Hi, Experts please i wish to do batch totalizing

nyameephraim

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Apr 2016
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Hi, please i wish to do batch totalizing ( automatic flow control)
i wish to use Endress+Hauser flow transmitter with Allen Bradley 1400 to do this control for example, if i need 1000 gallon in my batch, i should give an instruction to the PLC once is 1000 the flow should switch off. i wish to do this using the pulse output of the flow transmitter.

please i will appreciate if someone can help me with sample project for this to elaborate me more
thanks.
 
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what do you have right now? Do you at least have rslogix and try'd something by your own?
You cannot expect that someone will have a complete program for you, which you can load into your plc and it will work.
I see that you asked this question several times
http://www.plctalk.net/qanda/showthread.php?t=119315
http://www.plctalk.net/qanda/showthread.php?t=119296
and also on a Rockwell forum.
On plctalk in the download section, there are a lot of examples for Rslogix 500. Check them and see if you can learn
something. Reading help files is also a good source of knowledge, also goolge is your friend.
And if you have specific questions, then i'm sure that someone is willing to help you. But not to do the job for you.
 
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but its always easier to understand with example. (what am actually asking is an example) that is what i mean by ( sample project)
 
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First, how fast are your pulses? Do you require a high speed input, or can a standard input be used. This will be a factor in how you write the logic. Will it always be 1000 or will the volume change? Is it okay to overshoot the target, how accurate must it be? How long does it take your control valve to close? Do you need to have a "pre-act" to shut off early. Are you controlling a pump too?
 
Hello thanks for your contribution.
am using Endress + Hauser flow transmitter, ( yes i require high speed input).
Will it always be 1000 or will the volume change? ( the volume will change more or less than)
it okay to overshoot the target (yes)

i wont use control valve. i will use only pump.
 
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You'll need some device to input the preset volume setpoint for the batch - BCD multi digit switch? HMI?

Presumably you want some indication when the batch is 'stopped', 'filling', 'done'. LED's? panel lights? HMI?

Many flowmeters have frequency output where the pulse frequency varies with flow rate, say, 0-50 GPM = 0-2,000Hz. This is usually a monitored with a 'high speed' digital input on a PLC. This is what I'd use for batching.

Sometimes the flowmeters have a pulse output (relay or solid state) that trips every time a given volume has flowed, say, every 10 gallons a discrete output changes state or cycles. This is usually monitored with a standard discrete input on a PLC.

Some comments on batch control in general:
The assumption is that a flow meter is always full of liquid (no air, not partially full) in order to report the correct flow rate. Vertical down flow is no-no with liquids. Vertical upflow is preferred. If horizontal, put the meter body at a low point so entrained air does not accumulate in the meter body at a high spot in the line.

If your batch control drains the flowmeter, it will take some period of time for the meter to re-initialize when the flow starts.

When the controller turns the valve off, a quick closing valve can damage piping or even a flow meter with water hammer shock. It pays to not slam the valve shut. At a given pressure, its operation will be repeatable, meaning you might have to shut it off at 989 gallons and the remaining 11 gallons flow during the valve shutdown and with whatever drainage there is.

Many batch controls shut down the large valve at, say 95% of setpoint and use a smaller pipe and valve to finish the filling (dribble mode). That might require either a second flow meter or just timing remainding flow.
 
Hello thanks for you contribution i appreciate.
please i need the ladder logic example of this control system, it gives me better understanding.

You'll need some device to input the preset volume setpoint for the batch? (yes)

Presumably you want some indication when the batch is 'stopped', 'filling', 'done'. HMI (yes)
 
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You'll need some device to input the preset volume setpoint for the batch - BCD multi digit switch? HMI?

Presumably you want some indication when the batch is 'stopped', 'filling', 'done'. LED's? panel lights? HMI?

Many flowmeters have frequency output where the pulse frequency varies with flow rate, say, 0-50 GPM = 0-2,000Hz. This is usually a monitored with a 'high speed' digital input on a PLC. This is what I'd use for batching.

Sometimes the flowmeters have a pulse output (relay or solid state) that trips every time a given volume has flowed, say, every 10 gallons a discrete output changes state or cycles. This is usually monitored with a standard discrete input on a PLC.

Some comments on batch control in general:
The assumption is that a flow meter is always full of liquid (no air, not partially full) in order to report the correct flow rate. Vertical down flow is no-no with liquids. Vertical upflow is preferred. If horizontal, put the meter body at a low point so entrained air does not accumulate in the meter body at a high spot in the line.

If your batch control drains the flowmeter, it will take some period of time for the meter to re-initialize when the flow starts.

When the controller turns the valve off, a quick closing valve can damage piping or even a flow meter with water hammer shock. It pays to not slam the valve shut. At a given pressure, its operation will be repeatable, meaning you might have to shut it off at 989 gallons and the remaining 11 gallons flow during the valve shutdown and with whatever drainage there is.

Many batch controls shut down the large valve at, say 95% of setpoint and use a smaller pipe and valve to finish the filling (dribble mode). That might require either a second flow meter or just timing remainding flow.

You will struggle to get a more comprehensive reply to this.
People are not going to do the work for you
You will have a setpoint entered as said above via a hmi or scada or some other device.
Then once the batch has started you count the pulses from your flow switch to see if the setpoint has been reached.....
If it has you will close the feed valve..
 
Hello thanks for your reply, Given an example of something i believe is a way of putting somebody on track not doing his work.

note, i have not asked any body to do the work for me.
(i have also given several examples to people in the field of control)
 
Have you given any thought to using a dedicated Batch Controller? There are many on the market in just about every price range. You could use your PLC to communicate via Modbus to the controller and get data and even start a batch. Of course that will depend on the features of the controller.
 
Hello thanks for the contribution.

As i have stated above that is what i wish to do.

i need some domesticated example,
also i need demonstrated example for (HSC) high speed counters
 

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