A1000 and A2000 SERIES CONVERTER BOXES USERS MANUAL REVISED:5/1/95 DGH CORPORATION PO BOX 5638 MANCHESTER, NH 03108 TELEPHONE: 603-622-0452 FAX: 603-622-0487 WEB: www.dghcorp.com The information in this publication has been carefully checked and is believed to be accurate; however, no responsibility is assumed for possible inaccuracies or omissions. Applications information in this manual is intended as suggestions for possible use of the products and not as explicit performance in a specific application.
A1000 & A2000 USERS MANUAL 2 GENERAL DESCRIPTION The A1000 and A2000 series converter boxes convert RS-232 communications signal levels to the correct electrical signals required by RS-485. The RS-485 communications standard is recommended when many modules, or other addressable devices, must be connected to a host computer over long distances. The A1000 and A2000 converters allow communications bus lengths up to 4,000 meters and baud rates up to 115K baud using one twisted pair of wires.
A1000 & A2000 USERS MANUAL SPECIFICATIONS Max Common Mode Voltage: 1500Vrms, 1 minute duration. NRZ asynchronous data format; 1 start bit, 7 data bits, 1 parity bit and 1 stop bit. Baud Rates: 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200. Temperature Range: Operating and Storage: -25 to +70°C Ambient. Relative Humidity: 0 - 95% Noncondensing. A1000 Power Specifications Power Requirements: 115 or 230 Vac ±10%, 50-60 Hz. Power Consumption: 30W Full Load. Power Supply Output: +24Vdc @ 1A.
A1000 & A2000 USERS MANUAL 4 A1000/2000 RS-232 DB-9 CONNECTOR The A1000 and A2000 contain a female DB-9 connector normally used with modems or other Data Communications Equipment (DCE).This connector should be connected to a host computer, or controller, when converting RS-232 signals to RS-485. The Transmit, Receive and Ground signal lines are all that is required for proper RS-232-to-RS-485 operation.
A1000 & A2000 USERS MANUAL This connector is left open when the A1000 or A2000 is used as an RS232-to-RS-485 converter. A1000/2000 RS-485 OUT CONNECTOR The A1000 and A2000 converters contain a four-pin screw terminal plug labelled RS-485 OUT. This connector is the RS-485 output for the A1000 and A2000 when used as either a converter or repeater. Figure 1A Connections for A1000. Figure 1B Connections for A2000.
A1000 & A2000 USERS MANUAL 6 BAUD RATE The A1000 and A2000 series converters each contain a 10-position DIP switch located on the rear panel. The DIP switch is used to select the correct communications baud rate and must be set to the same value as the devices connected to the RS-485 OUT connector. Only one baud rate switch may be turned on at one time. LEDS The A1000 contains three status LEDs labelled FAULT, POWER and TRANSMIT located on the converter front panel.
A1000 & A2000 USERS MANUAL should be placed at each end of the RS-485 cable. Please refer to Figure 2 for a typical RS-485 system application. The A1000 and A2000 each contain the biasing and termination resistors necessary to interface any equipment on an RS-485 network. These resistors are switch-selectable making it easier to interface the A1000 and A2000 to other pieces of equipment that may or may not contain the biasing and/or termination resistors. Figure 2.
A1000 & A2000 USERS MANUAL 8 A2000 RS-485 TERMINATIONS Proper biasing and termination resistors in the A2000 may be enabled by using the internal jumpers contained in the A2000. Figure 3 shows the location of the jumpers on the A2000 printed circuit board. The jumpers are shown in the factory setting to enable a resistor, insert a jumper into the jack position adjacent to the resistor nomenclature written on the A2000 printed circuit board.
A1000 & A2000 USERS MANUAL Figue 4a,b and c show simple wiring diagrams for both the A1000 and A2000 used as RS-232/RS-85 converters and RS-485 repeaters. Figure 4a Wiring diagram for RS-232/RS-485 converter with host DB-9 connector. Figure 4a Wiring diagram for RS-232/RS-485 converter with host DB-25 connector.
A1000 & A2000 USERS MANUAL 1 0 Figure 4c Wiring diagram for RS-232/RS-485 converter and RS-485 repeater .
