converting 0-10v analogue output

[Dino]

Can anyone tell me if it is possible to convert the 0-10v analogue output to some form of pulsed output and how do i do it. What i am trying to do is use a pid so as i get nearer my setpoint the pulses get more rapid to stabilize the setpoint, if it goes above the setpoint it would need to stop and at start it would have to be on almost permantly and then start to pulse as it reaches the designated setpoint.

[Maikky]

Dear Dino.

Did you check the link I mentioned in your earlier thread.

The file PI-Regler mit PWM.e60 is exactly what you need.

In case you need an English translation it would be no big problem.

Regards
Maikky

[srd]

Yeah cheers for that Maikky i think i sort of got it but english translated might help me a bit more, also sorry to sound a bit thick but if i put it on the simulator Q1 does'nt seem to do anyting on the front screen.

[Maikky]

Dear srd.

I will make a translation today.

Regards
Maikky

 

[Maikky]

@all

Attached please find translated versions of temperature control programs originally
published by knodelpa.

http://easy-forum.net/index.php?topic=2132.msg9548#msg9548



PI-control with analogue outout

As reference an example with analogue output is attached. In most cases the differential
part of PID is not used for temperature control.

The function block for PID-control (DC-block) is using a 12 bit output (0 to 4095) but the
analogue output QA1 is limited to 10 bits (0 to 1023). Therefore a recalculation is required
to transfer the DC output to QA1.


PI-control with PWM output

Instead of an analogue output a pulsed digital one may be used. The MFD is equipped with
two function blocks PW for pulse witdh modulation.

Caused by the switching frequency it is recommended to use the transistor output type
(MFD-Txx) together with solid state contactors instead of the relay output type (MFD-Rxx).

The PW – blocks are directly hardware related to outputs Q1 for PW1 and Q2 for PW2.
Therefore it is not possible to simulate the outputs within EasySoft.

At this example PW1 (equalling output Q1) is used.


3 point stepping control

In case two independent outputs are required – for example one valve to open and one
valve to close – a 3 point stepping control may be used.

The main difference compared to a PI-control with one output is, that only the proportional
part of DC-function block is used and that the operating mode is bipolar from -4096 to +4096.

- actual temperature = set-point temperature  : both outputs off
- actual temperature < set-point temperature  : "valve to open" is pulsing
- actual temperature > set-point temperature  : "valve to close" is pulsing

Caused by the fact, that the PW-blocks are using positive values as input, the negative
values of control output have to be inverted for PW2.

As already mentioned above the PW – blocks are directly hardware related to outputs Q1
for PW1 and Q2 for PW2. Therefore it is not possible to simulate the outputs within
EasySoft.

Hopefully my translation is correct and helpful.

Regards
Maikky

[srd]

Thanks very much for that Maikky you've been a great help.

[Luis Peres]

@all

Attached please find translated versions of temperature control programs originally
published by knodelpa.

http://easy-forum.net/index.php?topic=2132.msg9548#msg9548



PI-control with analogue outout

As reference an example with analogue output is attached. In most cases the differential
part of PID is not used for temperature control.

The function block for PID-control (DC-block) is using a 12 bit output (0 to 4095) but the
analogue output QA1 is limited to 10 bits (0 to 1023). Therefore a recalculation is required
to transfer the DC output to QA1.


PI-control with PWM output

Instead of an analogue output a pulsed digital one may be used. The MFD is equipped with
two function blocks PW for pulse witdh modulation.

Caused by the switching frequency it is recommended to use the transistor output type
(MFD-Txx) together with solid state contactors instead of the relay output type (MFD-Rxx).

The PW – blocks are directly hardware related to outputs Q1 for PW1 and Q2 for PW2.
Therefore it is not possible to simulate the outputs within EasySoft.

At this example PW1 (equalling output Q1) is used.


3 point stepping control

In case two independent outputs are required – for example one valve to open and one
valve to close – a 3 point stepping control may be used.

The main difference compared to a PI-control with one output is, that only the proportional
part of DC-function block is used and that the operating mode is bipolar from -4096 to +4096.

- actual temperature = set-point temperature  : both outputs off
- actual temperature < set-point temperature  : "valve to open" is pulsing
- actual temperature > set-point temperature  : "valve to close" is pulsing

Caused by the fact, that the PW-blocks are using positive values as input, the negative
values of control output have to be inverted for PW2.

As already mentioned above the PW – blocks are directly hardware related to outputs Q1
for PW1 and Q2 for PW2. Therefore it is not possible to simulate the outputs within
EasySoft.

Hopefully my translation is correct and helpful.

Regards
Maikky

How can we define inverse and direct controller PID for analog output.
As I see the PID work with inverse control. How can we make the direct control for the 0-10V output?
Regards

[Maikky]

Dear Luis Peres.

I am not fully sure whether I understood your question, but I assume what you want to know
and try to answer it.

The parameters I1 and I2 at the DC-function block are used as
   I1 : set value          (for example MW50)
   I2 : actual value      (for example MW51)
The controller is increasing the output if I1 is larger than I2.

To reverse this behaviour you simply exchange the values. With the above mentioned example
and designating I1 to MW51 and I2 to MW50 the output decreases.

Regards
Maikky