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OPTO-ISOLATED RS232 TO RS485 CONVERTER
INDUSTRIAL PORT-POWERED OPTO-ISOLATED RS232 RS485 CONVERTER
The CVT-485-3 is a compact, rugged, industrial-grade, optically-isolated, port-powered RS232 to RS485 converter, which can be used to convert any standard RS232C port into a 2-wire half-duplex RS485 port and vice versa. This industrial opto-isolated RS232 to RS485 converter supports multi-drop RS485 networks and can be used to communicate with one loop of up to 64 units of RS485 devices. It operates within temperature range of -40ºF to 185ºF (-40ºC to 85ºC), features 600W surge protection, 15kV static protection and 2500V opto-isolation circuitry, which effectively protect your RS-232 devices from ground loops, noise problems, transient surges, remote lightning, and spikes. The device is efficiently powered from the RS232 data line, and it supports data direction auto-turnaround, which automatically enables the RS485 transceiver when data is present on the RS232 side. Therefore, it requires no external power, software drivers or flow control. The ALL-IN-ONE rugged terminal block, which was professionally designed for different requirements such as selectable 120-Ohm terminator and optional 5V DC input, makes the unit an ideal solution for all types of installations.
CommFront's product quality is ensured by our strict ISO 9001:2008 quality control system, and we back our high-quality RS232 to RS485 converters with a 30-day risk-free money-back guarantee and a 5-year replacement warranty.
PRODUCT PHOTOS (opto-isolated rs232 to rs485 converter)
FEATURES (ISOLATED RS232 TO RS485 CONVERTER)
- Converts RS232 to 2-wire RS485 and vice versa.
- Port-powered, no external power or RTS, DTR required.
- Industrial grade enclosed in a rugged, rustless ABS housing.
- 2500V optical isolation effectively protects your RS-232 devices from ground loops, transient surges, remote lightning and spikes.
- Supports multi-drop RS485 networks (up to 64 nodes).
- 1.2K to 57.6K Baud operation (auto-sensing & self-adjusting).
- Operating temperature: -40ºF to 185ºF (-40ºC to 85ºC).
- Accepts external 5V DC regulated power if the port-power is insufficient.
- Plug and play (hot-pluggable, data format auto-sensing & self-adjusting).
- Data direction auto-turnaround, no software drivers or flow control is required.
- Built-in selectable 120Ω terminator for system reliability and easy installation.
- Built-in 600W surge protection, 15kV static protection and circuit protection.
- ALL-IN-ONE rugged terminal block designed for different requirements.
- Surface Mount Technology manufactured to RoHS and ISO-9001 standards.
- Safety: Strictly certified by TUV (Cert No. SG-CE-090012).
- 5-year manufacturer's warranty.
SPECIFICATIONS (ISOLATED RS232 TO RS485 CONVERTER)
| Part Number: | CVT-485-3 |
| Compatibility: | EIA/TIA RS-232C standard and RS-485 standard |
| Power Source: | Port power from RS232 data line |
| Current Consumption: | Less than 10mA |
| Optical Isolation: | 2500Vrms (AC, 1 min) |
| Baud Rates: | 1,200 to 57,600bps (auto-sensing & self-adjusting) |
| Distance: | RS-232 side: 16 ft (5m); RS-485 side: Depending on power from RS232 port, will transmit up to 4000 ft (1.2km) at 19,200bps |
| Connector: | RS232 Side: DB-9 Female; RS485 Side: DB-9 Male; Termination Board: DB-9 Female and a 4-Way Terminal Block |
| Maximum number of drops: | 64 |
| End of Line Terminator: | 120Ω (built-in, selectable) |
| Surge protection: | 600W |
| Static protection (ESD): | Up to 15KV |
| Dimensions (H x W x D): | 0.6 x 1.3 x 3.5 in (16 x 32 x 88 mm) |
| Weight: | 1.36 oz (39 g) |
| Operating Temperature: | -40ºF to 185ºF (-40ºC to 85ºC) |
| Operating Humidity: | Up to 90% RH (no condensation) |
CONNECTOR PIN OUTS
RS232 Side
| DB-9 Pin | 1 | 4 | 6 | 7 | 8 | 2 | 3 | 5 |
| Signal | DCD | DSR | DTR | CTS | RTS | TX | RX | GND |
| Function | Tied | Tied | TX | RX | GND | |||
Note: Some software requires handshake line acknowledgements. To satisfy the requirements, our converter's handshake lines are tied together (DCD, DTR, and DSR tied together, and RTS and CTS tied together). Therefore, you don't have to modify your existing software.
 |
| DB-9 Female (view from front) |
RS485 Side
| DB-9 Pin | 1 | 3 | 5 | 9 | 6 | 7 |
| Terminal Block | A+ | B- | GND | +5V |
Jumper (120) |
|
| Function | RS485+ | RS485- | GND | +5V | Terminate/remove Jumper 120 to turn ON/OFF the 120Ω end-of-line terminator. | |
Note: The CVT-485-3 comes with a 4-way terminal block for easy wire connections. However, you may choose not to use the terminal block provided and simply follow the above table for pin assignments.
 |
| DB-9 Male / Terminal Block (view from front) |
120 OHM END-OF-LINE JUMPER SETTINGS
Important: Turn ON Jumper 120 (120 Ohm End-Of-Line Terminator) at both ends of the RS-485 bus when the data rate is over 19.2kbps or the distance exceeds 660 feet (200m).
CONNECTIONS (RS485 BUS)
Figure 1: Master-Slave Multi-Drop Connections (RS485)
1) Port power measurement
Measure pin +5V and GND with a voltmeter, and be sure that it is around +5VDC (when RS232 port is connected).
2) Loopback Test
- Connect two numbers of CVT-485-3 to your PC’s COM ports and connect A+ to A+, B- to B- on the RS485 terminal blocks (as shown above).
- Run two instances of the 232Analyzer FREE version software on your computer.
- Select "ASCII" for both the Send and Receive data formats. Then send command and/or string such as "CommFront" from one COM port. You should receive an echo of the command/string sent ("CommFront") on the other COM port. By performing a simple loopback test like this, you can test both the transmitter and receiver of the converter. This is very helpful when you are in doubt about the performance of your converter.
Screenshot 1: Send commands from 1st instance of the
232Analyzer software
Screenshot 2: Receive commands
from 2nd instance of the 232Analyzer software
232Analyzer is an advanced RS232 Serial Protocol Analyzer software that allows you to control, monitor and analyze serial port (RS232 / RS485 / RS422 / TTL, etc.) activities. Not just the data, it also allows you to monitor or change RS-232's line states: RTS, CTS, DTR, DSR, DCD, and RI.
The FREE version (no time limitation) can be downloaded from here.
TECH NOTES
RS-232: 3 easy steps to understand and control your RS232 devices
RS-485/RS422: Building a reliable RS485/RS422 network
