Could this be another possible controller. Certainly the programming
 language will have a shorter learning curve.
 C. Smith

 Possibly but I'll bet it is not $90 :)

 Paul Lamar

Hey I happen to be an old PLC programmer and controls engineer. It depends
on what you want to control if you can tell me. If not just give me
examples. The PLC was designed for electricians to use and trouble shoot
equipment with. It uses a hibrid program that mimics the ladder diagrams of
old that are an industry standard. You occassioinally see them in some
washing machines or appliances etc. They provide high speed universal
troubleshoot unlike written cryptic programming code like C or C+ CPP and
so
on. Also the nice thing about what is refered to as Ladder logic is that it
can usually be changed on the fly in realtime without shutting down,
compiling and downloading. Depending on what your using it for, this can be
good. Also ladder logic is intuitive and once you understand it you
understand most PLC's and many DCS systems. You could essentially make
changes while flying to logic or just parameters, values, setpoints and so
on. I can help you if you decide to go this route and don't be shocked at
the price, some are very reasonable, some are big bucks. Allen Bradley
www.ab.com/ is a top of the line PLC that is very common in industry if
you
want a high end reference.

Also do you want an input screen called a MMI or HMI. The MMI is the
Man-Machine Interface of old. Then women came into industry and they
changed
the name to HMI, Human-machine interface. It is essentially a monitor with
on/off buttons and so on, touch screen type of thing that is programmable
to
your specific operation.

Hell I can flood you with free info to fill your library if you want. I
love
this stuff and can talk forever about state of the art controls.

This particular PLC is made by Galil Motor Controls - (there are millions
trying to get in the market)

http://www.galilmc.com/learning/tutorials.php

http://www.galilmc.com/support/catalog.php    Order their free hardcopy
catalog here or get the ecat.  I'm attaching one for you.

http://www.galilmc.com/

How many I/O's do you need and of what types. What type of operations do
you
have going on? AI, AO, DI, DO and so on. I do process control and
automation, robotics etc if I can help you in any way. I haven't heard any
discussions about controls until I seen this post.

Nevada Bruce

We have up to ten zero to five volts analog signals to record and display
on a CRT. A minimum of ten bit resolution.

We have four injectors to control with pulse width modulation.

And we have one RPM to measure in real time and record and display.

We have four spark plugs to fire. Two of which can be fired with
the same signal.

All this must be done in 8 milliseconds.

Paul Lamar

Thank you, that is a start. What I didn't see was an encoder of sorts for
precise timing of these devices, I suspect this is for a rotary engine
correct, so in other words if you want these outputs to happen at a precise
time relevant to TDC (in recips), I think we would want a pulse train coming
in referenced to TDC or what ever that is called on rotaries ( I get to
learn too)  Am I correct or is there something I don't know about?

Q: Is your intent to build an ECU where you can control/modify it?
Q: Is this in addition to a ECU or stand alone?
Q: Have you considered redundancy or triple redundancy for safety or is
there some type of manual backup?
Q: How many processor units do you want in the end? One or more? In other
words, will you be making more for other engines? I ask this because
possibly a PLC wouldn't be the best way to go. I don't have a feel for it
yet.
Q: Have you explored the world of micro controllers yet, with these, once
you get your prototype perfected, you can black box your code and produce a
zillion via china or do it yourself like copying DVD's (what MIcroSoft
should be doing with their operating systems if they wanted to improve their
product - silly statement - of course not)

*We have up to ten zero to five volts analog signals to record and display
on a CRT. A minimum of ten bit resolution.*

This can be done simple and with an operator screen once everything else
is resolved.

*We have four injectors to control with pulse width modulation.
*
Q: can we define this a little more? I assume by pulse width, we need to
control duration of a high signal like a DO (can we use a DO?) at the same
amplitude, ie: the longer the duration of the DI, the more fuel, is this a
correct assumption? This also needs to be timed to a specific crank position
reference signal is that correct?

*And we have one RPM to measure in real time and record and display.
*
Q: I think here we would use the Crank Position and location (help me
with the proper description of what I'm trying to say here please) we can
use this for many other computations relating to start stop time to
position.

*We have four spark plugs to fire. Two of which can be fired with
the same signal.*

Q: can these be fired with DO's Digital Outputs right? But the timing of
these needs to be variable as do the injector signals in relationship to the
crank shaft position (or rotary cycle timing) I'm new and ignorant of the
Rotary engine, I understand the rotor cycle to crank shaft is 3:1 is that
correct?  We need a way of identifying crank shaft position from rotor
position so I need the proper words to describe each including a short
acronym of your choice. This is to communicate between each other to avoid
confusion. Building and sharing a glossary would be good to start with for
someone.

*All this must be done in 8 milliseconds.
*
Q: for my benefit, can you help define the complete rotary cycle posible a
hand drawn scetch to begin with, when the events will ocur in the cycle, the
max RPM, the min cycle width (cycle frequency at the max RPM, cycle freq at
minimum RPM)

I am seeing some DO's (don't have a handle of the quantities yet, probably
one for each injector and one for each spark plug.)

Probably a digital encoder (pulse train) for timing purposes and fine
control and a DI for TDC crank position. The RPM can be derived from this
DI.

Q: can you elaborate on the .008 seconds in this discussion? Is that the
maximum cycle width at max rpm? (I haven't done any of the math yet until I
define the full scope of what is happening. I don't want to assume things
and get them in my mind.) Also what is the best resolution we are striving
for, how many degrees, or parts of a degrees do we need to be able to
control to. These are the things that affect the type and cost of the
processor, and what type processor to use. (processor speed and so on)

Q: Communications: What method do we want to describe a partial degree in.
(like degrees, minutes, seconds or decimals. I prefer using decimal but it's
your call. I just want to make sure we are always talking apples and apples.
Example: does 1.50 mean 1 1/2 degrees or does it mean 1 degree and 50
minutes?)

Example: turning on and off room lights are the low end cost, where
the operation of a high speed I/O is more in the high end. When that room
light is required to turn on and off in a specific time frame at an absolute
time, it becomes more expensive.  Where a $90 processor may be able to
handle the analog inputs just fine, it may not be able to handle the more
intricate high speed DI's, DO's and pulse input's as frugally.

Q: do you want data logging and data storage capacity? You can be thinking
about it. We don't have to know up until it's time to spec out and purchase
something.

Q: How many people are involved that can be collecting sale information? I
can tell you that this market is vast and changing. There are new things
coming out every minute unlike some industries like automotive where it's
about 75 years behind the technology curve.

Q: Are you considering monitoring/logging various temperatures, exhaust gas
oxygen? These are simple and cheap but need to be defined in the process.

I hope I didn't overwhelm you with stupid questions. I don't know you well,
I know you are very smart however I don't know your strengths and weakness
in particular fields so please take no offense at my dumb questions.

Also is there a test engine on a test stand somewhere that can be used?
If we can define our exact operation, it does not have to be said what it
will be used on, we can let the vendors to the majority of the research on
what is best for this application. They have applications engineers that do
nothing but that. My suggestion is to spend 90% of our time/energy
brainstorming and defining a good spec to give to multiple vendors and let
them tell us what they have, the cost and why we should use their product.
This is a vast area. It's possible that with research there is one already
out there that can suit our purpose so we need to decide too, do we want to
invent this wheel from scratch for some reason or will we accept someone
else's work? Many things to think about. I'm only now got in this discussion
so possibly these things have already been discussed and resolved. I'm only
thinking of the many possibilities of how to skin this cat . . . I love cats
so I don't mean that literally. I should use the word politician, everyone
hates them :-)

Bruce

http://www.parallax.com/

http://www.c-stamp.com/index.htm?gclid=CKeLoK3XwKACFQMhDQodwCoLUg


http://www.google.com/search?source=ig&hl=en&rlz=1R2ACAW_enUS370&q=microcontrollers&aq=0s&aqi=g-s1g-sx9&aql=&oq=micro+controllers
Also see:
Programmable logic device
Field-programmable gate array (FPGA)
**

Brief overview of a micro controller v. micro processor.


*A microcontroller is a specialized form of microprocessor that is designed
to be self-sufficient and cost-effective, where a microprocessor is
typically designed to be general purpose (the kind used in a PC).
Microcontrollers are frequently found in automobiles, office machines, toys,
and appliances.
The microcontroller is the integration of a number of useful functions into
a single IC package. These functions are:

The ability to execute a stored set of instructions to carry out user
defined tasks.
The ability to be able to access external memory chips to both read and
write data from and to the memory.

Basically, a microcontroller is a device which integrates a number of the
components of a microprocessor system onto a single microchip.

So a microcontroller combines onto the same microchip :

The CPU core (microprocessor)
Memory (both ROM and RAM)
Some parallel digital I/O
Also, a microcontroller is part of an embedded system, which is essentially
the whole circuit board. Look up "embedded system" on Wikipedia.
The difference is that microcontroller incorporates features of
microprocessor(CPU,ALU,Registers)along with the presence of added features
like presence of RAM,ROM,I\O ports,counter etc.Here microcontroller control
the operation of machine using fixed programme stored in Rom that doesn't
change with lifetime.

http://wiki.answers.com/Q/What_is_the_difference_between_a_microprocessor_and_a_microcontroller

Nevada Bruce

Most of the answers are here.
http://www.rotaryeng.net/fuel-injection.html
And here.

http://www.rotaryeng.net/mech-fuel.html

Paul Lamar