Communications hardware requirements, Rtu communication requirements, Tcp communication requirements – Basler Electric BE1-700 Modbus Protocol User Manual
Page 20: Detailed message query and response, Read holding registers, Query, Communications hardware requirements -10, Rtu communication requirements -10, Tcp communication requirements -10, Detailed message query and response -10

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BE1-700 Modbus™ Protocol
9376700991 Rev D
Figure 1-14. DOS Command Example of Default IP Address Detected
7) Once your PC has an IP address, the BE1-700 BESTCOMS™ PC software program or the Digi
Discovery program (
dgdiscvr.exe) can be used to determine the IP address of the BE1-700. A BE1-
700 with style number xxxxx7x (Modbus/TCP over Ethernet) must use the Modbus ping software
program (
ruiping.exe)
8) In the Basler Modbus/TCP Device Discovery program, click on Refresh to discover the IP address.
Communications Hardware Requirements
RTU Communication Requirements
The BE1-700 RS-485 physical interface is three positions of a terminal strip with locations for
Send/Receive A (A), Send/Receive B (B) and Signal Ground (C). Refer to the BE1-700 Instruction Manual
(9376700990) for further details.
TCP Communication Requirements
The BE1-700 Ethernet port (RJ-45) is used with the Ethernet option. The relay supports 10BaseT using
Cat 5 / Cat 5e shielded twisted pair. Refer to the BE1-700 Instruction Manual (9376700990) for further
details.
Detailed Message Query and Response
A detailed description of BE1-700 supported message queries and responses is provided in the following
paragraphs.
Read Holding Registers
This query message requests a register or block of registers to be read. The data block contains the
starting register address and the quantity of registers to be read. A register address of N will read holding
register N+1. If the query is a broadcast (device address = 0), no response message is returned.
Query
Device Address
Function Code =
03 (hex)
Starting Address Hi
Starting Address Lo
No. of Registers Hi
No. of Registers Lo
CRC Hi error check
CRC Lo error check
The number of registers cannot exceed 125 without causing an error response with the exception code
for an illegal function.