Plc

I have a software process that programs an RFID chip. A Box (containing the chip) is slid down a ramp and it hits a stop. Above the stop is the RFID encoder. currently once the chip has encoded successfully the operator manually releases the stop to let the box continue down the ramp. I would like to automate the stop...Someone suggested a PLC to me...I want this to be even driven...meaning only after the chip has encoded successfully can it be released. Can My software "talk" in real-time to the PLC to produce these results?

-engineerwannabe

Your software can communicate to a PLC. Others on this message board are going to have to fill you in on how, because I've never tried this sort of thing before.

RSLinx (Allen-Bradley) supports the protocols (DDE?, OPC?, ActiveX?) that are necessary to link the PLC memory tables to your application in the same way you would link a spreadsheet or database.

AK

If I understand you correctly, you're using your own proprietary softward to encode the RFID tag rather than using a commercially available product.

If that's the case, then your system may be a good fit for a soft PLC. That's software that runs on the PC and controls the machine functions in response to input data from sensors and operator actions.

If you're using a commercial RFID system, the manufacturer probably has application experience integrating their hardware with PLCs.

Yes...it is my own software...suggestions on where to find more information on Soft PLC. Also, where can I look for a device to to stop the box (weighs 1 oz.) when travelling down my incline.

A query on Google or any other search engine will give you plenty of leads to companies offering soft PLC products. A pneumatic cylinder would be a good candidate to actuate your stop mechanism.

I got a question? Once the RFID has been encoded how does the operator know to open the gate?

If you are turning on a light/horn etc to notify operator then you are halfway to automating it now. You could use that signal to start a process to open/close the gate. May not need a plc if the gate is only thing involved, a timer may suffice.

The operator is notified via the computer screen...just a pass/fail message.

If you are programming in a high level language like "C++" or Visual Basic and you have an ethernet or serial port available the easiest route is to use a remote I/O block like Opto 22. They have sample programs that you can patch into your software. Essentially you write a command to the serial port to turn on an output to open a valve to move the gate. Contact your local supplier and he will be able to offer some assistance in selection and progamming.