✅ C'mon over to realpars.com where you can learn PLC programming faster and easier than you ever thought possible!

==========================

✅ Check out the full blog post over at realpars.com/rs485/ ‎

What is RS232 and What is it used for? realpars.com/rs232/

==========================

Today you will learn about RS 485. If you are familiar with RS232, then you may already know a little bit about it.

Just like it’s older brother RS232, RS485 is a form of serial communication. Think of RS485 as the younger, faster brother of RS232.

What made it such an advancement over RS232 was the fact that it could transmit not only a single device to device transmission, but also a communications bus to connect multiple devices at once.

The configuration and specifications of RS 485 make it faster and extend the range of data transmission.

You aren’t limited to fifty feet of cable like with RS 232. The maximum cable length for RS 485 is typically listed as 1200 meters or about 4000 feet.

==========================

Missed our most recent videos? Watch them here:

realpars.com/plc-manufacturers/

realpars.com/plc-analog-inputs/

realpars.com/servo-motors-advantages/

=============================

To stay up to date with our last videos and more lessons, make sure to subscribe to this YouTube channel:
goo.gl/Y6DRiN

=============================

TWEET THIS VIDEO ctt.ac/c5sT2

=============================

Like us on Facebook: www.facebook.com/therealpars/

Follow us on Twitter: twitter.com/realpars

Follow us on LinkedIn www.linkedin.com/company/realpars

#RealPars #RS485

Comments

    • Caustic Caucasian
      Caustic Caucasian

      If RS-485 can handle up to 32 connected devices, why does the RS-485 port on the Easytouch automation system for a pool freak out when you connect 3 or more???

      about 14 days ago
    • RealPars
      RealPars In reply to Caustic Caucasian

      Many consumer devices are capable of communications using modern protocols, but because they are limited in scope, the processors are not always set up to take full advantage of the power of those protocols. Many times, these consumer products, have artificial limits to their capabilities, such as 2 nodes on RW-485 or other limitations. They figure beyond the main controller, the user would only have two other nodes, such as an automatic chlorinator or a lighting controller. Even in an industrial system, a 32-node configuration would likely bring a controller to its knees from a timing and loading standpoint.

      about 13 days ago
    • Vodka Puschkin
      Vodka Puschkin

      ok i learnd something new. thank you

      about 28 days ago
    • RealPars
      RealPars In reply to Vodka Puschkin

      Great to hear that!

      about 27 days ago
    • Colin Amondson
      Colin Amondson

      The RS485 is a comms that allows control of the IGBT however the VFD input output to the motor is a power system and this is not shown, there is a lot more going on.

      about 1 month ago
    • Colin Amondson
      Colin Amondson In reply to Colin Amondson

      @Scott Sommer I know all that it was confusing to see the line going to the motor in the same colour as the RS 485

      about 1 month ago
    • Scott Sommer
      Scott Sommer In reply to Colin Amondson

      Correct. The purpose of this video is to demonstrate the ability of RS485 to communicate with a VFD. The power connections are not shown. RS485 can be used to send a start signal, a stop signal and a reference (setpoint) speed signal to a VFD that has an RS485 comm port. Other data, like motor status and speed can be sent back to the PLC from the VFD as well using RS485. Profibus is a more advanced protocol for communicating with VFD's and other devices, but at its core, Profibus is based on RS485.

      about 1 month ago
    • benaissa taibi
      benaissa taibi

      Great video thanks

      about 1 month ago
    • longbeachboy57
      longbeachboy57

      You forgot to mention that Interbus, DeviceNet, ProfiBus etc are all clones of RS485 with some extra features...

      about 1 month ago
    • longbeachboy57
      longbeachboy57 In reply to longbeachboy57

      @YoutubeCommentSectionIsCancerous OK. I apologize for commenting. Thanks for your feedback!!!

      about 14 days ago
    • YoutubeCommentSectionIsCancerous
      YoutubeCommentSectionIsCancerous In reply to longbeachboy57

      lol, this is supposed to be an introductory video. You just can't mention everything on the first go

      about 17 days ago
    • mbilu Khelebeni
      mbilu Khelebeni

      Wonderful I really enjoyed it

      about 1 month ago
    • RealPars
      RealPars In reply to mbilu Khelebeni

      Great to hear hat, Mbilu!

      about 1 month ago
    • ayad ayad
      ayad ayad

      Thak you from ...Iraq ...baghdad

      about 1 month ago
    • RealPars
      RealPars In reply to ayad ayad

      You are welcome!

      about 1 month ago
    • Sean Embry
      Sean Embry

      I worked at AmTote International at one point. They provide IT services to legal wagering services for dog, horse, and other Parimutuel wagering and parking systems . They used RS485/RS422 connections to their ticket sales terminals. On one system, Sperry V77 systems were able to issue 90 tickets per second, something that modern systems are hard pressed to match. Transactions were exported to 9 track reel to reel data drives, and most were duplex systems. Some states required a Triplex system.
      Main not working memory was magnetic core, up to 1990. Yeah, kinda gob smacking. 8 Meg of Ram took 2 cabinets 7' tall. They weighed about 1,800 pounds each. Main memory was SD-RAM. Thing of it was, it was almost indestructible. Hit by lighting? Not really an issue for the core system.

      about 1 month ago
    • Damian
      Damian

      Great job ;)

      about 2 months ago
    • RealPars
      RealPars In reply to Damian

      Thank you!

      about 2 months ago
    • Rousbell Juarez
      Rousbell Juarez

      LO MÁS INTERESANTE QUE VI EN LOS VIDEOS DE YOUTUBE

      about 2 months ago
    • RealPars
      RealPars In reply to Rousbell Juarez

      Gracias!

      about 2 months ago
    • Muhammed Ismaeel
      Muhammed Ismaeel

      I'm wondering if the realpars programs that give a distance teaching PLC course with a certificate, I'm from Iraq.

      about 3 months ago
    • RealPars
      RealPars In reply to Muhammed Ismaeel

      We certainly offer the option to purchase our Certification of Completion after completing at least 250 of our video courses. You can find more information about our Certificate through the following link https://bit.ly/2LADnPY

      Let me know if you have any further questions.

      about 2 months ago
    • naveen joseph
      naveen joseph

      thank you

      about 3 months ago
    • RealPars
      RealPars In reply to naveen joseph

      You are very welcome!

      about 3 months ago
    • 공돌TV
      공돌TV

      Wow! This explain is very simple and easy to understand!

      about 3 months ago
    • RealPars
      RealPars In reply to 공돌TV

      Great to hear! Happy learning!

      about 3 months ago
    • Acme Fixer
      Acme Fixer

      This video about RS-485 is limited to the industrial control and it doesn't discuss any of the limitations of RS-485. RS-232 and RS-485 are electrical and mechanical interfaces and do not specify how many devices or what speed the data is sent. The video states there is no standard RS-485 connector but the true RS-485 specifications state the type of connector and the number of pins, and anything that does not conform to the specifications is not RS-485. IIRC the original specifications did *not* use a DB-9 connector. So this video leaves out a lot of information that may be needed for an accurate explanation of the RS-485 interface. Thanks for the limited video.

      about 3 months ago
    • David Moran
      David Moran In reply to Acme Fixer

      You forget that the RS in RS-x is 'Recommended' Standard and there is no connector specification. Additionally you as well as the content provider stated DB 9 what was shown is a DE 9. Unfortunately the content provider did not comment on the most often forgotten ground, 2 wire, as shown, is actually 2 wire plus ground, and the 4 wire systems are actually 4 wire plus ground. On smaller systems as shown, were the equipment shares the same earth connection, although there is more noise, will generally function as intended. When doing camera and control over large areas requiring fiber optic transmission between nodes, this becomes very relevant, I used to design networks that covered entire states, as well as border protection for other countries.

      about 3 months ago
    • Adriano Me
      Adriano Me

      Very helpful, Thank you very much Sir.

      about 3 months ago
    • RealPars
      RealPars In reply to Adriano Me

      Great to hear! You are very welcome.

      about 3 months ago
    • Rupin Chheda
      Rupin Chheda

      The range of the bus is higher and it can support faster speeds because of Differential Signalling. The signal sent across the bus is not referenced to ground, but to each other. The difference in signal levels between the bus wires determines a 1 or a 0. Noise if present pushes both the wires up or down in the same magnitude, thereby maintaining the difference in signal levels. USB is a faster bus partly because of differential signalling.

      about 3 months ago
    • Oat lord
      Oat lord

      Isn't ethernet better at controlling devices than 485? Or is this older tech?

      about 3 months ago
    • David Moran
      David Moran In reply to Oat lord

      ​@Oat lord As far a ease of install, Yes Ethernet would be easier due to the standardized wiring and connectors. However the software on the endpoint devices would be more involved and require additional memory adding to cost. This is one of the things that I worked on with one state DOT, standardizing the wiring scheme as there 64 ways you could wire the ends, but only 1 works properly and most of the others will bring the entire network down. The DOT had camera control, traffic light timing and control to/from the controllers, bridge fire alarm monitoring and alarm contacts on 4 fiber optic cables multiplexing video and data to cover the entire state. There are devices to carry RS485 over Ethernet, but again adding cost.

      about 3 months ago
    • Oat lord
      Oat lord In reply to Oat lord

      @David Moran You're way more knowledgeable than me obviously, but I meant it from an ease of installation and wide industry usage of the ethernet standard and tcpip stack. I was asking a question more than trying to make a statement if that makes sense.

      about 3 months ago
    • David Moran
      David Moran In reply to Oat lord

      The better comes from the software the layer 1 is just the methodology used to transfer. Ethernet uses Manchester Bi-Phase which actually requires more transitions per bit.

      about 3 months ago
    • brencostigan
      brencostigan

      RS-485 is more accurately described as the grown up big brother of RS-422. It’s not fair to compare it directly to RS-232. The reason RS-485 still enjoys massive usage in industrial applications is due to the range of physical layer implementations. As stated in the video it supports multi-drop as opposed to just point-to-point like RS-232. However, it can be used in full or half duplex modes. This means that a station on a RS-485 bus can simultaneously transmit and receive data at the same time.
      RS-485 can be transmitted over both optical and copper physical layers. The optical implementations support dual redundant optical rings which are very robust. Both optical and copper layer repeaters mean that each copper segment can be extended to then support up to 255 node addresses (0 to 254) for the overall network. The actual protocols that run over this RS-485 physical layer are also very lean and efficient in data throughput. Profibus-DP is one example, but please note that Profibus does make a number of changes to the underlying RS-485 physical layer rules (capacitance and inductance limits, etc). Profibus-DP can run up to 12Mbps. Unfortunately, RS-485 is probably the single most misunderstood transmission technique due to a lack of understanding about bus termination requirements and correct screen connections.

      about 3 months ago
    • brencostigan
      brencostigan In reply to brencostigan

      David Moran

      This flexibility and ability to in effect cascade these different physical layers has also contributed to its longevity and success. RS-485 devices can also be used to replace failed stations in older RS-422 architectures with very little difficulty, although the reverse isn’t always possible. However, you can drop an RS-485 master into an existing RS-422 slave network with no problems.

      about 3 months ago
    • David Moran
      David Moran In reply to brencostigan

      Very good, RS 232, in most configurations, is point to point Where RS 422 is point to multi-point and RS 485 is multi point to multi-point. Where I once worked we made counter rotating, self healing, multi-master ring modems capable of translation from 485 to/from 232 to/from 422.

      about 3 months ago
    • Ardent Dfender
      Ardent Dfender

      I find this useful and until earlier today at work I had never heard of RS485, but I’ve heard of and used a RS232 Cable connection. I also maybe think 🤔 something that could of also being elaborated on in the age of where almost all if not many controllers have a Ethernet connection when and where a RS485 cable could be useful? I’m just junior programmer but do O.P.A.C. Engineering - Operation, Process, Automations Control Engineering. Wear many hats in what I’m doing from one week to next. Two weeks ago was on a RO plant water system startup at a plant site. It was SLC PLC with redundant processor chassis and all Ethernet connected to plc network switch with remote I/O’s. To connect directly to the SLC Processor while system was all online had to connect via RS232 on the SLC Card to Primary and Secondary Processor. As the Ethernet port was in use on both cards connected to network. That’s an example I can think of and recent where having my RS232 to USB on laptop Serial cable came in handy and was good to have. Such an example also could of being more in depth explained with the RS485 cable in various situations. However, still excellent video to educate and the more I now know.

      about 3 months ago
    • RealPars
      RealPars In reply to Ardent Dfender

      Thanks for sharing your thoughts with us!

      about 3 months ago
    • Soylent Green
      Soylent Green

      Why not just use ethernet?

      about 3 months ago
    • john edwards
      john edwards In reply to Soylent Green

      not terribly good in industrial and electrically noisy environs

      about 1 month ago
    • bachelors of trolling degree, 2013
      bachelors of trolling degree, 2013 In reply to Soylent Green

      Ethernet does support a bus topology and can be setup for redundancy. Trust me. I work with it everyday.

      about 3 months ago
    • brencostigan
      brencostigan In reply to Soylent Green

      Also, low cost Ethernet doesn’t support redundant self healing optical rings. You could splice in an FDDI layer into an Ethernet environment to do something similar but at significant cost.
      So it might be easier to ask “what did the Roman’s ever do for us?.....”
      Having said that it is fair to say that Ethernet is being adopted more and more in Industrial communications but Ethernet redundancy is still difficult to realise in cost effective solutions at present. Fault tolerant Ethernet is out there but the capital investment is much higher.

      about 3 months ago
    • Tim Baggett
      Tim Baggett In reply to Soylent Green

      Low cost Ethernet doesn’t go 4000 feet or support a bus topology. But... search Google for “802.3cg”

      about 3 months ago
    • Mohsin Khan
      Mohsin Khan

      sir can i connect load via RS 485

      about 3 months ago
    • RealPars
      RealPars In reply to Mohsin Khan

      If your device has an RS-485 port on it, you can do that.

      about 3 months ago
    • Rakib Hasan
      Rakib Hasan

      Special thanks real pars

      about 3 months ago
    • RealPars
      RealPars In reply to Rakib Hasan

      You are very welcome, Rakib!

      about 3 months ago
    • THIYAGU D
      THIYAGU D

      Thank you rp

      about 5 months ago
    • RealPars
      RealPars In reply to THIYAGU D

      You are welcome!

      about 5 months ago
    • eddahbi eddahbi
      eddahbi eddahbi

      thanks

      about 5 months ago
    • Nick Contabile
      Nick Contabile

      Thank you for the easy to understand flow of this video. It really helped me understand the standard.

      about 6 months ago
    • RealPars
      RealPars In reply to Nick Contabile

      That is perfect Nick! Happy to hear that.

      about 6 months ago
    • Yahya Jaber
      Yahya Jaber

      So RS485 is a physical connection, and on top of it there is the protocol that makes the nodes communicate and control, like modbus, canbus, SCADA...is this correct?
      Thanks.

      about 6 months ago
    • RealPars
      RealPars In reply to Yahya Jaber

      Yes, RS485 is merely a physical (electrical) connection and as you mentioned, some defined protocols such as Modbus, Profibus and so on using it as one of their physical media to make their nodes communicate within the network. Thanks for your question.

      about 6 months ago
    • Civil Yard
      Civil Yard

      Plz, what's the benefits of RS485 for controlling a servo motor with arduino? ?

      about 6 months ago
    • TheHiphopgems
      TheHiphopgems

      Thanks!

      about 6 months ago
    • RealPars
      RealPars In reply to TheHiphopgems

      You are welcome!

      about 6 months ago
    • hemanth 2a7
      hemanth 2a7

      Nice video thank you

      about 7 months ago
    • RealPars
      RealPars In reply to hemanth 2a7

      You are very welcome!

      about 7 months ago
    • mt
      mt

      Brief and useful information about RS-485. Thank you.

      about 7 months ago
    • RealPars
      RealPars In reply to mt

      Great! You're very welcome.

      about 7 months ago