Serial Port Connections
To communicate with the 485SDA10 module, it must be connected to an RS-422/RS-485 serial port. The 485SDA10 works with 2-wire or 4-wire RS-485. The unit automatically detects baud rates from 1200 to 9600. A data format of 8 data bits, 1 stop bit and no parity is used. Connections are made using terminal blocks. Table 2.2 shows the terminal blocks and their functions.
Table 2.2 - RS-485 Terminal Block Connections
TB | | 485SDA1 | |
Label | Signal | 0 Function | Notes |
| | | |
TD(A) | Transmit Data (A) | Output | Connection is required. [Loop |
| | | to RD(A) for 2-wire hookup] |
TD(B) | Transmit Data (B) | Output | Connection is required. [Loop |
| | | to RD(B) for 2-wire hookup] |
RD(A) | Receive Data (A) | Input | Connection is required. [Loop |
| | | to RD(A) for 2-wire hookup] |
RD(B) | Receive Data (B) | Input | Connection is required. [Loop |
| | | to RD(B) for 2-wire hookup] |
GND | Ground | - | Connection for Signal GND |
| | | and Power Supply GND. |
+12V | +12 V DC Power | Input | Connection is required. |
A typical 2-wire RS-485 connection is shown in Figure 2.3 and a typical RS-422 (or RS-485) 4-wire is shown in Figure 2.4.
NOTE: The 485SDA10 labels the data lines with “A” and “B” designators (per EIA RS-485 Specification). However, some RS-
485 equipment used “+” and “-“ as designators. In most cases the “A” line is the equivalent of the “-“ line and the “B” line is the equivalent of the “+” line. With an RS-485/422 system there are other factors that require consideration, such as termination and turn-around delay. For more information refer to the RS-485/422 Application Note (included in packing).
B&B Electronics -- 707 Dayton Rd. -- PO Box 1040 -- Ottawa, IL 61350
PH (815) 433-5100 -- FAX (815) 434-7094