[chbot] RS232 FILTER (Marshland Engineering)

Mark Atherton markaren1 at xtra.co.nz
Tue Oct 25 04:00:06 BST 2022 

My sentiments entirely !

On 25/10/2022 2:53 PM, Graham Vincent wrote:
> I would be checking the +/- 12 volt supply voltages on the RS232 chips. If you have low voltage or 1 voltage missing the RS232 signal becomes more susceptible to interference. Also if the RS232 chip is a MAX232 the capacitors maybe dry or if the 5 volt supply is low the chip won't generate the 12 v.
> As far as a filter if nothing has changed lately I doubt a filter is going to fix what could be a power problem or a problem on the circuit board .
> 
> Graham Vincent
> Vintron Electronics Ltd
> 
> Ph. 03 3488454
> 
> 
> -----Original Message-----
> From: Chchrobotics <chchrobotics-bounces at lists.ourshack.com> On Behalf Of chchrobotics-request at lists.ourshack.com
> Sent: Tuesday, 25 October 2022 11:55 AM
> To: chchrobotics at lists.ourshack.com
> Subject: Chchrobotics Digest, Vol 181, Issue 7
> 
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> Today's Topics:
> 
>     1. RS232 FILTER (Marshland Engineering)
>     2. Re: RS232 FILTER (Volker Kuhlmann)
>     3. Re: RS232 FILTER (Tokala)
>     4. Re: RS232 FILTER (Daniel Powell)
>     5. Re: RS232 FILTER (Martin Towers)
>     6. Re: RS232 FILTER (Mark Atherton)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 25 Oct 2022 10:31:57 +1300
> From: "Marshland Engineering" <marshland at marshland.co.nz>
> To: chchrobotics at lists.ourshack.com
> Subject: [chbot] RS232 FILTER
> Message-ID: <565175952904364032 at marshland.co.nz>
> Content-Type: text/plain; charset=utf-8
> 
> I have a CNC mill with a RS232 port. If I leave the cable connected to the pendant, any spike in the workshop upsets the CNC control. Turing some things on or welding etc. It is 40 years old so the internal caps may be a bit dogy.
> I was wondering where I could find a filter off the shelf (too many other projects to make new) that I can put in the line. Maybe something I can easily modify. It only works at 9600 baud so low bandwidth.
> 
> Cheers Wallace
> 
> 
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Tue, 25 Oct 2022 10:39:59 +1300
> From: Volker Kuhlmann <list57 at top.geek.nz>
> To: Christchurch Robotics <chchrobotics at lists.ourshack.com>
> Subject: Re: [chbot] RS232 FILTER
> Message-ID: <20221024213959.GA24773 at top.geek.nz>
> Content-Type: text/plain; charset=us-ascii
> 
>> I have a CNC mill with a RS232 port. If I leave the cable connected to
>> the pendant, any spike in the workshop upsets the CNC control. Turing
>> some things
> 
> Weren't there RS232 opto-isolators around back in those days? Or what were they called exactly?
> 
> Volker
> 
> --
> Volker Kuhlmann
> http://volker.top.geek.nz/	Please do not CC list postings to me.
> 
> 
> 
> ------------------------------
> 
> Message: 3
> Date: Mon, 24 Oct 2022 21:42:03 +0000
> From: Tokala <tokalanz at protonmail.com>
> To: marshland at marshland.co.nz, chchrobotics at lists.ourshack.com
> Subject: Re: [chbot] RS232 FILTER
> Message-ID:
> 	<XiIIArw1OHoyoyjWEmGsRlE32WyNsC2x7BguP4HQWVqYiU-ep_QUJ-Z6sENep1BtBmhX7qYZ552f-DtbLdHzCu68FHuwtHHrmjs79dvJjNs=@protonmail.com>
> 	
> Content-Type: text/plain; charset="utf-8"
> 
> Maybe look at RS485. It is less susceptible to noise as it uses the difference in the voltage over the cable e.i. it moves with the noise.
> 
> https://www.seeedstudio.com/blog/2019/12/06/what-is-rs485-and-its-difference-between-rs232/#:~:text=RS232%20is%20more%20than%20able,RS485%20transmits%20at%20100Kb%2Fs.
> 
> RS485 is the industry standard for low speed comms in noise environments.
> 
> Sent from Proton Mail mobile
> 
> -------- Original Message --------
> On 25 Oct 2022, 10:31, Marshland Engineering wrote:
> 
>> I have a CNC mill with a RS232 port. If I leave the cable connected to the pendant, any spike in the workshop upsets the CNC control. Turing some things on or welding etc. It is 40 years old so the internal caps may be a bit dogy. I was wondering where I could find a filter off the shelf (too many other projects to make new) that I can put in the line. Maybe something I can easily modify. It only works at 9600 baud so low bandwidth. Cheers Wallace _______________________________________________ Chchrobotics mailing list Chchrobotics at lists.ourshack.com https://lists.ourshack.com/mailman/listinfo/chchrobotics Mail Archives: http://lists.ourshack.com/pipermail/chchrobotics/ Meetings usually 3rd Monday each month. See http://kiwibots.org for venue, directions and dates. When replying, please edit your Subject line to reflect new subjects.
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> ------------------------------
> 
> Message: 4
> Date: Mon, 24 Oct 2022 22:26:13 +0000
> From: Daniel Powell <danielvieway at hotmail.com>
> To: "marshland at marshland.co.nz" <marshland at marshland.co.nz>,
> 	Christchurch Robotics <chchrobotics at lists.ourshack.com>
> Subject: Re: [chbot] RS232 FILTER
> Message-ID:
> 	<SYBP282MB3685E884BDA1D13DC123EF91D12E9 at SYBP282MB3685.AUSP282.PROD.OUTLOOK.COM>
> 	
> Content-Type: text/plain; charset="us-ascii"
> 
> I gather you are running a shielded cable with a shield earth?
> 
> My only other suggestion is Opto isolation. Although I believe it won't do any signal conditioning and may be an issue with dropped serial signalling.
> 
> https://nz.element14.com/advantech/bb-9spop2/rs232-optical-isolator-2-5kv-115/dp/3523130?gclid=CjwKCAjw79iaBhAJEiwAPYwoCCn2X7oTS1D2glv_-y9x8ErIYW0aUk-PdOwixUXsvDmsBsU3ryasYRoCnH4QAvD_BwE&CMP=KNC-GNZ-SHOPPING-PMAX-3523130
> 
> There are some $10 versions on aliexpress.
> 
> Cheers,
> Daniel.
> 
> -----Original Message-----
> From: Chchrobotics <chchrobotics-bounces at lists.ourshack.com> On Behalf Of Marshland Engineering
> Sent: Tuesday, 25 October 2022 10:32 AM
> To: chchrobotics at lists.ourshack.com
> Subject: [chbot] RS232 FILTER
> 
> I have a CNC mill with a RS232 port. If I leave the cable connected to the pendant, any spike in the workshop upsets the CNC control. Turing some things on or welding etc. It is 40 years old so the internal caps may be a bit dogy.
> I was wondering where I could find a filter off the shelf (too many other projects to make new) that I can put in the line. Maybe something I can easily modify. It only works at 9600 baud so low bandwidth.
> 
> Cheers Wallace
> 
> 
> _______________________________________________
> Chchrobotics mailing list Chchrobotics at lists.ourshack.com
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> 
> ------------------------------
> 
> Message: 5
> Date: Tue, 25 Oct 2022 11:39:03 +1300
> From: Martin Towers <tinytowers at xtra.co.nz>
> To: marshland at marshland.co.nz, Christchurch Robotics
> 	<chchrobotics at lists.ourshack.com>
> Subject: Re: [chbot] RS232 FILTER
> Message-ID:
> 	<d8a0af319d5b9acaa9b9436a664514d3edfd613b.camel at xtra.co.nz>
> Content-Type: text/plain; charset="UTF-8"
> 
> Is the RS232 directly involved in the CNC control.
> If simply plugging in the RS232 disrupts the CNC then you have an earth
> loop or an earth fault.
> 
> Martin
> 
> 
> -----Original Message-----
> From: Marshland Engineering <marshland at marshland.co.nz>
> Reply-To: marshland at marshland.co.nz, Christchurch Robotics
> <chchrobotics at lists.ourshack.com>
> To: chchrobotics at lists.ourshack.com
> Subject: [chbot] RS232 FILTER
> Date: Tue, 25 Oct 2022 10:31:57 +1300
> 
> I have a CNC mill with a RS232 port. If I leave the cable connected to
> the
> pendant, any spike in the workshop upsets the CNC control. Turing some
> things
> on or welding etc. It is 40 years old so the internal caps may be a bit
> dogy.
> I was wondering where I could find a filter off the shelf (too many
> other
> projects to make new) that I can put in the line. Maybe something I can
> easily
> modify. It only works at 9600 baud so low bandwidth.
> 
> Cheers Wallace
> 
> 
> _______________________________________________
> Chchrobotics mailing list Chchrobotics at lists.ourshack.com
> https://lists.ourshack.com/mailman/listinfo/chchrobotics
> Mail Archives: http://lists.ourshack.com/pipermail/chchrobotics/
> Meetings usually 3rd Monday each month. See http://kiwibots.org for
> venue, directions and dates.
> When replying, please edit your Subject line to reflect new subjects.
> 
> 
> 
> 
> ------------------------------
> 
> Message: 6
> Date: Tue, 25 Oct 2022 11:54:57 +1300
> From: Mark Atherton <markaren1 at xtra.co.nz>
> To: chchrobotics at lists.ourshack.com
> Subject: Re: [chbot] RS232 FILTER
> Message-ID: <930ced69-b7c1-deef-73f8-1bdce5c85059 at xtra.co.nz>
> Content-Type: text/plain; charset=utf-8; format=flowed
> 
> Is this a new phenomenon, or has it only recently become a problem ?
> 
> On 25/10/2022 10:31 AM, Marshland Engineering wrote:
>> I have a CNC mill with a RS232 port. If I leave the cable connected to the
>> pendant, any spike in the workshop upsets the CNC control. Turing some things
>> on or welding etc. It is 40 years old so the internal caps may be a bit dogy.
>> I was wondering where I could find a filter off the shelf (too many other
>> projects to make new) that I can put in the line. Maybe something I can easily
>> modify. It only works at 9600 baud so low bandwidth.
>>
>> Cheers Wallace
>>
>>
>> _______________________________________________
>> Chchrobotics mailing list Chchrobotics at lists.ourshack.com
>> https://lists.ourshack.com/mailman/listinfo/chchrobotics
>> Mail Archives: http://lists.ourshack.com/pipermail/chchrobotics/
>> Meetings usually 3rd Monday each month. See http://kiwibots.org for venue, directions and dates.
>> When replying, please edit your Subject line to reflect new subjects.
>>
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