Elpro Technologies 450U-E Wireless Ethernet Modem & Device Server User Manual
Rev Version 1.0.12-Beta7
www.cooperbussmann.com/wirelessresources
15
Failsafe Biasing
The 450U-E does not support Failsafe Biasing on the RS485 unless a 115S serial expansion module is also
connected and has its termination switch enabled.
Failsafe Biasing is a simple voltage divider that is connected to the RS485 bus and
pulls the terminal voltages (high or low) when the communication state is idle rather
than be left at a floating state which could cause data corruption.
If connecting a serial device that does not support Failsafe Biasing and an 115S
expansion I/O module is also not fitted then Biasing resistors must be wired to each
RS485 terminal to ensure correct operation. Resistor values will depend on the
Supply voltage; see diagram for resistor value calculation and wiring.
USB Ports
Module has a two USB ports housed under the plastic bung on the top plate.
USB A Host port is used for upgrading the module firmware and can only be used for full upgrades. Patches files
are not loaded via the USB but through the web interface. The procedures for performing a full firmware upgrade
and the patch file upgrade can be found in Section Appendix A - Firmware Upgrades
USB B Device connector which is used as a secondary Ethernet connection point. Essentially this is a USB to
Ethernet converter that will allow you to connect to the modules web interface without the need for disconnecting
the existing Ethernet connection or the need to install a hub or switch to allow more ports.
Input/Output Connections
2.4
The 450U-E has a single physical on-board I/O channel that can be configured as either a Digital or an Analog via the web
interface. The Digital channel can act as an input or an output. It can be monitored, set remotely, or alternatively used an
output for a communications alarm status. If more I/O is required, you can add 115S serial expansion I/O modules via the
RS232 or RS485 ports. See section 3.16 for more details on this.
Analog Input
The I/O channel can be configured to except a 0-20mA current sinking analog input.
Current source must be externally powered and the DIO must be configured for Analog Input rather than Digital
Input/Output. This can be configured by going to the
/
screens see
section 3.16 for details.
Figure 15 -Multidrop Serial
