Operating instructions

VLT
®
2800, VLT
®
6000 HVAC and VLT
®
8000 AQUA Modbus RTU
■ Appendix A - Examples
The following examples illustrate different
Modbus RTU commands.
In case of malfunction please refer to the
section Exception Codes.
■ EXAMPLE 1: Start Motor, Run Speed 40%
Modbus function 0F
HEX
(Force Multiple Coils).
Message sent to Modbus RTU from Modbus master
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
Slave
Address
Function Coil Addr HI Coil Addr
LO
No. of Coils
HI
No. of Coils
LO
Byte Count ForceDateHI
Coils (0-7)
01 0F 00 00 00 20 04 7C
Byte 8 Byte 9 Byte 10 Byte 11+12
Force Data
LO
Coils (8-15)
ForceDataHI
Coils (16-23)
Force Data
LO
Coils (24-31)
Error Check
04 99 19 [37] [43]
Modbus message string:
[01] [0F] [00] [00] [00] [20] [04] [7C] [04] [99] [19] [37] [43]
[7C]+[04]: Start Command: 0000010001111100 = 047C
HEX
(reversed)
(See Control Word Bit Descriptions)
Modbus message string:
[01] [0F] [00] [00] [00] [20] [04] [7C] [04] [99] [19] [37] [43]
[99]+[19]: NOTE: Speed Command: 4000
HEX
=100%speed
40% of 4000
HEX
= 1999
HEX
(reversed)
Message returned to Modbus master from Modbus RTU
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 + 7
Slave
Address
Function Coil Addr HI Coil Addr LO No. of Coils HI No. of Coils LO Error Check
01 0F 00 00 00 20 [54] [13]
All values are in hexadecimal.
■ EXAMPLE 2: Ramp Stop Motor
Message sent to Modbus RTU from Modbus master
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
Slave
Address
Function Coil Addr HI Coil Addr
LO
No. of Coils
HI
No. of Coils
LO
Byte Count ForceDateHI
Coils (0-7)
01 0F 00 00 00 20 04 3C
Byte 8 Byte 9 Byte 10 Byte 11+12
Force Data
LO
Coils (8-15)
ForceDataHI
Coils (16-23)
Force Data
LO
Coils (24-31)
Error Check
04 99 19 [89] [19]
MG.10.S2.02 - VLT is a registered Danfoss trademark
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