DRO switch

[RedpiperbobParticipant @redpiperbob16487]

Hi All
I have a mill with a 3 axis dro setup on it and a lathe with 3 axis dro each uses Allandale scales.

I
have only one display unit what I would like is an electronic switch
that would allow me to switch between the two different inputs. can
anybody help with a curciut.

Sorry if this is the wrong place to put this but I could not find a beeter heading.

Thanks in advance Bob

[RedpiperbobParticipant @redpiperbob16487]

[Les Jones 1Participant @lesjones1]

Hi Bob,

I am making the assumption that these are the quadrature scales with TTL outputs. Here is one way to switch the scales over. (NOTE this will NOT work with the Chinese scale that use 2 x 24 bit protocol.)

Be aware that you can not switch back and forward between machines without resetting the zero reference. This is because quadrature scales do not give out absolute position information. They only tell the DRO that they have moved one unit of resolution up or down. There are many alternative ways to solve this problem for example one of the switches used to switch a parallel port printer between computers.

Les.

[RedpiperbobParticipant @redpiperbob16487]

Hi Les

Yes they are Sino scales and you sir are a star that is exactly what I was looking for.

Now to Eagle to make a board

Thank you very much

Bob

[Les Jones 1Participant @lesjones1]

Hi Bob,

I drew this diagram with eagle so if you want the file send a message using this forums message system with your email address. I think that method is safer than putting your email address in these pages. If I was building a one off of a simple circuit like this I would use stripboard. If the DRO is capable of providing enough current you could leave the + 5V connected to both sets of scales rather than switching it.

Les.

[RedpiperbobParticipant @redpiperbob16487]

Hi Les

The offer of the file is very good of you but as you say there is very little in the curcuit so I think I will use stripboard.

Thanks Bob

[Billy MillsParticipant @billymills]

Another way would be to use a multiway connector on the display and matching connectors on the machines so you could have the display in just the right spot for each machine. If everything is grounded down there is no static risk in swaping the display over but keep the ground on the display.

Regards

Alan.

[RedpiperbobParticipant @redpiperbob16487]

Thanks for that sugestion Alan but the board is made and the box for it is almost done

Bob

[RedpiperbobParticipant @redpiperbob16487]

Hi Les

just thought you would like to know the switch is up and running. on the mill and the lathe . It works a treat.

Thanks once again

Bob

[Les Jones 1Participant @lesjones1]

Hi Bob,

Thanks for letting me know it works. When designing something no matter how simple it is always possible to overlook something. There is always this slight doubt when you have not built and tested the circuit yourself.

Les.

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