Brian Dorey made this DIY USB to RS485 adapter, that is available at Github:
We looked for a full-duplex ready-made adapter but all the ones we found are only half duplex devices and as we needed to be able to supply 12 volts via the RJ45 connectors on the slave boards we decided to make our own USB to RS485 full duplex adapter using a USB converter chip from FTDI.
The board uses an FT230X with an RS485 converter chip which outputs to a set of header pins and also an RJ45 socket.
The new adapter board can supply power to the slave devices through the USB port or can be powered from an external supply by removing a power selector jumper. The board also has an on board 120R terminator resistor with selection jumper and LED’s to show serial activity.
USB to RS485 adapter - [Link]
A big advantage is, that practically the whole RadiCal series is also available with top-level EC motors, which are in principle motors with permanent magnets with very low power consumption (up to 50% savings).
High quality material of blades and impeller is highly resistant to ageing and corrosion ( for example also to a salt water) and it´s UV resistant. The RadiCal series contains wide range of sizes from 133 to 630 mm. At sizes over 250mm there are even available types with possibility of control via RS485 – MODBUS RTU. Majority of types is available in a basic version, intended for insertion into a suitable holder/ housing or also with an integrated holder – support basket.
What does the RadiCal series brings briefly?:
- high efficiency
- extremely quiet running with optimized air flow
- substantially decreased rotation noise
- unmatched compactness
- robust design and maintenance-free operation
- meets ErP specifications
In respect to a reliable, quiet and energy efficient operation, fans of the RadiCal series are suitable for a wide range of appliances like cooling of electronics, computers and servers, HVAC, heat recovery systems, etc.
In our standard stock offer can be found a few types of RadiCal series (for example R2E190 and R2E220) and upon order we´re able to deliver you any type from the EBM Papst portfolio. Detailed information will provide you the RadiCal centrifugal fans catalogue (49 MB).
Do you need a radical solution of ventilation or cooling? - [Link]
Ethan Zonca of Protofusion writes:
While developing the Luma RS485-networked LED driver we discovered a need for a small and inexpensive USB to RS485 adapter. We designed an adapter with a FTDI basic UART chip (FT230XS) and an inexpensive TI differential receiver (SN75176). Our small selection of parts brings the cost down to just over $5 for one adapter.
Open hardware USB to RS485 adapter - [Link]
Integrated circuit FT232R is becoming legendary and we bring you another example of FTDI USB chips usage.
In praxis we often face a requirement to communicate with devices, which have serial ports RS232, RS422 and RS485. As many devices – mainly notebooks, already usually don´t have these ports, it is necessary to use a converter to convert serial port to USB.
Company ComErgon, s.r.o. is long-term dedicated to development and production of such converters. ComErgon has in its offer models for RS232, RS422 a RS485 interfaces. USB to RS422 and RS485 converters are produced with a 1kV galvanic isolation, as lines on the RS422 and RS485 side can be lead even on long distances and an eventual overvoltage could be able to damage end devices. Version RS232-USB is available with galvanic isolation but also without isolation.
More detailed information and technical specification of these converters can be found at website of company ComErgon.
Company ComErgon focuses on development and production of converters for RS232, RS422, RS485, RS422/RS485 repeaters, serial to Ethernet interface modules, GPRS, Fiber Optic, 433MHz, current loop and other.
Customer solution: Trouble-free RS232, RS422, RS485 to USB conversion - [Link]
3in1 universal converter. Based on FTDI 232R chip seen as normal COM port, and two serial converters MAX232 and MAX485. Allow to be used as RS232, RS485, or UAR TTL converter. Connections parameters can be set through the system, as in normal COM port. Supported speeds: 110 to 921600bps.
3in1 converter – USB to RS232, RS485, UART - [Link]
This project is one of many I have undertaken to control my house using a set of rules, a web interface, a logger and many more components. This project is a light dimmer which has multiple control interfaces such an RS485 network, an infrared remote control, a proximity touch slider or touch sensor.
Network Light Dimmer – [Link]
Is the evolution of the binary clock and allows planning time ON and time OFF for a relay. To keep consumption low a bistable relay was used, ’cause it needs power only when the status changes. Through the two buttons you can set time ON, time OFF and the current time. To drive the single coil bistable relay I used an RS485 driver, because it can provide 60mA output.
Daily Timer with binary display - [Link]
Today, although the wireless technology grows very fast, the long distance funicular communication still keeps its popularity. The reason is obvious that cost and complexity is high at the wireless communication.
RS232 is probably one of the most used, easy to develop and easy to apply communication protocol. We generally encounter to this standard at the MCU applications. But it has some restrictions. It allows us to use maximum 15 meters cable. Good wiring, low baud rates and less noisy mediums may allow us to exceed this limit a little more. The main problem here , when the distance increases, the noise at the common ground line also increases. Another issue, RS232 allows only two devices to communicate reciprocally. More than two devices can not communicate at this line and we need another solution for this situation.
RS485 is the standard that solves this problems. The main difference is, RS485 transfers the data depending on the potential difference between the two communication wires. The polarity defines the logic state of the signal. You can transfer data up to 1220 meters far away and with a rate up to 10 Mbs.
RS232 – RS485 Converter with Automatic RX – TX Control – [Link]
This converter is intended to use with PC computer to communicate with ROV using 2 wires in half duplex mode. Send/receive mode is selected by RTS signal. The converter was designed to be as simple as possible, so it has no some features that can be found in commercial grade products.
RS485 to RS232 converter - [Link]