control program for pneumatic valve with PID error

[komal.sukre]

I don,t know how to design a ladder to control operation of pneumatic valve with PID input?

 

[arkyny]

:site: And?

 

[SHKODRAN]

It is not clear what you are looking for ..
More details please, we are not in your brain.

 

[komal.sukre]

its like----

for a recipe i need to control tempreture profile as
for first 10 min 10 degree rise
keep it constant for next 20 min
for further 5 min rise temperature by 10 degrees

but this temperature profile may be different for different recipes

so need to control the pneumatic valve according PID status?
how can i do this?

 

[SHKODRAN]

If I understand it, you have to check the temperature with a modulating valve?
What kind of CPU you want to use?
The modulating valve is of the type actuator or positioner?
The diameter of the steam pipe?
The amount of the product to be heated?
Type of product to heat, viscous or liquid...etc!

 

[komal.sukre]

---

initially room temperature will b noted for the mixture in reactor.
according to that set a set point to ramp the temp by 10 degree rise in 10 minutes.
if temperature exceeds 10 degrees close the valve completely.


the problem doesn't mentioned the type of liquid, diameter of pipe, amount of liquid... and other you have asked.

n about amount it will be total of all 8 tanks contains passed in specified amount.

for example for recipe A tank1 pass 10 liters, tank2 5 liters, tank3 25 liters....... tank8 15 liters etc.

 

[komal.sukre]

Here I made a try to develop a ramp assuming
My initial temperature is ( or TT has sensed temp as ) let say 7. Firstly brought it at 10. Then keep it constant for 10minutes. Then raised it by 5 degrees in 5 minutes.
The temperature sensed by TT is moved in soft tag TT for logic.
The beginning value that is 10 is moved to soft tag X.
The end value That is 15(7+3+5=15) is moved to tag Y.
X and Y are to be entered by processor through scada screen(not written the logig for accepting the values).
Logic has developed considering values are accepted.


But my problem is that, respective timers Done bits are initializing another timers. But as it is giving pulse, compute FBD does not get sufficient time to calculate values. And values are not seen in it.