ASM Interference (fwd)

Vera Mainz (mainzv@aries.scs.uiuc.edu)
Tue, 17 May 1994 12:53:10 -0500 (CDT)

Forwarded message:
> From Kinney%WPGATE.VAXC.NSWPMAC.decnet@sci.Arco.COM Fri May 13 16:23:26 1994
> Message-Id: <9405132123.AA08731@Arco.COM>
> Date: 13 May 94 17:23:00 EST
> From: "WPGATE::VAXC::NSWPMAC::Kinney" <Kinney%WPGATE.VAXC.NSWPMAC.decnet@sci.Arco.COM>
> Subject: ASM Interference
> To: "cvxdrk" <cvxdrk%arco.com@inetg1.Arco.COM>
> Cc: "mainzv" <mainzv%aries.scs.uiuc.edu@inetg1.Arco.COM>
>
> Vera:
> I haven't seen my posting since I attempted it a second time at
> 4:12PM EST. I'm assuming that something is wrong with one of
> our mailers. If you discover a problem from my end, I would
> appreciate any advice you could offer. Thanks again.
>
> Here is the posting:
>
> We are currently in the process of installing a 300 MHz
> wide-bore instrument in the same room as a Varian 400 MHz
> standard bore with an ASM100 autosampler. We have noted that
> the lock signal on the new 300 is taking a large hit when the
> autosampler is in use. To be specific, the DC motor that raises
> and lowers the autosampler arm on the ASM100 is causing the
> disturbance when the motor reverses phase to go from a downward
> motion to an upward motion. The autosampler is positioned
> roughly 12 feet from the center of the 300WB field, presumably
> outside of the calculated 5 gauss line of 9 feet from the center
> of the 300WB magnet.
>
> While the manufacturer of the 300 MHz instrument might try to
> argue that this is an _ideal_ challenge for their digital lock
> system, it is nonetheless a challenge we would prefer to avoid.
> Has anybody else seen this problem and/or found a good
> workaround? Would shielding of the motor create bigger problems
> for the 400 than the potential benefit for the 300? Have any
> electronics wizards attempted to swap out the brutally abrupt
> phase-switching relay on the DC motor for a kinder, gentler type
> of switch?
>
> Please send any and all suggestions to cvxdrk@arco.com and I'll
> post a summary (let me know if you prefer public anonymity) in a
> week or so. And thanks to everybody for all the useful
> suggestions and information over the past year!
>
> David Kinney
> ARCO Chemical Co.
> 3801 West Chester Pike
> Newtown Square, PA 19073 USA
> (610)359-3455
> Fax: (610)359-5573
> EMail: cvxdrk@arco.com
>
>