Operating Instructions

Chapter 4 - Parameters and Menu Structure
I/O and Hardware (M5)
148 | 187
Siemens Industry, Inc.
Siemens BT300 HVAC Drive
DPD01809
Smart Infrastructure
2019-05-29
Function
Code
Modbus Function Name
TCP/RTU
Access
Type
Address Range
(hex)
6 (0X06)
Write Single Register
TCP&RTU
16bit
40000 - 4FFFF
15 (0X0F)
Write Multiple Coils
TCP only
Discrete
00000 - 0FFFF
16 (0X10)
Write Multiple Registers
TCP&RTU
16bit
40000 - 4FFFF
23 (0X17)
Read/Write Multiple Registers
TCP&RTU
16bit
40000 - 4FFFF
NOTE:
Broadcasting is not supported in TCP. Broadcast is supported with function codes
06 and 16 in RTU.
Modbus Data Mapping
Coil registers
Coil registers contain binary data (Read/Write). For more information, see Control word bits in this chapter.
Table 110: Defined Modbus Coil Registers.
Address
Function
Purpose
0001
RUN/STOP
Control Word, bit 0.
0002
Direction
Control Word, bit 1.
0003
Fault reset
Control Word, bit 2.
Discrete inputs
Input discrete registers contain binary data (Read). For more information, see Status word bits in this chapter.
Table 111: Defined Modbus Discrete Inputs.
Address
Function
Purpose
10001
Ready
Status Word, bit 0.
10002
Run
Status Word, bit 1.
10003
Direction
Status Word, bit 2.
10004
Fault
Status Word, bit 3.
10005
Alarm
Status Word, bit 4.
10006
At reference
Status Word, bit 5.
10007
Zero speed
Status Word, bit 6.
10008
Flux ready
Status Word, bit 7.
Holding registers and input registers
All values can be read with function codes 3 and 4 (all registers are 3X and 4X reference).The Modbus
registers are mapped to the Siemens BT300 Drive as follows: