Modbus Protocol

Strona 3 z 6
1. Revision history
Version
Date
Author
Changes
1.0
1.06.2017
BTR
Initial release
1.1
15.01.2017
BTR
Added Write Multiple Registers
2. The Modbus Protocol
The Modbus Protocol is an industrial communication protocol that is currently used in EN54 Power Supplies.
The Power Supplies use two type of connections:
 RS-485 - Modbus RTU (115200 kbps, 8E1 – default settings)
 TCP/IP - Modbus RTU over TCP (See the instruction of the appropirate interface: INTE, INTW)
3. Function codes
The following Modbus function codes are supported by the implemented protocol:
Function code
Dec
Read Input Registers
04
Write Multiple Registers
16
4. Read Input Registers
Register
address
Register description
Function description
Position
Type
Format
Access
00
Firmware version and
power supply version
Firmware version
7…0
uint8_t
v1.0 is equal to 10
R
Power supply type
11…8
4-bit
0 – PSBEN
1 – EN54
03
Error flags (1)
F18 - High battery
circuit resistance
0
1-bit
0 – inactive
1 – active
R
F16 - No battery
2
1-bit
0 – inactive
1 – active
F02 - AUX2 fuse fail
3
1-bit
0 – inactive
1 – active
F61 - Internal supply
fail
4
1-bit
0 – inactive
1 – active
F06 - High AUX2
voltage
5
1-bit
0 – inactive
1 – active
F09 - Low AUX2
voltage
6
1-bit
0 – inactive
1 – active
F14 - Temperature
sensor fault
8
1-bit
0 – inactive
1 – active