As is usually the case, the hardware is probably the least critical system element; firmware and a development environment that is flexible and tailored to the needs of someone who may actually prefer to "program with a soldering iron" is the key element, in my experience.
I have used a bunch of Galil RIO-471x0 PLC's http://www.galilmc.com/products/rio-47xxx.php They are I/O dense, have a "free" development environment, and best of all, have Ethernet connectability plus HTTP and TCP-Modbus compatibility. We did design a breakout board for the I/O that allows the use of plug-in solid-state relays and resistors for 4-20ma loops, plus ruggedized terminal blocks. We did just as Greg proposes to do: sent a board layout to a service bureau for "instant" PCBs. These PLCs sell for maybe $250 and have opto-isolation, built-in PID routines, counters, etc. and can do floating point arithmetic and lots of other cool stuff as well. But the real beauty is the Ethernet! We strung 17 of these units together on one drying system. They are very robust and nicely packaged. With a wireless point of presence, you can lie in bed, with your laptop on your belly, and drive your gasifier! Galil's strength is in motion control and we use these devices to move dampers, control valves, monitor safety systems and regulate system variables of all kinds. Plus they are industrially hardened and nicely packaged. Downside? No RS-485 (only RS-232). I am in full sympathy with Greg's ambitions, but it's nice not to have to re-invent everything, every time! I love to build controllers, but the software, especially at the device level, can be an impediment, especially with a real-time, multi-tasking OS. Yes, it's fun to do, but this approach works best, methinks, at 1,000+ unit level, where development effort can be reasonably amortized. Having a controller with a speedy RISC MCC and all of the development firmware in ROM for less than $300 (OEM) is hard to pass-up. But good luck Greg, in any case! Mark -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Jeff Davis Sent: Sunday, January 23, 2011 9:32 PM To: Discussion of biomass pyrolysis and gasification Subject: Re: [Gasification] Gasifier Automation Circuitry for Sale Doug, I have an Arduino, just wish I had the time to dig into them! What a tool for the money. Jeff On Sun, 2011-01-23 at 22:42 -0600, doug brethower wrote: > > http://en.wikipedia.org/wiki/Arduino > > -- ________________________________________________ www.puffergas.com Sent from any port in the storm via Acer netbook & Ubuntu Remix. _______________________________________________ Gasification mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenerg ylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/ _______________________________________________ Gasification mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/
