from the Student department...
Getting Data from a PLC Automatically
PLCs and related questions. topic
Posted by Kevin on 9 February, 2012 - 10:12 am

I am trying to collect information from a PLC for a college project. This Omron PLC is connected to 6 stations on an assembly line. I am trying to collect information like times for when the pallet enters station A and exits station A and so on.

I have currently identified the addresses needed for each station. For example when using time chart monitoring on the sysWin software I can see when address 001.00 goes high when enters station A and goes low when exits station A.

How would I go about timing this interval when the pallet is in the station automatically? Would it be possible to program in a timer into the ladder logic which could send the output time into a text file maybe?

All help will be greatly appreciated,

Posted by Steve Chilton on 24 February, 2012 - 6:48 pm

Yes this is of course possible. It depends on what accuracy you need from your timer and the format of the data to be sent.

Basically you can
When the input 1.00 is ON
AND with 0.1second pulse
into @INC instruction with an un-used memory area (say H0000 [sometime HR0000] as this will hold the value when the PLC is powered down).
The @ is very important as it only increments on the rising edge of the input (every time the 0.1sec becomes true)

This will give you the time in 0.1sec accuracy in the station.

Then we can use the falling edge of the input 1.00 to 'SEND' the data.

Depending on the PLC model this will typically need to be configured (and the protocol setup for the data transmission) with many data formatting options available (BCD to ASCII, HEX to ASCII) depending again on the PLC type and number format you are using.

If you can give me some more info I'm happy to help.


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