CommFront CVT-485-1 User manual

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Industrial Port-Powered RS232 

RS485 Converter
(Part Number: CVT-485-1)
http://www.CommFront.com

Revision: 3.0 www.CommFront.com Page 2 of 4
■ INTRODUCTION
The CVT-485-1 is a compact, rugged, industrial-grade, port-powered RS-232 to RS-485
con erter, which can be used to con ert any standard RS-232C port into a two-wire
RS-485 port and ice ersa. The unit is efficiently powered from the RS-232 data line; it
also supports data direction auto-turnaround. Therefore, no external power, software
dri ers or flow control is required.
■ FEATURES
•Port-powered, no external power is required.
•Supports 128 nodes of RS-485 de ices.
•Operates reliably from 300 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 dri ers or flow control is required.
•Operating temperature: -40ºF to 185ºF (-40ºC to 85ºC).
•Built-in 600W surge protection, 15kV static protection and circuit protection.
•ALL-IN-ONE rugged terminal block with optional 120Ω terminator and 5VDC input.
•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-232C standard and RS-485 standard
Power Source: Port power from RS-232 data line
Current Consumption: Less than 10mA
Baud Rates: 300 to 115,200bps (auto-sensing and self-adjusting)
Distance: RS-232 side: 16ft (5m); RS-485 side: Depending on power from
RS-232 port, will transmit up to 4000ft (1.2km) at 19,200bps
Connector: RS-232 side: DB-9 Female; RS-485 side: DB-9 Male;
Termination Board: DB-9 Female and a 4-Way Terminal Block
Maximum number of drops: 128
End-of-Line Terminator: 120Ω (built-in, selectable)
Surge Protection: 600W
Static Protection (ESD): Up to 15KV
Dimensions (H x W x D): 0.63 x 1.3 x 3.4 in (16 x 32 x 86 mm) (with termination board)
Weight: 1.27 oz (36 g) (with termination board)
Operating Temperature: -40ºF to 185ºF (-40ºC to 85ºC)
Operating Humidity: Up to 90% RH (no condensation)
■ PIN ASSIGNMENT
RS-232 Side (DB-9 Female Connector):
Pin: 1 4 6 7 8 2 3 5
Signal: DCD DSR DTR CTS RTS TX RX GND
Function: tied together tied together TX RX GND
Note: Some software requires handshake
line acknowledgements. To satisfy the
requirements, the CVT-485-1's handshake
lines (RS232 side) are tied together
(DCD, DSR, and DTR tied together, CTS
and RTS tied together). Therefore, you
don't ha e to modify your existing
software.
Industrial Port-Powered RS232/RS485 Con erter
Part Number: CVT-485-1
Communications made easy

Revision: 3.0 www.CommFront.com Page 3 of 4
RS-485 Side (DB-9 Male Connector / Terminal Block):
DB-9 Pin: 1 3 5 9 6,7
Terminal Block: A+ B- GND +5V Jumper (120)
Function: RS485+ RS485- GND Optional +5V
DC input
Terminate/remo e Jumper 120 to
turn ON/OFF the 120Ω end-of-line
terminator
•The numbers on the left indicate the pin assignment of DB-9 male connector
(RS-485 side).
•The unit will function correctly only when the oltage on +5V pin is around
+5VDC (when RS232 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 o er 19.2kbps or the RS-485’s distance
exceeds 660ft (200m).
■ CONNECTIONS
■ 12 -OHM END-OF-LINE TERMINATION
Turn on the 120Ω end-of-line terminator on both ends of the RS-485 bus when the data rate is
o er 19.2kbps or the RS-485’s distance exceeds 660ft (200m).

Revision: 3.0 www.CommFront.com Page 4 of 4
■ INSTALLATION NOTES
•Connect PC’s (or other DTE de ice’s) COM port (or use a straight-through cable) to the
RS-232 side of CVT-485-1, use a crosso er (Null-Modem) cable for DCE de ice.
•120-Ohm terminator: If you are using the con erter with the pro ided terminal block,
terminate the Jumper “120” to turn ON the terminator and remo e it to turn the
terminator OFF. If you are using the con erter without the pro ided terminal block,
short pin 6 & 7 on the DB-9 connector (RS-485 side) to turn ON the terminator.
•The 120Ω end-of-line terminator adds hea y DC loading to a system; connect it only
when the data rate is o er 19.2kbps or the RS-485’s distance exceeds 660ft (200m).
•The unit comes with an optional 5VDC input; connect a regulated 5VDC power supply to
the +5V input if the port power is insufficient.
■ TROUBLESHOOTING
•Measure pin +5V and GND with a oltmeter, and be sure that it is around +5VDC
(when RS232 port is connected). Some COM ports, such as USB-RS232 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 232Analyzer software: Connect two
numbers of CVT-485-1 to your PC’s COM ports and run two instances of the
232Analyzer software, then send commands from one COM port, you should recei e an
echo of the commands sent on the other COM port. By performing a simple loopback
test like this, you can test both the transmitter and recei er of the con erter. This is
ery helpful when you are in doubt about the performance of your con erter.