Internet PLC Forum
General => Technical support => Topic started by: Remso on December 02, 2002, 04:22:48 PM
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I want to connect a swipe card reader to T44H-pnp. The PLC will be connected to the serial port of a PC.
When a card is swipped in the reader I should read the card info using serial port & validate the info in the PC before controlling an output attached to the PLC.
1- How do I connect the reader to the PLC ?
2- Any code to read the input of the card reader ?
3- Is T44H-pnp a correct PLC to do that job ?
4- I don't know about ladder programming, will I need it for that purpose ?
Any info will be appreciated Thanks.
Regards,
Remso
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The H-series (including the T44H) are not able to process data from the serial port. Their serial port are really slave-only communication port that accept predefined host link commands.
Enter the M-series PLC, and you are able to use any of the M-series PLC (T100MD888+, 1616+, 2424+ or T100MX3224R+ and T100MX4832) to process serial port data very easily and control any output based on the data received from the serial port. The M-series PLC was originally designed with such an application in mind!
Ladder logic is not strictly necessary because most of the serial communication command are handled using the powerful TBASIC commands. You do need to know a bit of ladder logic so that you know how to trigger the custom function that processes the TBASIC command.
All M-series PLC has two or 3 serial ports (RS232 or RS485) and you can connect to your card reader using either direct DB9 cable or null modem cable. It depends on your swipe card reader.
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Can I connect more than one swipe reader to the same serial port on the PLC ?
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Provided your swipe card reader runs on RS485 and recognize some kind of ID along with its commands.