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Guest
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Hi all
I'm looking for recommendations for low cost PLC/single board controllers that I can easily access through a serial port on a PC. By this I mean that the manufacturer should provide protocols for serial communication, at least as far as the basics go - I want to be able to turn on and off digital outputs, read digital inputs and so on, and all through a standard serial port, so that I can use a PC running Linux or a Mac or whatever machine I have available. (I'm happy to have the controller running a program to provide regular polling of the inputs if that is necessary, and in general the PLC will end up running a standalone package anyway)
The background is that I dont want to be tied to proprietary software (usually windows, with the manufacturers only providing their development systems and process monitoring apps for that) when I'm doing development. When I'm working on a project, I want to be able to monitor what is going on, collect data, and override outputs and not be tied to a manufacturers proprietary software for doing so.
I program in Tcl/Tk, and its very easy to do complex graphical interfaces, number crunching, data collection and so on. I can open up the serial port and then read and write byte streams with very simple commands - all I need is the right controller and the protocols. (The program will also work on a Linux box, a mac or whatever...)
So far I have found the SplatCo controllers (the actual PC interface/development system is for windows only, but they'll give you the serial protocols), and the DataTaker, which is more of a data acquisition device but can be controlled from a dumb serial terminal. Other manufacturers seem loath to give away any useful information on communication protocols (presumably they'd rather you purchase their software and not "roll your own")
Any suggestions or feedback would be appreciated.
I'm looking for recommendations for low cost PLC/single board controllers that I can easily access through a serial port on a PC. By this I mean that the manufacturer should provide protocols for serial communication, at least as far as the basics go - I want to be able to turn on and off digital outputs, read digital inputs and so on, and all through a standard serial port, so that I can use a PC running Linux or a Mac or whatever machine I have available. (I'm happy to have the controller running a program to provide regular polling of the inputs if that is necessary, and in general the PLC will end up running a standalone package anyway)
The background is that I dont want to be tied to proprietary software (usually windows, with the manufacturers only providing their development systems and process monitoring apps for that) when I'm doing development. When I'm working on a project, I want to be able to monitor what is going on, collect data, and override outputs and not be tied to a manufacturers proprietary software for doing so.
I program in Tcl/Tk, and its very easy to do complex graphical interfaces, number crunching, data collection and so on. I can open up the serial port and then read and write byte streams with very simple commands - all I need is the right controller and the protocols. (The program will also work on a Linux box, a mac or whatever...)
So far I have found the SplatCo controllers (the actual PC interface/development system is for windows only, but they'll give you the serial protocols), and the DataTaker, which is more of a data acquisition device but can be controlled from a dumb serial terminal. Other manufacturers seem loath to give away any useful information on communication protocols (presumably they'd rather you purchase their software and not "roll your own")
Any suggestions or feedback would be appreciated.