Operating Instructions

Chapter 4 - Parameters and Menu Structure
I/O and Hardware (M5)
156 | 187
Siemens Industry, Inc.
Siemens BT300 HVAC Drive
DPD01809
Smart Infrastructure
2019-05-29
Command Master - Slave:
ADDRESS
01 hex Slave address 1 hex (= 1)
FUNCTION
04 hex Function 4 hex (= 4)
DATA
Starting address HI
08 hex
Starting address LO
36 hex
No. of registers HI
00 hex Number of registers 0002 hex (= 2)
No. of registers LO
02 hex
ERROR
CRC HI
93 hex CRC field 93A5 hex (= 37797)
CHECK
CRC LO
A5 hex
Message frame:
01
04
08
36
00
02
93
A5
The reply to the Read Input Registers message contains the values of the read registers.
Answer Slave - Master:
ADDRESS
01 hex Slave address 1 hex (= 1)
FUNCTION
04 hex Function 4 hex (= 4)
DATA
Byte count
04 hex Byte count 4 hex (= 4)
Data HI
13 hex Speed reference = 1388 hex (= 5000 = > 50.00%)
Data LO
88 hex
Data HI
09 hex Output Frequency = 09C4 hex (= 2500 = >25.00 Hz)
Data LO
C4 hex
ERROR
CRC HI
78 hexCRC field 78E9 hex (= 30953)
CHECK
CRC LO
hex
Reply frame:
01
04
04
13
88
09
C4
78
E9
Example of an exception response
In an exception response, the Slave sets the most-significant bit (MSB) of the function code to 1. The Slave
returns an exception code in the data field.
Command Master - Slave:
ADDRESS
01 hex Slave address 1 hex (= 1)
FUNCTION
04 hex Function 4 hex (= 4)
DATA
Starting address HI
17 hex Starting address 1770 hex (= 6000)
Starting address LO
70 hex