws just as well as it should have picked up the 4 screws from an individual timing standpoint. If I understand him correctly he didn't change the RPMs, just the number of screws per rev.

Hjalli, where are you reading the input? Are you looking at the raw value or scaled value?

When you say it "stops counting" are you saying it pegs at 230 or drops to 0?

It looks like i was to quick to post this, i only needend to posission the counter slightly better than til all worked.

Do you know a easy way to exclude the D-factor on the PID-controler with autotune?

I know for a fact that in speed control systems like runing a govinor on a diselengine the PI - control is only used.

Joe : i will post a pic soon

Damien : im looking at the raw value and it rises about 15 % when a hevy lode is lifted from spining drillhead, the dutycycle is running constant aprox 20 % then i implement load on the drillhead, then the pid-controler reacts and prolongs the dutycycele up to 100% to keep the speed upp. This works until a release the load from 100% to 20% then the speed will rise 15% over the set value.

regards Hjalli

[In need of more speed ?]

Hello

I have been testing this program using a drill with 4 screws per cycel and the drill runs at 50 rounds per sec. With the 4 screws the high speed pikup counts 200 per sec!

I have tried to have 8 screws but the high speed counter ( IM18-08NPS-ZUK from SICK, Ia = 300mA,DC 10-30V, fMax = 1000 Hz ) Stopps counting at a speed of 230 counts per sec. Some how i think we have reached the limitation of the v350-35-T2 oplc and it is not the high speed conter thats is the problem.

I feel that the pid controler is not reacting fast enough to the changes i implement.

Any ideas or some tips on the ladder ?

Kind regards

Hjalli Sig

PIDcontroler-ver1.vlp

[Duty cycle and frequency]

Hello

V 350-35-T2

Im configuring the highspeed output PWM. The Duty cycle i understand, from 0 to 1000 or 0-100% but i dont understand why i need to input the frequency ( is the frequency not constantly changing regarding the speed im trying to maintain!

[V350-35-T2 as a PI-control on a pelton hydro turbine]

hello

My gool is to control a Pelton Hydro-turbine with a load-bank. 4500W ( 4,5KW )

The equipment i have is a Unitronics V 350-35-T2 , highspeed counter and a SSR operating on 4-32VDC ( opens on zero )

The plan is to count the revs on the hydro-turbine 16 counts per rev. The operating rev should be 25 reves per sec and there for 400 counts per sec this is then feed in to the HSI ( high speed input ) on the V350 OPLC.

If the speed is growing then more load is implemented to the load bank and if the speed is dropping the load is reduced.

I have been trying to use the FB ( function block) PID with auto tune with limited results! Some how i belive i need to have the FB PWM scan also. The output from the PID is then feed in to the PWM scan, the output from the PWM is then used to determine the time of the pulse ( duty cycel )

If anyone can help with a sulution to this problem, it would be much appreciated.

Kind Regards

Hjalli