Rs422, specifications and in depth tutorial lammert bies. Example of rs485 communication cable beyond the network cabling, it is mandatory that the layout of printedcircuit boards and the connector pin assignments of rs485 equipment maintain the electrical characteristics of the network by keeping both signal lines close and equidistant to another. Specifications connectors, 2 rj45 modular 8conductor jacks 1 34 long, 1 diameter. I learned that there is a usb class for serial communication so i will not have to write device drivers for it. The integrated electronics also include an rs422 transceiver plus tx and rx leds which give a visual indication of uart traffic. Officially the rs485 specification allows only 32 nodes devices on the circuit. Rs422, also known as tiaeia422, is a technical standard originated by the electronic industries alliance that specifies electrical characteristics of a digital signaling circuit. This section summarises the key features of the ft232rq which apply to the usbrs422 usb to serial rs422 converter cables. Each usbrs422pcb contains a small internal electronic circuit board, utilizing the ft232r plus a usb typea connector. The usb 485c a db9 male connector on the rs485rs422 port, and a usb type a female on the usb port.
Usbrs422 ftdi, future technology devices international ltd. The rs422 usb converter transforms digital signals from a laseroptical sensor into a usb data packet. The integrated electronics also include the rs422 transceiver plus tx and rx leds that give a visual indication of traffic on the cable. The converter loops through further signals and features such as laser onoff, switch signals and function output. Rs422 allows a multidrop network topology, rather than a multipoint network where all nodes are considered equal and every node has send and receive capabilities over the same line. This means that you can use our converters and remote io. One problem is that you need to purchase an rs422 port or at least an rs422 to rs232 converter, since pcs dont come standard with this interface. The usbrs422 cable is a usb to rs422 levels serial uart converter cable incorporating ftdis. Rs422 systems can transmit data at rates as high as 10.
A nice feature of this converter is that each individual port can be set to either rs485 or rs422. Rs485rs422 autodetection, no jumper setting is required. I learned that there is a usb class for serial communication so i. Each ftdi usbrs422 cable contains a small internal electronic circuit board utilizing the ft232r that is encapsulated into the usb connector end of the cable. This manual may make reference to trademarks, registered trademarks, and other protected.
Rs422 devices can be used on an rs485 bus network if they are only used as recipients. The converter as well as the connected sensor are parametrisable by software. Low power rs485rs422 transceiver stmicroelectronics. Additionally, this converter comes with 15kv esd protection, surge protection and short circuit protection to. The rs422usb converts digital signals from up to 4 optical sensors into a usb data packet.
The rs422 usb converts digital signals from up to 4 optical sensors into a usb data packet. This section summarises the key features of the ft232rq which apply to the usb rs422 usb to serial rs422 converter cables. Shortcircuit protection the previous circuits ensured that the line was in a predictable state when idle or open. The adapter has a mini usb port and a surfacemount 8p8c rj45 jack. It was intended to replace the older rs232c standard with a standard that offered much higher speed, better immunity from noise, and longer cable lengths. The rs485 port supports autotranceiverturnaround, to support applications that control the. Ft232bl ft232bl usb uart circuit application note 93c66 sop ttl rs232 level converter lqfp32 maxim rs422 electronic power generator using transistor mi0805k400r00 altera date code formats text. Each usbrs422 cable contains a small internal electronic circuit board, utilising the ft232r, which is encapsulated into the usb connector end of the cable. The cable provides fast, simple way to connect devices with rs422 interface to usb. The usb 485c is a bidirectional usb powered usb to rs485rs422 converter with builtin 120 ohm termination option, which makes a halfduplex rs485 or a fullduplex rs422 available to a pc via the usb port. But because usb and ethernet require powerful interfaces with complex protocols, many efficient devices utilized rs232, rs485, and rs422 which is what this note is all about. The driver or generator is labeled d, the receiver is labeled r, and the termination impedance is zt. Usb to rs422 serial converter cable datasheet version 1. Rs485, rs422 and rs232 differences between the protocols.
This section summarises the key features of the ft232rq which apply to the usb rs422pcb. Rrss 442222 aanndd rrss 448855 aapppplliiccaattiioonnss eebbooookk a practical guide to using rs422 and rs485 serial interfaces v. Pdf rs422 gw232, gw232 rs232 gw232m gw232f rs422 to rs232 convertor circuit greenwich. Each usb rs422 pcb contains a small internal electronic circuit board, utilizing the ft232r plus a usb typea connector. With dip switches the user can select between 2wire rs485 or 4wire rs422. Rs422 is similar to rs232 protocol, and can be programmed in the same way, however, offers a few advantages and disadvantages. February 2009 rev 16 119 19 st485b st485c low power rs485rs422 transceiver features low quiescent current. I have a power meter that need rs485 to read data and i would like to make a rs232 to rs485 converter. Rs232, rs422, 4wire and 2wire rs485 15 kv esd protection level 4 against noise emissions and electrical voltage surges din rail and wall mountable rugged ip30 rated metal hub housing and screwlocking host connection, ideal for. It is an intelligent expansion module that connects to a pc or server via the universal serial bus usb, providing highspeed serial connectivity. This means that you can use our converters and remote io devices in more expansive situations. Instead of a single pair of biasing resistors for the entire line, the circuit has four biasing resistors at each node.
This interface circuit may operate without the signal ground connection, but may not be reliable. Usbrs422 ftdi, future technology devices international. The usb rs422 we 1800 bt from ftdi is an usb to uart cable with rs422 level uart signals. Max481max483max485 max487max491max1487 lowpower, slew. However, ic manufacturers have developed rs485 drivers capable of allowing 128 to 255 nodes on an rs485 lan. Each usb rs422 cable contains a small internal electronic circuit board, utilising the ft232r, which is encapsulated into the usb connector end of the cable. Two leds rx and tx are located on the left of the usb port, and a white power led is located on the left of the rj45 jack. At the desktop having rs232 port, so i built the rs422tors232 converter. Consult the dealer or an experienced radiotv technician for help. The rs485 port supports autotranceiverturnaround, to support applications that control the transmitter. Other aspects of rs422 such as cable selection and data rates will be discussed in the rs485 section of this application note. Communicate with one loop of up to 128 units of rs485rs422 devices. This manual may make reference to trademarks, registered trademarks, and other protected names andor symbols of thirdparty companies not related in any way. If you need to build a multipoint communication network rather than multidrop, rs485 is the right choice with a maximum of 32 parallel send and 32 receive units.
The new converter has 4 trigger inputs and a trigger output for connecting additional converters. The sensor and the converter are connected via the rs422 interface of the converter. The usb485c is a bidirectional usb powered usb to rs485rs422 converter with builtin 120 ohm termination option, which makes a halfduplex rs485 or a fullduplex rs422 available to a pc via the usb port. The rep4854229e is an effective solution for protecting rs485 and rs422 devices from voltage surges, lightning strikes, ground loop conditions and signal noise problems. This section summarises the key features of the ft232rq which apply to the usbrs422pcb. Throughout this document the generic terms of rs422 and rs485 are used when referring to equipment and. This connector provides the interface for connection to a usb host or hub port. Also, you may find that there are fewer devices supporting rs422. Driver is short circuit current limited and is protected against excessive power dissipation by thermal shutdown circuitry that placed the driver outputs into a highimpedance state. The usb485c a db9 male connector on the rs485rs422 port, and a usb type a female on the usb port. Usbrs232 converter usbrs422485 converter users manual. Example of rs485 communication cable beyond the network cabling, it is mandatory that the layout of printed circuit boards and the connector pin assignments of rs485 equipment maintain the electrical characteristics of the network by keeping both signal lines close and equidistant to another. Here is an ftdi application note with complete schematic in orcad and pdf.
It incorporates ftdis ft232rq usb to serial uart interface ic which handles all the usb signalling and protocols. To rs485 converter rs232 rs232 to rs485 converter dealextreme cool rs232 to rs485 converter circuit diagram. Thank you for purchasing the icusb422is usb to rs422485 converter with isolation. Rs422 was introduced to enable higher data rates to be transferred over serial data lines than was possible with rs232. Usb to rs422 uart serial converter pcb datasheet version 1. Data transmission circuit comprises mcu driverreceiver composed of max490 and peripheral components, and 422 usb converter. According to the design in section 3, a testing system is established in laboratory. The usbrs422pcb is a usb to rs422 level serial uart converter pcb incorporating ftdis ft232rq. Mar 21, 2015 the adapter has a mini usb port and a surfacemount 8p8c rj45 jack. Rs422 to rs232 convertor circuit datasheet, cross reference. Rs422 usb communication mode adopted in the electronic system improves communication rate and its antijamming ability.
Rs485 transceivers with integrated capacitive isolation to provide 2. Each ftdi usb rs422 cable contains a small internal electronic circuit board utilizing the ft232r that is encapsulated into the usb connector end of the cable. Icusb2324852 usb to serial adapter 2 port rs232 rs422 rs485 com port retention ftdi usb to serial adapter usb serial. Protocol comparison chart rs232 rs422 rs485 cable single ended. Smith serial communication products is your rs485 rs232 and rs422 authority for converters, repeaters, microprocessors, fiber optics, ethernet serial port server, ethernet serial products, mei, nodes and networks, usb, serial and digital io solutions, serial and analog io solutions including rs485, rs232, rs422, rs485, rs232, rs422, telemetry, process control, translators, extenders. With data format auto detecting and baud rate auto switching function, sc11u is able to automatically detect the data flow a nd switch the direction of the. It supports usb data transfer rates up to 12mbs, auto detects rs422 or rs485 compatible signals, and features zero jumper configuration for easy installation. The dcb converter requires plus dc voltage on rs232 pin one, or requires the external adapter to power the circuit. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause. If you need a usb to rs485 rs422 converter for older operating systems and legacy devices then this converters is suitable. The following table shows some of these notations and its equivalences. Rs485 has many advantages over both rs232 and usb when it comes to applications in noisy industrial environments. The st485 is designed for bidirectional data communications on multipoint bus transmission line halfduplex applications.
Short circuit protection the previous circuits ensured that the line was in a predictable state when idle or open. The circuit for ttltors422 converter is very simple. Eia standard rs422 data transmission the eia standard rs422a entitled electrical characteristics of balanced voltage digital interface circuits defines the characteristics of rs422 interface circuits. The aten uc485 usb to rs422485 adapter is a high quality. The rs422usb converter transforms digital signals from a laseroptical sensor into a usb data packet. Figure 4 is a typical rs422 fourwire interface between data terminal equipment dte and data circuit terminating equipment dce. The most common serial communication protocols are rs232, rs485, rs422, usb, and ethernet. Since both rs422 and rs485 are data transmission systems that use balanced differential signals, it is appropriate to discuss both systems in the same publication. Usb to rs232 rs485 rs422 optically isolated converter isolated rs232 rs485 rs422 to usb converter, model sc11u sc11u allows you to connect your serial devices to a usb interface. Rs422 is able to provide data rates of up to 10 mbps at distances up to 50 feet 15. Converts a single usb port into four rs232 rs422 rs485 serial ports over usb 2.
The circuit in figure 2 also protects the network as much as possible if the signal lines are shorted. The cable was 4wire phone cable having both end with rj11. The unit will convert rs232 to rs422, rs530, and v. Rs422485 to usb serial adapter cnet content solutions.
However using reduced data rates, rs422 is able to transmit data over distances of 4000 feet 1220 metres. Additionally, this converter comes with 15kv esd protection, surge protection and short circuit protection to protect both connected device and the converter itself. Interface compatibility the question of interface compatibility often comes up in nmea 0183 installations. A nice feature of this converter is that each individual port can be set to either rs485 or rs422 which means that you can use rs485 and rs422 simultaneously. To illustrate their basic differences, a condensed description of each standard is presented in the following subsections. Usb to rs485422 converter rs232, rs485, rs422, usb and. Rs422 to rs232 converter industrial version features converts rs422 to rs232 bidirectional 9pin dte pinout for rs232 compact size. For more information, please refer to the following manuals. Connect the equipment into an outlet on a circuit different from that to which the receiver is connected. Rs232 rs485 rs422 ttl usb serial fiber optic converters. The usbcom422plus4 is a usb to a quad interface rs422 level serial uart adaptor incorporating. Units test conditions maximum data rate 25 mbps rl 54. This unit is an intelligent expansion module that connects to a pc or server via the universal serial bus usb, providing highspeed serial connectivity. The technical aspects of these topics are the same for rs422 and rs485.
You can also find usb rs232 and usb rs422 interface examples in these datasheets. Il422 isolated rs422rs485 interface product datasheet. Usbrs422485 conversion adapter installation guide proface. Ultrabaud usb rs422rs485 serial converter 300 to 2000k baud.
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