[Dsg-hallc_controls] NMR - PLC Interface

[Cynthia Keppel]

Hi Mike, Brian, 

I think I need more input... will the cost for one option be the ~$70 x 2 for implementing the Python modules as Brian is suggesting, with the ~$30k for new NMR units the cost for a different option - or are these two the same thing?

Help!

Thanks,
Thia

----- Original Message -----
From: "Mike Fowler" <fowler at jlab.org>
To: "dsg-hallc controls" <dsg-hallc_controls at jlab.org>, "Cynthia Keppel" <keppel at jlab.org>
Sent: Friday, June 8, 2018 4:22:38 PM
Subject: Re: [Dsg-hallc_controls] NMR - PLC Interface

Hi,

It is my opinion that the need for this project should be reviewed and 
possibly delayed until such time that the NMR vendor has resolved the 
communication problem.

Currently the HMS dipole older NMR unit covers most of the dipole 
operating range, and regulation by current appears to be sufficient over 
that range. The SHMS Dipole is currently regulated by current which may 
be sufficient for the near future.

I believe having additional hardware and software external to the PLC 
that is subject to failure is not an ideal solution. Implementing the 
new NMR units for the SHMS also comes with an additional investment of 
about $30K.  Without a reliable solution I question the current need to 
proceed.

Steve and Thia please comment.

Regards,
Mike




On 6/8/2018 1:05 PM, Brian Eng wrote:
> Since there is currently no direct way to interface the new NMR with the PLC (MODBUS would work, but is at least 1 year away according to the vendor) and none of the existing devices used by Halls B/D will work we're going to need to develop something ourselves.
>
> Despite the communication issues discovered with the NMR (that the vendor is aware of and working on) the proof-of-concept of using Python modules as a go between the devices showed it could be a viable solution.
>
> The next step would be to order the hardware that would run this. The plan is to use a small SBC that runs Linux, I was hoping to order through webstock but I couldn't find any newer models. So we would need to use a PCard for the order.
>
> Each board/setup would be ~$70 and we'd like to order at least two of them.
>
> Is there someone in Hall C that normally handles PCard orders or should we just place the order ourselves using COPS.PHALLC?
>
> Thanks
> --
> Brian Eng
> Detector Support Group
> 757-269-6018
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