pid level control

hey guys i need help urgently i am in need to program aa s7 300 plc siemams and here is the requirements:
You are required to program the plc to implement automatic or manual PID level control on level control rig. You required to implement level control incorporating the following:
Differential Pressure Meter
Variable Speed Drive (VSD)
PLC with analog I/O
Electronic Chart recorder.
You will be required to configure the VSD.

Auto/Manual control must be via a on/off switch connected to the PLC.
In manual mode the VSD must be controlled via a additional analog input on the PLC.
Chart recorder must display the liquid level also coupled to the PLC.
Use a variable table to display the following:
• Liquid Level
• Auto/Manual mode
• VSD analog input signal

can any one help in terms of how i should go about in solviong this problem i am a rookie




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Define your urgency - do you need to have this working today ?

well i would love to get this program up and runing in the next two days it would be great

pls can u help... i am new to this plcs im using a s7300 siemens plc and use to programming in ladder

This appears to be a student problem. Most guys here do this for a living, so we are unlikely to do the programming for you. Here are some hints:

Make an I/O list for the PLC. This often helps programming because you have to think about what the PLC is responding to and what it is manipulating. Think about the function of each device.

Think about how you would control the system by hand.

Write a simple description of logic in plain language - as if you were explaining to a buddy how it works - in detail. "First I check the level, then I compare it to setpoint, .......

Then start programming with something simple like the chart recorder echoing the input. This eliminates the intimidation of the blank page (or screen).

Enjoy

thans alot tom ... appreciate it. u mind me emailing u sum more questions as i go along, coz im strugling between which pid function to use wherether the fb41 or fb58. pls not it is an continuous automatic control... anthor q would be how do i connect up the recorder does it com from the outputs

Take a look at the standaard blok for continius control (FB41). This blok does a lot off things you require.