[Emc-developers] Thoughts on an HOA component

[Eric H. J. <ejo...@ca...>]

Hi all,

One thing I have never liked is having to edit the configuration any time I
wanted to do an I/O checkout or certain maintenance and testing functions. I
was thinking of adding an HOA (Hand Off Auto) component which could be used
for this purpose. 

Typically an HOA 3 position switch looks something like this (pardon the
poor character graphic):


       HAND    OFF   AUTO
                |
                |
     ________   |   _________
            o   |   o 
            ____|____ 

     _______o       o________
    

The closest I have come up with has far as an implementation as a HAL
component is either of the following configurations:

1>--------------------

Pins:
mode bit   // Low = Auto, High = Manual
in0 bit    // Auto mode input
in1 bit    // Value for out when mode = manual
out bit    // Output representing value based on mode

2>-------------------

Pins:
in bit     // Auto mode input
out bit    // Output representing value based on mode

Parameter
mode s32   // 0 = Auto, 1 = Off, 2 = Hand

An analog equivalent to an HOA switch could be implemented for the first
option by making in0, in1 and out floats, while in the second option in and
out would become floats.

Any thoughts on which would be the better implementation, or even a better
way of achieving the same thing?

Regards,
Eric