View Full Version : Plc
June 6th, 2002, 03:12 PM
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?
June 6th, 2002, 03:21 PM
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.
June 6th, 2002, 03:32 PM
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.
June 6th, 2002, 03:35 PM
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.
June 6th, 2002, 03:58 PM
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.
June 6th, 2002, 04:33 PM
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.
June 6th, 2002, 04:37 PM
The operator is notified via the computer screen...just a pass/fail message.
June 6th, 2002, 05:38 PM
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.