While this has been a matter of some debate. I vote for a conventional Linux driver. The file descriptors can remain open and readers can store readings as they occur. My use for an encoder board might even be best served by a
realtime process that can timestamp the readings so velocity can be accurately derived from the rate of change. This would be useful for robot
and machine tool kinematics. Under motion, there is a great deal of data to be processed so speed and efficiency are important. I have a project on the far back burner that involves running a mill on Linux so I am personally interested. There is support for an encoder board from Servoes to Go in
the EMC project from NIST. That should provide an idea on how to proceed.

Regards

cww


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> This is my first posting to the list, I 've been lurking for about a
> week.

Welcome!

> I liked the idea of four or more MMs for the application, where one is
> the Virtual table one was the I/O table, one was a force table and one
> was the latch table. For inputs, you OR the I/O and the force table store
> the result in the Virtual table, scan the "ladder". For outputs you XOR
> the virtual, force and latch tables then store the result in the I/O
> table. This of course would be a problem with the analog values.

In my IL, I do latched and normal outputs simply by having the OUT instruction turn the output off when its condition is false.

There are separate SET and RST instructions for latched outputs.

The only thing to watch out for then is that if you JMP over an OUT, it obviously won't turn the output off - but that can be a caveat on the JMP
instruction. (The JMP instruction is an impurity in ladder anyway.)


Jiri
--
Jiri Baum <[email protected]>
Windows is not popular. Windows is *widespread*. Linux is popular.

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Latches are useful, but personally I mostly use self latching circuits/networks for most things.

The only place I really use SET/RESET is in implementing SFCs or state machines like you.

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