dakota152

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About dakota152

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  • Birthday 04/21/74

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  1. Thanks for the reply. I have not purchased the valves yet so I could use a speed reducer on the valve to slow the closing of the valves to stop the hammering. This will be much easier than using the PID control on the valves. All I would need to do with this is experiment with the valve closing to see how long it will take and adjust my valve closing point in my logic to account for this. I appreciate your help. I would like to understand the PID function a little better though so I would be able to use it in other instances to control things. I thank you.
  2. Thanks for the reply. I have not purchased the valves yet so I could use a speed reducer on the valve to slow the closing of the valves to stop the hammering. This will be much easier than using the PID control on the valves. All I would need to do with this is experiment with the valve closing to see how long it will take and adjust my valve closing point in my logic to account for this. I appreciate your help. I would like to understand the PID function a little better though so I would be able to use it in other instances to control things. I thank you.
  3. I have been writing simple ladder logic with AB software for a little while but I have been asked to do a project to fill our tank with water. We need to use a control valve to do this to keep our water lines from hammering. It seems simple in my head but I have never done PID control using AB software. I will be using a ML1100 along with an analog input and analog output cards using 4-20mA. I have a the tank on load cells, so I will be bringing in a 4-20mA signal from the scale head into the PLC. I will scale this using the SCP function. It will be scaled in PID scaling. 0 being 0 and 16383 being 5000 in engineering units. I will then have a setpoint that I want to fill the tank to. This setpoint will come from the HMI panel (F8:0). This is the point I want the valve to close off completely and stop the tank from filling. I am just not sure about how the logic should be to do the PID function to control the valve. Can anyone help me with this. I am in a time crunch with my boss because he wanted it yesterday. Like most bosses they think things are snap your finger and it is done. Does anyone have anything already done this way? Can you send me a copy of a program like this? Any help would be greatly appreciated. Thanks
  4. I am trying to put together a program for a control valve and scale combination. I will be using a ML1100 PLC, a 1762-IF4, and a 1762-OF4. I will have a Mettler Toledo IND560 scale head with a 4-20mA output module. Will send the 4-20mA signal to the 1762-IF4 input module to get my reading from the scale. I will have a HMI touchscreen so the operator can enter the amount of product to add to the tank. This number will go into the PLC and subtract from the scale value to give you the stop amount to get to. I will be sending a 4-20mA signal out to a control valve to control the flow of the liquid. Will be using PID to close the valve the closer you get to setpoint. I have never used Allen Bradley analog output modules before so I am not sure about the scaling on them. Does anyone have an example of something like this? Or an example of an analog output ladder diagram? Any help would be greatly appreciated.