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PLC-function Block Programing

PLC-function Block Programing

PLC-function Block Programing

(OP)
Just started using Crouzet PLC function block programming.  I have the basics but I am having trouble writing a step that uses a 4-20mA signal (ultrasonic tank level sensor)and calls via modem when the level drops below a fixed level after it begins to fill.  This would only happen due to evaporation or a leak.  The process is a batch process so the tank should never decrease in level until it is processed by the operator.
thanks to anyone that can help.

RE: PLC-function Block Programing

Be careful about your own assumptions.
The phrase "should never" should never appear in your documentation of the software.

E.g., when a tank fill valve opens, it is possible for the incoming flow to disturb the surface in such a way that the level seen by a transducer will go down, as in a standing wave.

 

Mike Halloran
Pembroke Pines, FL, USA

RE: PLC-function Block Programing

(OP)
Thanks for the tip but we have the sensor isolated with a standpipe and have been using it for 6 years without any problem.  My concern is more about evaporation and level loss since we are now processing a different fluid.  I'm more interested in help with sequence of the function blocks to write the program.

RE: PLC-function Block Programing

(OP)
Good Idea.  I saved and attached the program file as a PDF.  The analog input at the bottom of the logic page is the tank level sensor.  I want an alarm message (such as input 2) if the level drops while the tank is filling over a 1 week period of time.

RE: PLC-function Block Programing

You might also check out Tek-tips - a sister site to this one that specializes in programming - and I think PLC

RE: PLC-function Block Programing

(OP)
thanks,
I'll check it out.

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