Best PLC!

Hello everyone,

I am doing a fairly simple project and I would like to ask what would be the most suitable (cheapest) PLC for the job. I am getting three different ASCII messages via the serial port from a PC then I am turning a motor on three different positions, so all I need is one output (and 3 inputs). I did this with a SLC 5/04 but I need something smaller. What should I buy? Also I am familiar with Allen Bradley only, so must be easy to programm.

Also is there any tip on making ASCII instructions faster?

Thanks,
Eugen

Automation Direct Click. Software is free.
Lowest cost AB also has free software.
To make ASCII faster, raise the baud rate. If you have control over the messages, reduce them down to single characters.

Thanks Keith,

Great clik PLC is all I need. What is the difference between RS-232C and RS-232?

I guess you were using CH0 on the SLC5/04 in ASCII mode.
Since you are familiar with SLC, an obvious contender would be an ML1100.
It has both a serial port that can be used in ASCII mode, and a swanky ethernet port for everything else.

Also is there any tip on making ASCII instructions faster?

Click to expand...

What do you mean ?
Is the port not fast enough to capture the data ?
Or is the program not fast enough to read the data from the port ?

C is the last revision of the RS-232 standard, since ~1970, when electromechanical teletype writers started being replaced by electronic devices.
For your practical purposes RS-232 and RS-232C is the same.

Thanks guys,

What do you mean ?
Is the port not fast enough to capture the data ?
Or is the program not fast enough to read the data from the port ?

Click to expand...

On my first try the PLC was acting with 1 or 2 sec delay. I added an instruction to clear the buffer with the first pass and now is OK. I am only reading 2 Char, so my question will be should I clean the buffer after every read? And how do I make it dependet to the read instruction? Will the buffer get clogged ?

Thanks again,
Eugen