Reading N Words; Data Query; Writing 1 Word - Siemens RS-485 User Manual

Reading n words

Data query

Reply
Example

Writing 1 word

Instruction
Reply
Example
Siemens Building Technologies
HVAC Products
This function is used to read n words from a certain address.
Slave address Function 0x03
or 0x04
1 byte 1 byte
Slave address Function 0x03
or 0x04
1 byte 1 byte
Reading the 2 setpoints of the controller
Word address = 0x0008 (setpoint SP1)
Data query:
0B 03
Reply:
0B 03
With the "Wordwriting" function, the data blocks for instruction and reply are identical.
Slave address Function 0x06
1 byte 1 byte
Slave address Function 0x06
1 byte 1 byte
Write limit value limit comparator 1 (AL1) (= 275)
Word address = 0x000C
Instruction: (write the first part of the value)
0B 06
Reply (like instruction):
0B 06
Instruction: (write the second part of the value)
0B 06
Reply (like instruction):
0B 06
Address of the
first word
2 bytes
Number of
bytes read
1 byte
00 08
08 0000 42C8
Setpoint 1 (100)
Word address
2 bytes
Word address
2 bytes
00 0C
00 0C
00 0D
00 0D
Number of Checksum
words CRC16
(max. 12)
2 bytes 2 bytes
Word value(s) Checksum
CRC16
x byte(s) 2 bytes
00 04
0000 4316
Setpoint 2 (150)
Word value Checksum
CRC16
2 bytes 2 bytes
Word value Checksum
CRC16
2 bytes 2 bytes
80 00
80 00
43 89
43 89
CC1A7865.1en
CRC16
CRC16
CRC16
CRC16
CRC16
CRC16
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31.10.2002