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Cooper Bussmann BU-245U-E Wireless Ethernet & Device Server User Manual
3.20 Digital Input/Output
The functionality of the shared Digital Input/Output pin may be configured via the “I/O Transfer”webpage. As this pin is shared, the Digital Input
status will be ON when the Digital Output is set ON.
The Digital I/O channel can be transferred to/from another device using Modbus (see section “3.15 Modbus I/O Transfer”) or it can be configured
to provide status of the module communications. If the BU-245U-E disassociates from another unit (that is,there is no wireless link), you can
configure the digital output to turn ON (set) or OFF (drop).
3.21 Modbus I/O Transfer
The BU-245U-E provides Modbus TCP Client and Modbus TCP Server functionality for I/O transfer.5000 x 16bit general purpose registers are
provided for Modbus (including the onboard Digital Input/Output) and are shared for both Client and Server.Modbus TCP Client (Master) and
Modbus TCP Server (Slave) are both supported simultaneously,and when combined with the built in Modbus TCP to RTU Gateway the BU-245U-E
can transfer I/O to/from almost any combination of Modbus TCP or RTU devices.
The layout of the BU-245U-E I/O Registers is summarized in the table below.Each register is internally saved as a 16 bit unsigned integer value. A
Modbus transaction may access the entire 16 bit value of any register,or alternatively the most significant bit of a register may be accessed as a
discrete value.The main use for the general purpose I/O registers is for intermediate storage, i.e., when transferring I/O from one Modbus Slave
device to another.Also provided is the status of the onboard digital I/O, as well as the status of the wireless link. The 16 bit status register
contains the value FFFF (hex) for ON and 0000(hex) for OFF.Inverted status registers are also provided where the registers contain 0000(hex) for
ON and FFFF (hex) for OFF.
Registers Purpose
1 – 4299 General purpose I/O registers (read/write)
4300 On-board Digital Input value (read only)
4301 Link Status (read only)
4320 On-board Digital Output value (read/write)
4370 On-board Digital Input inverted value (read only)
4371 Link Status inverted (read only)
4372-4999 Reserved for future use
Modbus TCP Client (Master) enables the BU-245U-E to connect to one or more Modbus TCP Servers (Slaves).
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