I do a lot of PLC programming and have used Automation Direct PLCs as I/O / Controllers attached to LinuxCNC via Modbus RTU. The Click series of PLCs are cheap and they have relay output cards.
However if you have a lot of I/O and need auxilary control besides remote I/O to LinuxCNC, I think the best smaller PLC out there right now is the Siemens S7-1200 series. The software is very powerful and can save a lot of development time for a one-off solution. They aren't the absolute cheapest, but from a functionality standpoint they are superb controllers and they also support Modbus TCP without additional modules or software add ins. They are also a lot of parts and pieces on Ebay because they are so popular. Watch out for the firmware level and don't buy anything with firmware older than 3.0. CPUs with firmware prior to 3.0 cannot be upgraded to 3.0 due to hardware changes. Dave On 9/15/2015 2:53 AM, Sven Wesley wrote: > Yo! > > I have this old injection moulder and the electric mayhem has degraded to a > point were I need to either throw out the machine or rebuild. The machine > is mechanically in good shape so I lean towards the latter. > > There are a billion of limit switches and the hydraulic system is managed > by electric solenoids via relays and timers. I need a lot of IO-ports. I > could of course get a Mesa card but this machine has no performance goals > and an old PC with a few parallel ports should be more than fine. > > What cheap solution do I have to play with? > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
