Ten port managed industrial ethernet switches (107 pages)
Summary of Contents for B&B Electronics 485DSS
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Distributed Smart Switch Model 485DSS Documentation Number 485DSS-0812 This product Designed and Manufactured In Ottawa, Illinois of domestic and imported parts by B&B Electronics Mfg. Co. Inc. 707 Dayton Road -- P.O. Box 1040 -- Ottawa, IL 61350 PH (815) 433-5100 -- FAX (815) 433-5105 Internet: http://www.bb-elec.com...
ISTRIBUTED MART WITCH OMMANDS The Command String ................. 10 ON Command ..................10 OFF Command .................. 11 STATUS REQUEST Command............11 485DSS A ............14 ETTING THE DDRESS Table 4. Address Switch ..............14 ................. 15 INARY RANSFER CHAPTER 2: SOFTWARE ..............16 ..................
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1. IBM PC DB25 C ........... C-1 HART ONNECTOR TO 485DSS RS-232 (DTE) P ............C-1 3. RS-232 DCE D /DB25 C ....C-1 HART EVICE W ONNECTOR TO 485DSS RS-232 (DTE) P ............C-1 2. IBM PC DB9 C ..........
The RS-485 Distributed Smart Switch (485DSS) connects one RS-232 device to an RS-485 multi-node network as shown in Figure 1. To accomplish this, the 485DSS converts RS-232 to an addressable RS-485 node. A unique address, from 0 to 255, is user assigned by setting switches on the 485DSS.
Figure 2. Top View of Circuit Board Port Configuration The 485DSS has a RS-485/422 port and a RS-232 port. The RS- 485/422 signals are on terminal blocks. Table 1 shows you the pinouts and Figure 2 shows you the location of the terminal blocks.
2. IBM PC's are DTE devices and modems are DCE devices. Only TD and RD of the RS-232 port pass through to the RS-485 port when the 485DSS is ON. The 485DSS raises and lowers the RTS output signal on the RS-232 port to reflect the connect state of the port.
Host, the microcontroller will automatically enable the driver before transmitting the first character of the reply and disable the driver after the last character of the reply. When the 485DSS is ON (selected) and the RS-232 device is transmitting data to the Host the Send Data (SD) control circuit enables and disables the driver.
Table 3 into the R21 position. Use Figure 2 to locate R15 and C10. NOTE: The SD timing circuit does not control the RS-485 driver when the 485DSS sends reply messages to the host. Table 3. Component Values For Send Data Timing...
Figure 3. RS-485 Wiring Diagram 4-Wire Mode To configure the 485DSS for RS-485 or 422 four-wire mode, place the jumper in the 4W position. Refer to Figure 4 for connecting information and Figure 2 for the jumper location. In this position on a 4-wire network the Host and the RS-232 device can communicate in full duplex.
B&B Electronics’ free RS-422/485 Application Note. Power Supply The 485DSS requires an unregulated DC power source that will supply +12 volts at 100 milliamps. Connect the positive side of the power source to the +12VDC terminal block and the common side of the power source to the GND terminal block.
The host computer of the RS-485 network controls each 485DSS on the network by sending them command messages. These commands can turn a 485DSS on or off, and can also request status from an individual or from all of the 485DSS's on the network.
HOST can reset its communication format to match the format of the RS-232 device attached to the 485DSS. ALL data is passed through the unit after it has been selected. The 485DSS does not have any buffering. Distributed Smart Switch Commands The 485DSS constantly monitors the serial data received on the RS-485/422 port for a command string.
"X-off" (decimal 19). The second and third characters represent the hexadecimal address of an individual 485DSS. The address range is from 0 to 255 (HEX "00" to "FF"). Some commands require the use of the broadcast character "DC2"...
RS-232 device is requesting access to the network and if it has access to the network. By using this command the Host has the ability to prioritize all the 485DSS's on the network. A specific address in the address field specifies a response from an 485DSS-0812 Manual B&B Electronics Mfg Co Inc –...
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485DSS that sent the message. The address range is from 0 to 255 (HEX "00" to "FF"). The fourth character indicates the select state of 485DSS, a "0" (decimal 48) indicates the RS-232 port does not have a connection (not selected) to the network and a "1"...
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Example: A unit with a decimal address of ten will have a delay of 220 milliseconds [(10 x 0.02) + 0.02 = 0.22 seconds]. Command character: ACK (decimal 6) Example 1: To request status from the 485DSS set to address 11 ( 0B hex) decimal. HOST transmits: Xoff “0”...
To access this switch, you will need to remove the top cover of the 485DSS. Insert a small screwdriver in the slot in the side of the cover and twist to remove it. Each switch position is equal to a specific weight value.
When transmitting binary files through the Distributed Smart Switch, it is possible that a string of characters could resemble a 485DSS command message. If this would happen, there could be a disruption in the transfer process and a loss of data. A simple solution to this problem is to change to a different baud rate before transferring binary files.
The Distributed Smart Switch Demonstration (DSS_DEMO) Program (IBM PC or Compatible) provides the user with examples of how to receive and transmit commands to the 485DSS. The DSS_DEMO.EXE is a DOS executable program written in QuickBasic that will send turn on, turn off, and status request commands to the 485DSS.
Appendix C: Cable Charts These charts indicate some common cable wiring based on the 485DSS RS-232 and RS-485/422 ports. Refer to the Port Configuration section of this manual for more information. Chart 1. IBM PC DB25 Connector to 485DSS RS-232 (DTE) Port...
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485DSS Serial Port Signal RS-232 (DTE) Port DB9 Connector Direction DB25 Connector -----------> <----------- <---------> <----------- -----------> Chart 5. RS-422/485 4-Wire Device to 485DSS RS-422/485 Port. RS-422/485 485DSS 4-Wire Signal RS-485/422 Device Direction Terminal Blocks TD (A)(-) -----------> RD (A) TD (B)(+) ----------->...