Re: Perfect control of monotube boilers in our lifetimes!
Posted: Tue Mar 13, 2012 8:53 am
Hi Bart,
I couldn’t agree with you more regarding the vibration and marine environment. I remember asking a commissioning engineer what were the plastic struts on each of the control systems boards. He said they were to stop the boards flexing due to vibration from the ships engines; he also added that they were coated in a anti-fungal varnish for when the ships were in tropical climes - we were using them in a power station! With the wire wrapping, we had to ensure that the last three turns included the insulated part of the wire to act as stress relief on the bare wire.
One thing with my controller is that I can unplug it and put in my pocket for safe keeping.
I’m not actually using wire-wrap for this project. The system I use is “Vero-wire”, which has a pink insulating coating that becomes the flux when soldered, i.e. no need to strip the insulation before soldering; the wire’s diameter is only 0.2mm. The board is a gold-plated copper strip matrix type; I just poke the wire through the hole, bend it and solder and then test for continuity.
The controller was a development of a previous one, which was nearly three times the size. The current controller took three days for the layout design and three days to construct. The software development took two years to perfect, including learning the best method to control the monotube!
The software is written in assembler and the system runs in real time, since it has to respond to real-world events.
The main elements of the board are: two thermocouple amps, a display controller, the process controller, a pulse shaper, three RPM chips, a timer and an LED bank.
I have considered using something like the Allen-Bradley Programmable Controllers, but they were far too large to fit in a model boat – might be an idea for a full-size boat though. Another problem was sourcing a low RPM module to measure the pump strokes per minute (SPM) for the range 0.5 SPM to 200SPM and would also update every stroke.
Thanks for your interest Bart.
Keep on steaming!
Ian
I couldn’t agree with you more regarding the vibration and marine environment. I remember asking a commissioning engineer what were the plastic struts on each of the control systems boards. He said they were to stop the boards flexing due to vibration from the ships engines; he also added that they were coated in a anti-fungal varnish for when the ships were in tropical climes - we were using them in a power station! With the wire wrapping, we had to ensure that the last three turns included the insulated part of the wire to act as stress relief on the bare wire.
One thing with my controller is that I can unplug it and put in my pocket for safe keeping.
I’m not actually using wire-wrap for this project. The system I use is “Vero-wire”, which has a pink insulating coating that becomes the flux when soldered, i.e. no need to strip the insulation before soldering; the wire’s diameter is only 0.2mm. The board is a gold-plated copper strip matrix type; I just poke the wire through the hole, bend it and solder and then test for continuity.
The controller was a development of a previous one, which was nearly three times the size. The current controller took three days for the layout design and three days to construct. The software development took two years to perfect, including learning the best method to control the monotube!
The software is written in assembler and the system runs in real time, since it has to respond to real-world events.
The main elements of the board are: two thermocouple amps, a display controller, the process controller, a pulse shaper, three RPM chips, a timer and an LED bank.
I have considered using something like the Allen-Bradley Programmable Controllers, but they were far too large to fit in a model boat – might be an idea for a full-size boat though. Another problem was sourcing a low RPM module to measure the pump strokes per minute (SPM) for the range 0.5 SPM to 200SPM and would also update every stroke.
Thanks for your interest Bart.
Keep on steaming!
Ian