RS232-RS485 DB9 Converter – RMC/9R
RMC/9R is a RS232-RS485 DB9 converter that converts from RS232 serial standard (with a DB9 connector) to RS485 (with a 3-pin Mini XLR connector).
This industrial adapter is self-powered via the RS232 D-sub connector. It can be used to enable communication between a PC or industrial equipment and an RS485 serial bus, connecting from a DB9 connector with screw terminals to a 3-pin Mini XLR connector.
It is completely protocol-transparent, so it can be used with any proprietary protocol that operates over RS232. Data direction is completely automatic.
The device is fully Plug & Play and requires no drivers or DIP switches. The RS232-RS485 DB9 converter operates in half-duplex mode and automatically detects baud rates up to 250 kbps, making it easy to install in any new or existing system.
Description
RMC/9R is a RTS RS232-RS485 DB9 converter that converts from RS232 serial standard (with a DB9 connector) to RS485 (with a 3-pin Mini XLR connector). This industrial adapter is self-powered via the D-sub connector. It can be used to enable communication between a PC or industrial equipment and an RS485 serial bus, connecting a DB9 connector with screw terminals to a 3-pin Mini XLR connector.
The device is fully Plug & Play and requires no drivers or DIP switches. The RS232 serial port operates in full-duplex mode, while the RS485 serial port operates in half-duplex mode, with data direction controlled by the RTS (Request To Send) software signal. The RS232-RS485 DB9 converter automatically detects baud rates up to 250 kbps, so it can be easily installed in any new or existing system.
Use cases
The very compact size of this converter allows it to be installed in tight spaces where there is physically no room for a traditional DIN-rail converter. Another scenario in which this RS232-RS485 DB9 converter may be necessary is when a machine has only a DB9 (or, more precisely, D-sub) port and can communicate only through that port. This converter can be secured to the machine on the D-sub side with screws for maximum communication reliability.
If it is necessary to isolate the communication to protect the computer from minor or moderate interference, an isolated converter such as ISC/9R is recommended; however, it must be powered externally with a DC power supply ranging from 5 V to 12 V DC. This converter can be powered by 5 V to 12 V DC via a standard jack and can be connected, for example, to a USB port or using a custom power cable.
In industrial environments, communication interference is common, and it is good practice to protect devices that communicate externally.
Protocol
The RMC/9R RS232-RS485 DB9 converter is completely protocol-independent. This means that the converter is transparent to the communication and can be used with any proprietary protocol.
This is possible because the converter operates at the logic level rather than at the protocol level. Therefore, this RS232-RS485 DB9 converter can be used with any computer or machine that communicates via a DB9 port using the RS232 serial standard.
Data direction is completely automatic.
Versatility
The RS232-RS485 DB9 converter is also available with automatic data direction or with different connectors. The RSC/9R converter, for example, is functionally identical to RMC/9R, but data direction is controlled by software (RTS, Request To Send). IMC/9R and ISC/9R feature an RS485 interface isolated up to 50 V, should this be required for added protection, with automatic data direction or RTS, respectively.
The DFP/9S and DFP/9A industrial serial converters have a synthetic optical fiber output with a screw-type connector to electrically isolate the equipment. All combinations of serial standards, optical fiber, and power supply are available in the catalog, while special requests (such as higher baud rates) can be made via the contact form.
Technical Specifications
Main features
| Power supply | Self-powered via DB9 |
|---|---|
| Power consumption | 1 W |
| Serial transmission data rate | 0 – 250 kbps (automatic) – higher data rates on request |
| RS232 connector | D-sub (DB9) |
RS232
| Communication type | Full duplex |
|---|---|
| RX input voltage | 1.5 V low input threshold – 1.8 V high input threshold (± 25 V max) |
| TX output voltage | ± 5 V (± 5.4 V max) |
| ESD performance RX / TX | ± 15 kV (Human Body Model) – ± 8 kV IEC61000-4-2 contact discharge |
RS485
| Communication type | Half Duplex on a balanced line, with automatic data direction |
|---|---|
| Maximum bus voltage | ± 60 V – ESD ± 16.5 kV (Human Body Model) |
| Common mode range | ± 25 V DC |
| Slew rate | Limited, to have an error-free transmission |
Mechanical features
| Dimensions | 48 mm x 31 mm x 25 mm |
|---|
Working conditions
| Degree of protection | IP20 |
|---|---|
| Operating temperature | -20 °C to +50 °C |
| Storage temperature | -40 °C to +80 °C |
