CommFront CVT-485-1 User manual

Revision: 3.2
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Industrial Port-Powered RS232 

RS422/RS485 Converter
(Part Number: CVT-485_422-1)
http://www.CommFront.com
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■ INTRODUCTION
The CVT-485_422-1 is a compact, rugged, industrial-grade, port-powered RS-2 2
to RS-485 / RS-2 2 to RS-422 converter, which can be used to convert any
standard RS-2 2C port into a two-wire half-duplex RS-485 port, or a four-wire
full-duplex RS-485/RS-422 port and vice versa. It supports multi-drop
RS-485/RS-422 networks and can be used to communicate with one loop of up to
128 units of RS-485/RS-422 devices. The unit is efficiently powered from the
RS-2 2 data line and it supports data direction auto-turnaround. Therefore, no
external power, software drivers or flow control is required.
■ FEATURES
•Port-powered, no external power is required.
•Supports 128 nodes of RS-422/RS-485 devices.
•Operates reliably from 00 to 115,200 baud.
•Industrial grade enclosed in a rugged, rustless ABS housing.
•Plug and play (hot-pluggable, data format auto-sensing and self-adjusting).
•Data direction auto-turnaround, no software drivers or flow control is required.
•Operating temperature: -40ºF to 185ºF (-40ºC to 85ºC).
•Built-in 600W surge protection, 15kV static protection and circuit protection.
•Built-in selectable 120Ω terminator for system reliability and easy installation.
•Accepts external 5VDC regulated power if the port power is insufficient.
•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
Compatibility: EIA/TIA RS-2 2C standard and RS-485/RS-422 standard
Power Source: Port power from RS-2 2 data line
Current Consumption: Less than 10mA
Baud Rates: 00 to 115,200bps (auto-sensing and self-adjusting)
Distance: RS-2 2 side: 16ft (5m); RS-485/RS-422 side: Depending
on power from RS-2 2 port, will transmit up to 4000ft
(1.2km) at 19,200bps
Connector: RS-2 2 side: DB-9 Female; RS-485/RS-422 side: DB-9 M
ale; Termination Board: DB-9 Female and a 6-Way
Terminal Block
Max. number of drops: 128
End-of-Line Terminator: 120Ω (built-in, selectable)
Surge Protection: 600W
Static Protection (ESD): Up to 15KV
Dimensions (HxWxD): 0.6 x1. x .5 in (16x 2x90 mm) (with termination board)
Weight: 1.4 oz (40 g) (with termination board)
Operating Temperature: -40ºF to 185ºF (-40ºC to 85ºC)
Operating Humidity: Up to 90% RH (no condensation)
■ PIN ASSIGNMENT
RS-2 2 Side (DB-9 Female Connector):
Pin: 1 4 6 7 8 2 5
Signal: DCD DSR DTR CTS RTS TX RX GND
Function: tied together tied together TX RX GND
Note: Handshake lines are tied together to satisfy acknowledgement requirements.
Industrial Port-Powered RS2 2/RS485/RS422 Converter
Part Number: CVT-485_422- Communications made easy
Revision: 3.2

Revision: 3.2
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RS-485/RS-422 Side (DB-9 Male Connector / Termination Board):
DB-9 Pin: 1 2 4 5 6 7 8 4
Jumper: J2
(default: ON)
J
(default: ON)
J1
(default: ON)
J4
(default: OFF)
RS-485: A+ (J2 ON) B- (J ON) GND (J1 ON)
(J2 OFF) (J OFF) RS-422:
TX+ RX+ TX- RX-
GND (J1 OFF)
Terminate/remove Jumper J4
to turn ON/OFF the 120Ω
end-of-line terminator
ALL-IN-ONE Rugged Terminal Block:
•The numbers on the left indicate the pin assignment of DB-9 male
connector (RS-485/RS-422 side).
•The unit will function correctly only when the voltage on +5V pin is
around +5VDC (when RS2 2 port is connected). Otherwise, please
check the connection. External 5VDC regulated power supply is
accepted.
•The unit comes with a built-in selectable 120Ω end-of-line terminator;
connect it when the data rate is over 19.2kbps or the RS485/RS422’s
distance exceeds 660ft (200m).
■ CONNECTIONS
Revision: 3.2
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■ RS-485 / RS-422 MODE SETTING
■ 20-OHM END-OF-LINE TERMINATION
Turn on the 120Ω end-of-line terminator on both ends of the RS-485/RS-422
bus when the data rate is over 19.2kbps or the RS-485/RS-422’s distance
exceeds 660ft (200m).
■ TROUBLESHOOTING
•Measure pin +5V and GND with a voltmeter, and be sure that it is around
+5VDC (when RS2 2 port is connected). Some COM ports, such as USB-RS2 2
ports, come with an insufficient port power that is less than +/-5VDC; connect
a regulated 5VDC power supply to the +5V input in such a case.
•Perform a loopback test by using CommFront’s 2 2Analyzer software: Remove
Jumper 1 and terminate Jumper 2 and (or remove Jumper 1, 2, and then
connect TX+ to RX+ and TX- to RX-), then send commands from the
2 2Analyzer software. You should receive an echo of the commands sent. 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.