B&B Electronics ESP904 - RS-232 Mode; RS-422 Mode; RS-485 Mode

Installing the VLINX ESP Software
Manual Documentation Number: ESP904-0504 Chapter 2 15
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104 – www.bb-elec.com
B&B Electronics Ltd – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445 – www.bb-europe.com
RS-232 Mode
In RS-232 Mode the serial port is configured to support eight RS-232 signal
lines plus Signal Ground and is configured as DTE like a computer. Signals
are single ended and referenced to Ground. To use handshaking, Flow
Control must be set to RTS/CTS during Configuration.
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Refer to Appendix A for RS-232 connection pin-outs.
RS-422 Mode
RS-422 Mode supports four RS-422 signal channels with full duplex
operation for
Receive, Transmit, RTS (Request To Send) and CTS (Clear To
Send). The data lines are differential pairs (A & B) in which the B lines
positive relative to the A lines. Ground provides a common mode reference.
To use handshaking Flow Control must be set to RTS/CTS during
configuration.
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Refer to Appendix B RS-422 connection pin-outs.
RS-485 Mode
RS-485 Mode supports the transmit (TX) and receive (RX) signal channels
using 2-wire, half-duplex operation. The data lines are differential with the
Data B line positive relative to Data A in the Mark state. Ground provides a
common mode reference.
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Refer to Appendix C for RS-485 connection pin-outs.
RS-485 Receiver Biasing can be implemented from the ESP904 if the
network does not supply it. Remove the two side-cover screws of the
ESP904, slide the cover off and re-position the bias jumpers (shown open in
the figure below) to enable biasing (shorting).
Installing the VLINX ESP Software
16 Chapter 2 Manual Documentation Number: ESP904-0504
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104 – www.bb-elec.com
B&B Electronics Ltd – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445 – www.bb-europe.com
Figure 10. Internal Setting to Select RS-485 Bias
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(For more information on RS-485 Receiver Biasing, see B&B Electronics RS-
422/485 Application Note available at www.bb-elec.com)