I need a magnetic card reader system with communication profibus dp or modbus rtu! Can anyone suggest me?
You are going to need to talk to the various card reader manufactuers. All of the card readers I know of, can provide a RS-232 or RS-485 output data stream (8N1, 2400 to 9600 baud or higher). You could read this data into a PLC RS-232 or 485 port, buffer the data, send it out via the modbus port. You could also use the PLC to do a local lookup, the PLC can ask for a current active card list, compares the buffered data to the recent valid list, opens the door, gate or whatever needs to be done.
So, search on magenetic card readers and ask the various manufactures if they have modbus protocoal type unit available (doubtful, as most all use 232 or 485 to send the framed data to a remote PLC or PC.)
Note a quick search turned up over 40K responses, so do a little searching on your own.
I am not aware of any. Can you perhaps use a Profibus-to-serial interface? (e.g. Wago 750-303 and 750-650).
Sage Automation, Inc.
We have MODBUS protocol stacks that is ANSI C compliant and can be ported to any of the small embedded systems. We also do have converter modules that can be configured for MODBUS communication from any of the proprietory protocol, so let me know if this will serve any of your purpose. Let me know if you need any assistance in this regard.
I think i should explain the process more detailed. I have to use 8 readers. The multidrop cable length between them is 1200 meters. One of the 8 readers must be the master that communicates with the host (Foxboro DCS, Profibus or modbus rtu). That means, all the readers should send the data to the master reader, and the master to the host (DCS).
If you can't find a card reader with this functionality you can always connect to what ever fieldbus you want via a Gateway. The AnyBus Communicator Serial to Fieldbus Gateway connects to the Card reader via RS232/422/485. Data can be sent to the gateway via Modbus-RTU/ASCII, mapped inside the gateway and sent out over Profibus. This might help solve your problem!
Yes. I have found a card reader that works on Modbus ASCII (but not Profibus) at the following web address: http://www.octal-systems.com/products/mcki.html
Hope this helps.