Modbus Protocol

Strona
3 z 10
1. Revision history
Version Date Author Description
1.1 18.09.2020 BTR Updated: Read Events, Read Parameter Chart, Read Battery Temperature
Chart
1.0 04.04.2019 BTR Initial release
2. Modbus protocol
The Modbus protocol is an industrial communication protocol that is currently used in EN54C-LCD. The power
supplies use two type of connections:
• RS-485 - Modbus RTU – Default settings: Address: 1, Baud Rate: 9600 bps, 8E1
• TCP/IP - Modbus TCP/IP – Default settings: IP: 192.168.1.100, Port: 502
For more information about the Modbus protocol refer to the following application notes:
• Modbus_over_serial_line_V1_02.pdf
• Modbus_Application_Protocol_V1_1b.pdf
• Modbus_Messaging_Implementation_Guide_V1_0b.pdf
3. Function codes
The following Modbus function codes are supported by the implemented protocol:
Public function Codes
Read Input Registers 04 (0x04)
User defined function Codes
Service 65 (0x41)
Read Events 66 (0x42)
Read Parameter Chart 67 (0x43)
Read Battery Temperature Chart 68 (0x44)
3.1. Public function codes - Read Input Registers (0x04)
Register
address
Register description Function description Position Type Format Comments
3100-3103
LCD panel - serial
number
Data 1 3100: 15…0 uint16_t 2 – EN54C
Hex format
(xx-xxxx-xx-
xxxx)
Data 2 3101: 15…0 uint16_t
Data 3 3102: 15…0 uint16_t
Data 4 3103: 15…0 uint16_t
3104-3106
LCD panel - software
version
Major 3104: 15…0 uint16_t
Dec format
(d.d.d)
Minor 3105: 15…0 uint16_t
Release 3106: 15…0 uint16_t
3107-3110
Power supply - serial
number
Data 1 3107: 15…0 uint16_t
4 – version 2A
5 – version 3A
6 – version 5A
7 – version 10A
Hex format
(xx-xxxx-xx-
xxxx)
Data 2 3108: 15…0 uint16_t