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Part: 485HSPR
Category:
Interface and Interconnect
-> Line Drivers
Description: Rs-232 to Rs-485 ISOlated Converter
Company: B&B Electronics
Datasheet: Download 485HSPR datasheet File size : 83 kB
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Datasheet text preview:
Document No. 485HSPR4300 - pg. 1/3
High Speed (115kb) RS-232 to RS-422/485 CE Optically Isolated Converter With Surge Suppression CE
Model 485HSPR The 485HSPR is a high speed RS-232 to RS-422/485 converter with optical isolation and surge protection. RS-485 is an enhanced version of the RS422 Standard that allows multiple drivers and receivers on a 2 or 4-wire system. The RS-232 port has a female DB-25 connector with pins 2 (TD), 3 (RD), and 7 (Signal Ground) supported. Pins 4 (RTS) and 20 (DTR) are used to power the RS-232 side of the converter. If your port cannot supply this power, a power supply may be connected to the RS-232 pins 25 (+12 VDC) and 12 (ground). The RS-485 DB-25 male connector provides connection for Transmit Data A(-) and B(+), Receive Data A(-) and B(+), and Signal Ground. There is a power jack on the side of the converter which can be used to power the RS-485 side. A power supply is available from B&B as Part # 485PS. Power may also be connected through the 485 connector on pins 25 (+12 VDC) and 12 (ground).
Figure 1 JUMPER SELECTION: DRIVER CONTROL Table 1 - Jumper Settings Jumpers JP1, JP3, and JP4 set the method used to control the JP1 JP2 JP3 JP4 RS-422/485 driver. Installing the jumper in position JP1 leaves the driver RS-422 4-Wire Mode constantly enabled. This position should be used for RS-422 operation X and when the 485HSPR will be the master node of a 4 wire RS-485 RS-485 2-Wire Mode system. RTS Control Jumper position JP3 allows the driver to be directly controlled from ? X the RS-232 RTS handshake line. The RS-232 device must raise RTS Send Data Control ? X when transmitting out to the RS-422/485 system. When you are through RS-485 4-Wire Mode transmitting, RTS must be lowered to allow the 485HSPR to receive and allow other drivers on the line to transmit. RTS Control X Installing jumper JP4 enables an automatic send data circuit in the Send Data Control 485HSPR that takes care of the control of the RS-422/485 driver. This X circuit senses data on Pin 2 (Transmit Data) of the RS-232 side of the X = Jumper in place converter and turns on the RS-422/485 driver. When the data is through ? = Remove JP2 to enable echo feature transmitting, the 485HSPR waits one millisecond before shutting of the RS-422/485 driver. This preset time-out allows continuous transmission of data at 9600 baud or higher. If you need to change to a baud rate lower than 9600 baud, or would like to configure the 485HSPR for a specific rate, the time-out can be changed by changing the values of R15 and C9 according to Table 2. If these components need to be changed, you can remove the surface mount components and install new values in appropriate holes provided on the bottom of the board. See Figure 1 for the location of R15 and C9. NOTE: Only 1 of these 3 jumpers can be in place at a time. Which one depends on your configuration.
© B&B Electronics -- Revised November 2000
This product designed and manufactured in USA of domestic and imported parts by
Document No. 485HSPR4300 - pg. 2/3 JUMPER SELECTION: RECEIVER CONTROL The jumper JP2 (echo) determines when the RS-422/485 receiver will be disabled. Removing this jumper leaves the receiver on at all times. JP2 should be removed for any four wire setup including RS-422 operation. Putting JP2 on disables the receiver whenever the driver is turned on. This is useful in two wire mode when you do not want to see an echo of the data sent from the RS-232 device. Up to 32 receivers can be driven by any one RS-485 driver, allowing you to put together large systems with many drop points. If you are using termination resistors, they should be located at opposite ends of the system. Figure 3 shows how to interconnect two RS-485 converters in a halfduplex system using two wires. The resistors Rt is optional, depending on line length, baud rate, etc. The resistor Rt should be about the impedance of the line used, which is normally about 120 ohms each. Proper operation of any RS-485 system requires the presence of a return path. The RS-485 Standard recommends that a third wire be used for this. For safety, a 100 ohm, 1/2 watt resistor should be connected between Signal Ground and the "reference wire" at every drop point. While it may be possible to interconnect Signal Grounds directly, this is not recommended due to the danger of circulating currents possibly being present. No wire type or maximum run length is listed in the RS-485 Standard. However, The RS-422 Standard (which is very similar) recommends number 24 AWG twisted-pair telephone cable with shunt capacitance of 16 picofarads per foot, and no more than 4000 feet long.
Table 2 COMPONENT REPLACEMENTS CHANGING BAUD RATE Baud Rate Time (ms) Resistor Capacitor (R15) (C9) (ohm) (mfd)
300 600 1200 2400 4800 9600 19200 38400 57600 115200
33.3 16.6 8.33 4.16 2.08 1.04 .520 .260 .176 .0868
330K 160K 820K 430K 200K 100K 56K 27K 16K 8.2K
0.1 0.1 0.01 0.01 0.01 0.01 0.01 0.01 .01 .01
SPECIFICATIONS: Data Rate: Connectors: RS-232 Side: RS-422/485: Isolation: Surge Suppression:
Up to 115.2K baud DB-25 Female (DCE) DB-25 Male (RS-530 Pinouts) 2500VAC Optical Isolation of Data Signals & Ground 7.5V, bi-directional avalanche breakdown device. 500W peak power dissipation. Clamping time < 1 picosecond (theoretical). 6,000 pF maximum capacitance. Port-powered or 12VDC @ 30ma 12VDC @ 100ma
Power Requirements: RS-232 Side: RS-422/485:
DECLARATION OF CONFORMITY
Manufacturer's Name: Manufacturer's Address: B&B Electronics Manufacturing Company P.O. Box 1040 707 Dayton Road Ottawa, IL 61350 USA 485HSPR Reversed Optically Isolated RS-232 to RS-422/485 Converter Light industrial ITE equipment 89/336/EEC EN 50082-1 (IEC 801-2, IEC 801-3, IEC 801-4) EN 50081-1 (EN 55022, IEC 1000-4-2) EN 61000 (-4-2, -4-3, -4-4, -4-5, -4-6, -4-8, -4-11) ENV 50204 EN 55024
Model Numbers: Description: Type: Application of Council Directive: Standards:
Michael J. Fahrion, Director of Engineering
© B&B Electronics -- Revised November 2000
This product designed and manufactured in USA of domestic and imported parts by
Document No. 485HSPR4300 - pg. 3/3
© B&B Electronics -- Revised November 2000
This product designed and manufactured in USA of domestic and imported parts by
Others parts begin by 48
48-1 48-2
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