RJ-45 for instrument interface

Started by Steve Wilson March 12, 2018
Since modern computers have no serial or parallel interfaces, the old GPIB 
and RS-232 interfaces are obsolete. There have been discussions about other 
interfaces such as HDMI, but the connector is a bit large.

Consider a setup with a controller connected to the LAN. It may need to 
connect to several or dozens of separate boxes for measurement and control 
functions. Is it a good idea to use RJ-45 for these interfaces also?

The connectors are small, locking, bidirectional, high speed, cable length 
up to 300m, very inexpensive, readily available, and have sufficient pins 
for most needs.

https://en.wikipedia.org/wiki/Modular_connector

The RJ-45 pinouts are well defined and can probably be used as is. One 
issue is with POE, power over ethernet. The voltage applied can be 48V, 
which could destroy most electronics if not controlled. The spec says it 
can only be applied if there is a proper handshake between source and load, 
but that could go awry.

The cables can be double-shielded and come in various lengths and colors. 
Here are some examples:

"When a regular shield is not enough, L-com's exclusive double-shielded 
SF/UTP patch cables are ideal. Category 6 tested, these cables use L-com's 
superior shielding to drastically reduce EMI/RFI interference using a 100% 
foil plus a 65% braid shield. The Low Smoke Zero Halogen jacket allows this 
industrial patch cable to meet today's environmental and safety 
requirements. With 26 AWG stranded conductors, this cable is flexible and 
easy to install even in tight spaces. We stock in full lengths up to 100 
feet so that equipment runs can be pulled directly and simply plugged into 
either end."

https://tinyurl.com/pf3p4xg

"Tera Grand - Premium CAT7 Double Shielded 10 Gigabit 600MHz Ethernet Patch 
Cable for Modem Router LAN Network - Built with Gold Plated & Shielded RJ45 
Connectors, 3 Feet White"

https://tinyurl.com/ya472pcr

"Cat 7 Shielded Ethernet Cable 5 ft 6 Pack ( Highest Speed Cable ) Cat7 
Flat Ethernet Patch Cables - Internet Cable for Modem, Router, LAN, 
Computer - Compatible with Cat 5e, Cat 6 Network"

https://tinyurl.com/y7sfsx9w

What are your thoughts?
On 03/12/2018 08:56 AM, Steve Wilson wrote:
> Since modern computers have no serial or parallel interfaces, the old GPIB > and RS-232 interfaces are obsolete. There have been discussions about other > interfaces such as HDMI, but the connector is a bit large. > > Consider a setup with a controller connected to the LAN. It may need to > connect to several or dozens of separate boxes for measurement and control > functions. Is it a good idea to use RJ-45 for these interfaces also? > > The connectors are small, locking, bidirectional, high speed, cable length > up to 300m, very inexpensive, readily available, and have sufficient pins > for most needs. > > https://en.wikipedia.org/wiki/Modular_connector > > The RJ-45 pinouts are well defined and can probably be used as is. One > issue is with POE, power over ethernet. The voltage applied can be 48V, > which could destroy most electronics if not controlled. The spec says it > can only be applied if there is a proper handshake between source and load, > but that could go awry. > > The cables can be double-shielded and come in various lengths and colors. > Here are some examples: > > "When a regular shield is not enough, L-com's exclusive double-shielded > SF/UTP patch cables are ideal. Category 6 tested, these cables use L-com's > superior shielding to drastically reduce EMI/RFI interference using a 100% > foil plus a 65% braid shield. The Low Smoke Zero Halogen jacket allows this > industrial patch cable to meet today's environmental and safety > requirements. With 26 AWG stranded conductors, this cable is flexible and > easy to install even in tight spaces. We stock in full lengths up to 100 > feet so that equipment runs can be pulled directly and simply plugged into > either end." > > https://tinyurl.com/pf3p4xg > > "Tera Grand - Premium CAT7 Double Shielded 10 Gigabit 600MHz Ethernet Patch > Cable for Modem Router LAN Network - Built with Gold Plated & Shielded RJ45 > Connectors, 3 Feet White" > > https://tinyurl.com/ya472pcr > > "Cat 7 Shielded Ethernet Cable 5 ft 6 Pack ( Highest Speed Cable ) Cat7 > Flat Ethernet Patch Cables - Internet Cable for Modem, Router, LAN, > Computer - Compatible with Cat 5e, Cat 6 Network" > > https://tinyurl.com/y7sfsx9w > > What are your thoughts? >
What do you actually want to accomplish? I's be very unlikely to use an RJ-45 for anything but Ethernet, myself. Most newer instruments have Ethernet connectivity out of the box, and older ones can be controlled via e.g. a Prologix GPIB-Ethernet box. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
On Mar 12, 2018, Steve Wilson wrote
(in article<XnsA8A35AE053D3Eidtokenpost@69.16.179.23>):

> Since modern computers have no serial or parallel interfaces, the old GPIB > and RS-232 interfaces are obsolete. There have been discussions about other > interfaces such as HDMI, but the connector is a bit large. > > Consider a setup with a controller connected to the LAN. It may need to > connect to several or dozens of separate boxes for measurement and control > functions. Is it a good idea to use RJ-45 for these interfaces also? > > The connectors are small, locking, bidirectional, high speed, cable length > up to 300m, very inexpensive, readily available, and have sufficient pins > for most needs. > > https://en.wikipedia.org/wiki/Modular_connector > > The RJ-45 pinouts are well defined and can probably be used as is. One > issue is with POE, power over ethernet. The voltage applied can be 48V, > which could destroy most electronics if not controlled. The spec says it > can only be applied if there is a proper handshake between source and load, > but that could go awry. > > The cables can be double-shielded and come in various lengths and colors. > Here are some examples: > > "When a regular shield is not enough, L-com's exclusive double-shielded > SF/UTP patch cables are ideal. Category 6 tested, these cables use L-com's > superior shielding to drastically reduce EMI/RFI interference using a 100% > foil plus a 65% braid shield. The Low Smoke Zero Halogen jacket allows this > industrial patch cable to meet today's environmental and safety > requirements. With 26 AWG stranded conductors, this cable is flexible and > easy to install even in tight spaces. We stock in full lengths up to 100 > feet so that equipment runs can be pulled directly and simply plugged into > either end." > > https://tinyurl.com/pf3p4xg > > "Tera Grand - Premium CAT7 Double Shielded 10 Gigabit 600MHz Ethernet Patch > Cable for Modem Router LAN Network - Built with Gold Plated & Shielded RJ45 > Connectors, 3 Feet White" > > https://tinyurl.com/ya472pcr > > "Cat 7 Shielded Ethernet Cable 5 ft 6 Pack ( Highest Speed Cable ) Cat7 > Flat Ethernet Patch Cables - Internet Cable for Modem, Router, LAN, > Computer - Compatible with Cat 5e, Cat 6 Network" > > https://tinyurl.com/y7sfsx9w > > What are your thoughts?
I&rsquo;d run RS-485/422 over Cat 6 with RJ-45 connectors. Assume that accidental connection with anything using RJ-45 connectors will be common. Power over this cable should follow PoE standards, for safety, and vailability of hardware. It took 802.3 a lot of effort to develop PoE in detail, and there is no percentage in trying to replicate that effort. Joe Gwinn
On Mon, 12 Mar 2018 12:56:00 GMT, Steve Wilson <no@spam.com> wrote:

>Since modern computers have no serial or parallel interfaces, the old GPIB >and RS-232 interfaces are obsolete. There have been discussions about other >interfaces such as HDMI, but the connector is a bit large. > >Consider a setup with a controller connected to the LAN. It may need to >connect to several or dozens of separate boxes for measurement and control >functions. Is it a good idea to use RJ-45 for these interfaces also? > >The connectors are small, locking, bidirectional, high speed, cable length >up to 300m, very inexpensive, readily available, and have sufficient pins >for most needs. > >https://en.wikipedia.org/wiki/Modular_connector > >The RJ-45 pinouts are well defined and can probably be used as is. One >issue is with POE, power over ethernet. The voltage applied can be 48V, >which could destroy most electronics if not controlled. The spec says it >can only be applied if there is a proper handshake between source and load, >but that could go awry. > >The cables can be double-shielded and come in various lengths and colors. >Here are some examples: > >"When a regular shield is not enough, L-com's exclusive double-shielded >SF/UTP patch cables are ideal. Category 6 tested, these cables use L-com's >superior shielding to drastically reduce EMI/RFI interference using a 100% >foil plus a 65% braid shield. The Low Smoke Zero Halogen jacket allows this >industrial patch cable to meet today's environmental and safety >requirements. With 26 AWG stranded conductors, this cable is flexible and >easy to install even in tight spaces. We stock in full lengths up to 100 >feet so that equipment runs can be pulled directly and simply plugged into >either end." > >https://tinyurl.com/pf3p4xg > >"Tera Grand - Premium CAT7 Double Shielded 10 Gigabit 600MHz Ethernet Patch >Cable for Modem Router LAN Network - Built with Gold Plated & Shielded RJ45 >Connectors, 3 Feet White" > >https://tinyurl.com/ya472pcr > >"Cat 7 Shielded Ethernet Cable 5 ft 6 Pack ( Highest Speed Cable ) Cat7 >Flat Ethernet Patch Cables - Internet Cable for Modem, Router, LAN, >Computer - Compatible with Cat 5e, Cat 6 Network" > >https://tinyurl.com/y7sfsx9w > >What are your thoughts?
Putting an FTDI USB-to-serial chip on your board is the easiest way to interface a small instrument. Your internal uP sees a serial interface, and the control computer sees a usb-serial chip. Most OS's are familiar with the FTDI chip. It's equivalent to burying a USB-serial dongle inside your gadget. Use USB hubs and cables. If you need to go long distances, go Ethernet but that's a bit more work. -- John Larkin Highland Technology, Inc lunatic fringe electronics
On Monday, March 12, 2018 at 6:56:05 AM UTC-6, Steve Wilson wrote:
> Since modern computers have no serial or parallel interfaces, the old GPIB > and RS-232 interfaces are obsolete. There have been discussions about other > interfaces such as HDMI, but the connector is a bit large. > > Consider a setup with a controller connected to the LAN. It may need to > connect to several or dozens of separate boxes for measurement and control > functions. Is it a good idea to use RJ-45 for these interfaces also? > > The connectors are small, locking, bidirectional, high speed, cable length > up to 300m, very inexpensive, readily available, and have sufficient pins > for most needs. > > https://en.wikipedia.org/wiki/Modular_connector > > The RJ-45 pinouts are well defined and can probably be used as is. One > issue is with POE, power over ethernet. The voltage applied can be 48V, > which could destroy most electronics if not controlled. The spec says it > can only be applied if there is a proper handshake between source and load, > but that could go awry. > > The cables can be double-shielded and come in various lengths and colors. > Here are some examples: > > "When a regular shield is not enough, L-com's exclusive double-shielded > SF/UTP patch cables are ideal. Category 6 tested, these cables use L-com's > superior shielding to drastically reduce EMI/RFI interference using a 100% > foil plus a 65% braid shield. The Low Smoke Zero Halogen jacket allows this > industrial patch cable to meet today's environmental and safety > requirements. With 26 AWG stranded conductors, this cable is flexible and > easy to install even in tight spaces. We stock in full lengths up to 100 > feet so that equipment runs can be pulled directly and simply plugged into > either end." > > https://tinyurl.com/pf3p4xg > > "Tera Grand - Premium CAT7 Double Shielded 10 Gigabit 600MHz Ethernet Patch > Cable for Modem Router LAN Network - Built with Gold Plated & Shielded RJ45 > Connectors, 3 Feet White" > > https://tinyurl.com/ya472pcr > > "Cat 7 Shielded Ethernet Cable 5 ft 6 Pack ( Highest Speed Cable ) Cat7 > Flat Ethernet Patch Cables - Internet Cable for Modem, Router, LAN, > Computer - Compatible with Cat 5e, Cat 6 Network" > > https://tinyurl.com/y7sfsx9w > > What are your thoughts?
We used to use them in one of our main instruments. The two main reasons we stopped were: 1) Customers do amazingly stupid things. They WILL plug inappropriate things into those ports. 2) Too often we needed to feed 5V power at up to an amp through them, and the voltage drop was unacceptable.
On 03/12/2018 10:59 AM, John Larkin wrote:
> On Mon, 12 Mar 2018 12:56:00 GMT, Steve Wilson <no@spam.com> wrote: > >> Since modern computers have no serial or parallel interfaces, the old GPIB >> and RS-232 interfaces are obsolete. There have been discussions about other >> interfaces such as HDMI, but the connector is a bit large. >> >> Consider a setup with a controller connected to the LAN. It may need to >> connect to several or dozens of separate boxes for measurement and control >> functions. Is it a good idea to use RJ-45 for these interfaces also? >> >> The connectors are small, locking, bidirectional, high speed, cable length >> up to 300m, very inexpensive, readily available, and have sufficient pins >> for most needs. >> >> https://en.wikipedia.org/wiki/Modular_connector >> >> The RJ-45 pinouts are well defined and can probably be used as is. One >> issue is with POE, power over ethernet. The voltage applied can be 48V, >> which could destroy most electronics if not controlled. The spec says it >> can only be applied if there is a proper handshake between source and load, >> but that could go awry. >> >> The cables can be double-shielded and come in various lengths and colors. >> Here are some examples: >> >> "When a regular shield is not enough, L-com's exclusive double-shielded >> SF/UTP patch cables are ideal. Category 6 tested, these cables use L-com's >> superior shielding to drastically reduce EMI/RFI interference using a 100% >> foil plus a 65% braid shield. The Low Smoke Zero Halogen jacket allows this >> industrial patch cable to meet today's environmental and safety >> requirements. With 26 AWG stranded conductors, this cable is flexible and >> easy to install even in tight spaces. We stock in full lengths up to 100 >> feet so that equipment runs can be pulled directly and simply plugged into >> either end." >> >> https://tinyurl.com/pf3p4xg >> >> "Tera Grand - Premium CAT7 Double Shielded 10 Gigabit 600MHz Ethernet Patch >> Cable for Modem Router LAN Network - Built with Gold Plated & Shielded RJ45 >> Connectors, 3 Feet White" >> >> https://tinyurl.com/ya472pcr >> >> "Cat 7 Shielded Ethernet Cable 5 ft 6 Pack ( Highest Speed Cable ) Cat7 >> Flat Ethernet Patch Cables - Internet Cable for Modem, Router, LAN, >> Computer - Compatible with Cat 5e, Cat 6 Network" >> >> https://tinyurl.com/y7sfsx9w >> >> What are your thoughts? > > Putting an FTDI USB-to-serial chip on your board is the easiest way to > interface a small instrument. Your internal uP sees a serial > interface, and the control computer sees a usb-serial chip. Most OS's > are familiar with the FTDI chip. > > It's equivalent to burying a USB-serial dongle inside your gadget. Use > USB hubs and cables. > > If you need to go long distances, go Ethernet but that's a bit more > work.
We use FTDIs too. The problem in Windows is that you don't know how the ports are going to enumerate, so it's hard to use multiple instruments. The Prologix GPIB-Ethernet can run a few GPIB instruments, but not a whole rack-full. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
On 12/03/2018 12:56, Steve Wilson wrote:
> Since modern computers have no serial or parallel interfaces, the old GPIB > and RS-232 interfaces are obsolete. There have been discussions about other > interfaces such as HDMI, but the connector is a bit large. > > Consider a setup with a controller connected to the LAN. It may need to > connect to several or dozens of separate boxes for measurement and control > functions. Is it a good idea to use RJ-45 for these interfaces also? >
Depends.... We inplemented a similar scheme but had full control over the PC controlling software and hardware and the same for the peripheral devices... PC had a 5 byte packet out and a 3 byte packet return. Each peripheral had its own ID which was part of the 5 bytes.. ID + command + parameter 1 + parameter 2 + crc. A responding peripheral sent back data1 + data2 + crc.All at 115K baud and a few hundred metres. Your issue will be POE..... CAT5 can't carry high currents. High voltages and low currents is the only way but beware of shorts from power to data !!! --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
On Mon, 12 Mar 2018 11:26:56 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 03/12/2018 10:59 AM, John Larkin wrote: >> On Mon, 12 Mar 2018 12:56:00 GMT, Steve Wilson <no@spam.com> wrote: >> >>> Since modern computers have no serial or parallel interfaces, the old GPIB >>> and RS-232 interfaces are obsolete. There have been discussions about other >>> interfaces such as HDMI, but the connector is a bit large. >>> >>> Consider a setup with a controller connected to the LAN. It may need to >>> connect to several or dozens of separate boxes for measurement and control >>> functions. Is it a good idea to use RJ-45 for these interfaces also? >>> >>> The connectors are small, locking, bidirectional, high speed, cable length >>> up to 300m, very inexpensive, readily available, and have sufficient pins >>> for most needs. >>> >>> https://en.wikipedia.org/wiki/Modular_connector >>> >>> The RJ-45 pinouts are well defined and can probably be used as is. One >>> issue is with POE, power over ethernet. The voltage applied can be 48V, >>> which could destroy most electronics if not controlled. The spec says it >>> can only be applied if there is a proper handshake between source and load, >>> but that could go awry. >>> >>> The cables can be double-shielded and come in various lengths and colors. >>> Here are some examples: >>> >>> "When a regular shield is not enough, L-com's exclusive double-shielded >>> SF/UTP patch cables are ideal. Category 6 tested, these cables use L-com's >>> superior shielding to drastically reduce EMI/RFI interference using a 100% >>> foil plus a 65% braid shield. The Low Smoke Zero Halogen jacket allows this >>> industrial patch cable to meet today's environmental and safety >>> requirements. With 26 AWG stranded conductors, this cable is flexible and >>> easy to install even in tight spaces. We stock in full lengths up to 100 >>> feet so that equipment runs can be pulled directly and simply plugged into >>> either end." >>> >>> https://tinyurl.com/pf3p4xg >>> >>> "Tera Grand - Premium CAT7 Double Shielded 10 Gigabit 600MHz Ethernet Patch >>> Cable for Modem Router LAN Network - Built with Gold Plated & Shielded RJ45 >>> Connectors, 3 Feet White" >>> >>> https://tinyurl.com/ya472pcr >>> >>> "Cat 7 Shielded Ethernet Cable 5 ft 6 Pack ( Highest Speed Cable ) Cat7 >>> Flat Ethernet Patch Cables - Internet Cable for Modem, Router, LAN, >>> Computer - Compatible with Cat 5e, Cat 6 Network" >>> >>> https://tinyurl.com/y7sfsx9w >>> >>> What are your thoughts? >> >> Putting an FTDI USB-to-serial chip on your board is the easiest way to >> interface a small instrument. Your internal uP sees a serial >> interface, and the control computer sees a usb-serial chip. Most OS's >> are familiar with the FTDI chip. >> >> It's equivalent to burying a USB-serial dongle inside your gadget. Use >> USB hubs and cables. >> >> If you need to go long distances, go Ethernet but that's a bit more >> work. > >We use FTDIs too. The problem in Windows is that you don't know how the >ports are going to enumerate, so it's hard to use multiple instruments.
All of our gadgets ID themselves with model number and serial number, so an app can scan all the serial ports, looking for devices. That is a mild nuisance, but it works.
> >The Prologix GPIB-Ethernet can run a few GPIB instruments, but not a >whole rack-full.
Do people still make instruments with GPIB? It's getting old. We use Ethernet a lot too, both inside gadgets running Linux and bare metal, with "discrete" uPs and with SOCs. There are learning curves, but it becomes routine after the first one. We recently persuaded the GbE interface of a ZYNQ to talk to a 100 Mbit PHY. That saved a lot of balls and long PCB traces. -- John Larkin Highland Technology, Inc lunatic fringe electronics
On Mon, 12 Mar 2018 12:56:00 GMT, Steve Wilson <no@spam.com> wrote:

>One >issue is with POE, power over ethernet. The voltage applied can be 48V, >which could destroy most electronics if not controlled. The spec says it >can only be applied if there is a proper handshake between source and load, >but that could go awry.
If you use an 802.3af, 802.3at, or 802.3bt interface for the power, it won't blow anything up. <https://en.wikipedia.org/wiki/Power_over_Ethernet> If you're pushing gigabit ethernet through the cable, it's about the only way to do PoE. Note that there are several different types of PoE, some of which are incompatible even though the RJ45 connector fits. The handshake process is sufficiently complexicated that it would take a minor miracle or a very unlucky customer to fool the power injector into delivering full power. From my limited experience with various cheap PoE switches and phones, wrong injector type, weird midspan devices, insufficient injector power, rotten CAT5e crimp connections, creative pinouts, and AC power line glitches are the real problems, all of which will inhibit the injector from producing power. Methinks you're safe with PoE. My guess(tm), based up not knowing your application or how much power you need to deliver, is that the price of a PoE system is likely to be the real problem. Good luck. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
On 03/12/2018 12:00 PM, John Larkin wrote:
> On Mon, 12 Mar 2018 11:26:56 -0400, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> On 03/12/2018 10:59 AM, John Larkin wrote: >>> On Mon, 12 Mar 2018 12:56:00 GMT, Steve Wilson <no@spam.com> wrote: >>> >>>> Since modern computers have no serial or parallel interfaces, the old GPIB >>>> and RS-232 interfaces are obsolete. There have been discussions about other >>>> interfaces such as HDMI, but the connector is a bit large. >>>> >>>> Consider a setup with a controller connected to the LAN. It may need to >>>> connect to several or dozens of separate boxes for measurement and control >>>> functions. Is it a good idea to use RJ-45 for these interfaces also? >>>> >>>> The connectors are small, locking, bidirectional, high speed, cable length >>>> up to 300m, very inexpensive, readily available, and have sufficient pins >>>> for most needs. >>>> >>>> https://en.wikipedia.org/wiki/Modular_connector >>>> >>>> The RJ-45 pinouts are well defined and can probably be used as is. One >>>> issue is with POE, power over ethernet. The voltage applied can be 48V, >>>> which could destroy most electronics if not controlled. The spec says it >>>> can only be applied if there is a proper handshake between source and load, >>>> but that could go awry. >>>> >>>> The cables can be double-shielded and come in various lengths and colors. >>>> Here are some examples: >>>> >>>> "When a regular shield is not enough, L-com's exclusive double-shielded >>>> SF/UTP patch cables are ideal. Category 6 tested, these cables use L-com's >>>> superior shielding to drastically reduce EMI/RFI interference using a 100% >>>> foil plus a 65% braid shield. The Low Smoke Zero Halogen jacket allows this >>>> industrial patch cable to meet today's environmental and safety >>>> requirements. With 26 AWG stranded conductors, this cable is flexible and >>>> easy to install even in tight spaces. We stock in full lengths up to 100 >>>> feet so that equipment runs can be pulled directly and simply plugged into >>>> either end." >>>> >>>> https://tinyurl.com/pf3p4xg >>>> >>>> "Tera Grand - Premium CAT7 Double Shielded 10 Gigabit 600MHz Ethernet Patch >>>> Cable for Modem Router LAN Network - Built with Gold Plated & Shielded RJ45 >>>> Connectors, 3 Feet White" >>>> >>>> https://tinyurl.com/ya472pcr >>>> >>>> "Cat 7 Shielded Ethernet Cable 5 ft 6 Pack ( Highest Speed Cable ) Cat7 >>>> Flat Ethernet Patch Cables - Internet Cable for Modem, Router, LAN, >>>> Computer - Compatible with Cat 5e, Cat 6 Network" >>>> >>>> https://tinyurl.com/y7sfsx9w >>>> >>>> What are your thoughts? >>> >>> Putting an FTDI USB-to-serial chip on your board is the easiest way to >>> interface a small instrument. Your internal uP sees a serial >>> interface, and the control computer sees a usb-serial chip. Most OS's >>> are familiar with the FTDI chip. >>> >>> It's equivalent to burying a USB-serial dongle inside your gadget. Use >>> USB hubs and cables. >>> >>> If you need to go long distances, go Ethernet but that's a bit more >>> work. >> >> We use FTDIs too. The problem in Windows is that you don't know how the >> ports are going to enumerate, so it's hard to use multiple instruments. > > All of our gadgets ID themselves with model number and serial number, > so an app can scan all the serial ports, looking for devices. That is > a mild nuisance, but it works.
Well, you guys get a gold star then. ;) Not everybody does that, unfortunately.
> >> >> The Prologix GPIB-Ethernet can run a few GPIB instruments, but not a >> whole rack-full. > > Do people still make instruments with GPIB? It's getting old.
Yup. Generally along with Ethernet and/or USB.
> > We use Ethernet a lot too, both inside gadgets running Linux and bare > metal, with "discrete" uPs and with SOCs. There are learning curves, > but it becomes routine after the first one. > > We recently persuaded the GbE interface of a ZYNQ to talk to a 100 > Mbit PHY. That saved a lot of balls and long PCB traces.
I've never actually implemented an Ethernet instrument--most of my stuff is still one-offs and proofs-of-concept. With DFH on full time and more licensing stuff in the works, that may change. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com