M a student n need a help to develop a chemical plant as mentioned----

komal.sukre

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Join Date
Sep 2012
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Pune
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P&ID is attached alongwith.
I need to manufacture suppose wine of different types (type A, type B…etc).
There are 8 ingredient tanks.
For each type values of ingredient interred by processor.
Start pump and transfer contains to reactor within 10 minutes.
In reactor maintain temperature profile as---
1) Rise temp by10 deg in first 10 min
2) Keep it constant for another 20 min
3) Rise 10 deg further in 5 minutes
4) Do a lab test if result is positive heat the mixture for 5 minutes to rise temp by 5 degrees.

Whole process is automatic.

Picture 007.jpg
 

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What PLC does it need to be developed on?
How far have you got with this so far?
Have you got some code that you have already written?
What is your specific problem that you are trying to overcome or is it the whole thing??
 
allen bradley 5560 is the PLC.
i just know there is need to use ramping temp concept to
maintain temperature but dont know how.
to regulate the transfer in 10minutes, the flow rate
should be fast at start and gradualy decrease for precise
flow.(just like in petrol pump).
dont have any code in written.
transfer in 10 min and temperature ramping is the main problem.
 
Sorry, I have no idea with AB stuff. I do know though that you'll get far better responses from this forum if you have a go at the problem yourself and then post back with some attempt at it and more details on where you are stuck. Good luck with it ;-)
 
Allen Bradley 5560 is the PLC.
Komal,
Sorry, but I can't figure out exactly which one you are using. Could it be Allen Bradley ControLogix 5500 software?

Or maybe you are describing the old Allen Bradley PLC5/60?
I just know there is need to use ramping temp concept to maintain temperature, but don't know how.


Here is one way to set up a temperature ramp in the Allen Bradley RSLogix 500 software. The PLC5/60 RSLogix 5 software would be very similar.
 
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Give it a go by yourself first, THEN come back and ask specific questions. We will not do your homework for you.
 
I tried to mov 10 liters with frequency of 50hz (full/fast speed) from tank1. If it is ok similar logic will apply to another 7 tanks varying value of contains that to be transfer.

Plz suggest me corrections.

But I stuck at logic of speed control at rate of 90-10.
Means 9 liters iwant to transfer at the rate of(speed of) 50 hz and for remaining 1liter want to transfer the fluid at the rate gradually decreasing from 50hx to 0hz in 10 minutes.
Plz give me hint?
 
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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.
 
My initial temperature is ( or TT has sensed temp as ) let say 7...Then raised it by 5 degrees in 5 minutes.
I think this is a mistake. You cannot successfully use "sensed temperature" as the input to your ramp. You must use the Temperature Setpoint in your ramp. The Temperature Setpoint is the input to a PID or similar control function that then determines the Control Variable output that should produce the desired "sensed temperature" (Process Variable).

The sensed temperature is a feedback to verify that your ramp is working. The sensed temperature is NOT the temperature that your ramp should use.

In other words, you are not ramping the final sensed temperature but the thermostat or temperature setting that controls the sensed temperature.

Think of it like a thermostat that controls reactor temperature. If you want to ramp the reactor temperature from "10" to "15" in 5 minutes, then that is 300/5 or 60 seconds per degree, so you fix your "thermostat" so that your PLC can start with the beginning sensed temperature, then add 1 degree to the THERMOSTAT SETTING each minute for 5 minutes. Then if your temperature controller is working correctly, when it gets the new thermostat temperature setting, it will turn on heat to raise the reactor temperture by 1 degree each minute.

To raise reactor temperature 5 degrees in 5 minutes:
1. Read reactor temperature, RT.
2. Make Reactor Setpoint Temperature RST = RT + 1 degree
3. Start timer, wait 60 seconds, then make RST = old RST + 1 degree.
4. Repeat Step 3 until Timer = 300 seconds.
5. Stop Ramp function, leaving Reactor Setpoint Temperature 5 degrees higher.

The actual Reactor Temperature RT is only used by the ramp in Step 1. After 5 minutes, RT may not be exactly 5 degrees higher, depending on the PID settings for your reactor temperature controller.
 
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---

Here is attempt to transfer the containts of tank1.
by controlling the speed of motor using VFD.
for first 80 % VFD run at full speed(100).
then it gradually decrease to zero.



rmpulse-remaining pulses


now i should haveto do this transfer in 10 minutes?
how can i?
 
Now I should have to do this transfer in 10 minutes? How can i?
I cannot read your picture attachment, so do not really know what you have done.

However, in general, to transfer a Volume V of liquid (liters or gallons) in a given time T minutes, divide V/T to find the pumping Rate in Liters per minute or Gallons per minute. Then you must set your pump speed to pump that rate of liquid for T minutes.

Of course to make any pump do what you want, you really need to know the pump specifications - a pump curve to show how much it can pump at any given speed.
 
-----code

is this code image of transfer with VFD control visible?

m still not get how to limit transfer within 10 minutes.
 

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