S
Stan Brown
On Fri Jan 21 10:11:37 2000 Dave West wrote...
>
>What has the HMI got to do with the logic engine aprt from querying it for
>data from time to time?
Absolutely correct. And once again, I think the HMI is a big enough project (or 2 projects) all it's own.
>As for the poor terminology why do can't we give things names and use
>them. In my opinion we should have the following items:
>
>Scheduler, a programme that sequences the execution of tasks (we could
>call it PLCsched).
Agreed,
>Input scanner, a programme to scan the physical input devices and make a
>copy in a data table (say PLCIscan).
Agreed, but we need multiple ones of these. If only to support different brands of hardware.
>Logic engine, a programme to scan the machine logic (say PLCengine).
Agreed, but again, we need to allow for multiple ones of these, for instance to process different languages.
>Output scanner, a programme to take an output data table and pass the
>values on to real output drivers (say PLCOscan).
I think this can be combined with the input scanner.
>Communication handler, a programme to handle requests for data from other
>programmes EG. HMI or monitor programme or logic compiler (say PLCcomm).
Probably at some point in time. I am not certain we need this for V1.0
Additional tasks as I see them:
Timer execution task(s)
Counter execution task(s).
PID execution task(s).
Motion control execution task(s).
Editor/monitor/documentation package.
>Any way I think we are spending too much time discussing terminology
>simply because most of us (myself included) are lazy typists and try to
>describe something in as few key strokes as possible
Guilty as charged :-(
--
Stan Brown [email protected] 843-745-3154
Westvaco
Charleston SC.
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http://linuxplc.org/mailman/listinfo/linuxplc
>
>What has the HMI got to do with the logic engine aprt from querying it for
>data from time to time?
Absolutely correct. And once again, I think the HMI is a big enough project (or 2 projects) all it's own.
>As for the poor terminology why do can't we give things names and use
>them. In my opinion we should have the following items:
>
>Scheduler, a programme that sequences the execution of tasks (we could
>call it PLCsched).
Agreed,
>Input scanner, a programme to scan the physical input devices and make a
>copy in a data table (say PLCIscan).
Agreed, but we need multiple ones of these. If only to support different brands of hardware.
>Logic engine, a programme to scan the machine logic (say PLCengine).
Agreed, but again, we need to allow for multiple ones of these, for instance to process different languages.
>Output scanner, a programme to take an output data table and pass the
>values on to real output drivers (say PLCOscan).
I think this can be combined with the input scanner.
>Communication handler, a programme to handle requests for data from other
>programmes EG. HMI or monitor programme or logic compiler (say PLCcomm).
Probably at some point in time. I am not certain we need this for V1.0
Additional tasks as I see them:
Timer execution task(s)
Counter execution task(s).
PID execution task(s).
Motion control execution task(s).
Editor/monitor/documentation package.
>Any way I think we are spending too much time discussing terminology
>simply because most of us (myself included) are lazy typists and try to
>describe something in as few key strokes as possible
Guilty as charged :-(
--
Stan Brown [email protected] 843-745-3154
Westvaco
Charleston SC.
_______________________________________________
LinuxPLC mailing list
[email protected]
http://linuxplc.org/mailman/listinfo/linuxplc