What is RS232 and What is it Used for?

today you'll learn about rs-232 it's a phrase you may hear fairly regularly in industry especially by the older guys hopefully this video will clear some things up for you [Music] before we get into today's video if you love our videos be sure to click the like button below and make sure to click Subscribe and the bell to receive notifications of new real Parrs videos this way you never miss another one what exactly is rs-232 first and foremost it is a form of serial data transmission or simply put it is a form of communication most people simply called it a serial connection at one time it was the most used form of data transmission you'll probably recognize the standard nine pin db9 cable simply put rs-232 transmit signals using a positive voltage for a binary zero and a negative voltage for a binary one but what do the PLC's use rs-232 for PLC's use rs-232 to talk to other modules or even other PLC's these modules can be anything that also uses rs-232 such as operator interface or HMI computers motor controllers or drives a robot or some kind of vision system one important thing to remember if you find yourself using rs-232 devices is that there are actually two different types DTE stands for data terminal equipment a common example of this is a computer DC e stands for data communications equipment an example of DC e is a modem the reason this is important is because to dte or to DCE devices cannot talk to each other without some help this is typically done by using a reverse null modem cable to connect the devices typically our PLC's will be DTE and our devices will be DCE and everything should talk to each other one very common example that many people are probably familiar with is a computer connected to a printer while USB has become the standard rs-232 is still widely used for older printers in the workplace the rs-232 protocol and cable allow the computer to give commands to the printer via a voltage signal the printer then deciphers those commands and completes the print there are a couple of disadvantages of rs-232 one is the speed at which data can be transferred data can be transferred at around 20 kilobytes per second that's pretty slow compared to what people are used to now another issue with rs-232 is that the maximum length of a cable is about 50 feet wire resistance and voltage loops become an issue with cables longer than this this is one reason rs-232 is not used as much as newer technology for remote installations so let's review what we have learned for years rs-232 has been a standard in industry today USB and Ethernet have started to phase out this older serial communication standard however with the help of simple adapters devices can still talk to each other using the new and old standards there are still many manufacturers using rs-232 since it has always been widespread and inexpensive manufacturers may use rs-232 to connect PLC's to devices like HM eyes input and output modules and motor drives just to name a few keep in mind that rs-232 is simply a form of serial communications or a way to transmit data a standard db9 cable is probably the most used cable for this application I hope this has been helpful in understanding just what rs-232 is used for check back soon for more real parts videos make sure that you head over to real parse comm to find even more training material for all of your plc programming needs [Music]

Channel: RealPars

Views: 609,984

Keywords: RS232, What is RS232, serial data transmission, DB9 cable, DTE, Data Terminal Equipment, DCE, example of DCE, serial communication standard, binary 0, binary 1, Data Communications Equipment, null-modem, RS232 protocol, Wire resistance

Id: eo9dbnrpspM

Length: 5min 41sec (341 seconds)

Published: Mon Sep 17 2018