B&B Electronics Buffered Smart Switch, 232BSS4 guide

Slave Devices that Require Polling:

This configuration will also work with systems where the devices have to be polled for information. With the setup of Figure 2.3, the switches can be configured so that you still only have to send one set of switching characters. To do this, set the switches up in the following way:

•Set the switch on Level 1 to broadcast to all slaves on startup.

•Set the switch on Level 1 to Auto Select mode, no preamble.

•Set the switch on Level 1 for 0 Port Time

•Set the switch on Level 1 for a short Inactivity Time. Somewhere around 5 milliseconds or so.

•Set the switches on Level 2 for no Auto Select.

•Set the command sequences on the Level 2 switches to be unique from each other. One suggestion is to use a 3 character command. Use the first character as a start of command character like STX. The second character could represent the address of the Level 2 switch you are going to. The third character is the command character.

•Write the software to send the command to select the port. By setting the Layer 1 switch to broadcast and Auto Select, only 1 set of command characters is needed.

Cascading switches becomes more complicated when the devices are a mix of polled and automatic sending of data. It is also difficult to cascade when devices are streaming data constantly, or automatically sending a variable length packet of data.

20	Documentation Number 232BSS4-2907m

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B&B Electronics Buffered Smart Switch, 232BSS4 manual Slave Devices that Require Polling

Contents

Buffered Smart Switch Model 232BSS4This product designed and manufactured in Ottawa, Illinois USA of domestic and imported parts byPage Table of Contents CHAPTER 4 SETUP SOFTWAREAPPENDIX B CABLE CHARTS APPENDIX C BLOCK DIAGRAM Documentation Number 232BSS4-2907m Chapter 1 - Introduction Documentation Number 232BSS4-2907m Specifications Default Parameters Checklist 1. RS-232 Buffered Smart Switch model 232BSS4 2. Instruction ManualThe following equipment should be in the shipping carton 3. 2 3.5 floppy disks Documentation Number 232BSS4-2907m Symbols and Conventions LED IndicatorsChapter 2 OPERATION Port Configurations Smart Switch Only Mode DescriptionOptions Command Summary Three Character Command FormatFour Character Command Format Command Explanation Commands Select Port A to transmit and receive - “A” VB Example Table 2.2 Send Only and Clear Buffer Control Characters Table 2.3 - Timer Values commands and the Master can initiate the next communications sequence Auto Select/Smart Switch Mode Inactivity Time Using the 232BSS4 as a Buffered Splitter/Combiner Figure 2.1. Multiple Terminals to a Host Controller Back to Back Operation mux/demux Figure 2.2. Back to Back Operation Cascading Multiple Switches Figure 2.3. Expanding the Number of Slave Ports Slave Devices that Automatically Send their Data Slave Devices that Require Polling Chapter 3 PORT CONNECTIONS DTE/DCE Explanation25 Pin DTE 25 Pin DCE Master Port Connections Slave Port Connections Chapter 4 SETUP SOFTWARE IntroductionConnection Software Installation Software UninstallSelect SETTINGS, CONTROL PANEL from the Windows START menu Double Click ADD/REMOVE PROGRAMS Setup Tutorial Single Unit Main Screen 26Documentation Number 232BSS42907 Manual Back to Back Main Screen 28Documentation Number 232BSS42907 Manual Copying Parameters Between Switches Default Parameters Documentation Number 232BSS42907 Manual Appendix A ASCII Character Codes DECIMAL to HEX to ASCII CONVERSION TABLEASCII Appendix A Appendix B Cable Charts Pins 6, 8, & 20 looped back internally on the 232BSS4Chart B.1. DTE PC DB25 Connector to Master Port Chart B.2. DTE PC DB9 Connector to Master Port Appendix B Cable Charts Pins 6, 8, & 20 looped back internally on the 232BSS4 Chart B.3. DCE Modem DB25 Connector to Master PortChart B.4. DCE Modem DB9 Connector to Master Port Pins 1, 4, & 6 looped back internally on the 232BSS4 Chart B.5. Ports A - D DTE to DTE PC DB25 ConnectorChart B.6. Ports A - D DTE to DTE PC DB9 Connector Chart B.7. Ports A - D DTE to DCE Modem DB25 Connector Pins 1, 4, & 6 looped back internally on the 232BSS4 Chart B.8. Ports A - D DTE to DCE Modem DB9 Connector Appendix B Cable Charts Appendix C Block Diagram MASTERUART UART UART Appendix C Appendix D Declaration of Conformity DECLARATION OF CONFORMITY