BACnet/IP Controller 750-830
•
71
Data Exchange
WAGO-I/O-SYSTEM 750
BACnet/IP Controller
Calculating addresses (as a function of the word address):
Bit address:
Word address .0 to .15
Byte address:
1st byte: 2 x word
2nd byte: 2 x word a 1
DWord address
Word address (even number) / 2 or
Word address (uneven number) / 2, rounded
3.1.6.3 Data Exchange between MODBUS/TCP Master and Bus Modules
Data exchange between the MODBUS/TCP master and the bus modules is con-
ducted using the MODBUS functions implemented in the controller by means
of bit-by-bit or word-by-word reading and writing routines.
There are four (4) different types of process data in the controller:
•
Input words
•
Output words
•
Input bits
•
Output bits
Access word-by-word to the digital I/O modules is carried out in accordance
with the following table:
Tab. 3-14: Allocation of digital inputs and outputs to process data words in accordance with
the Intel format
Digital inputs/
outputs
16. 15. 14. 13. 12. 11. 10. 9. 8. 7. 6. 5. 4. 3. 2. 1.
Process Data Word
Bit
15
Bit
14
Bit
13
Bit
12
Bit
11
Bit
10
Bit
9
Bit
8
Bit
7
Bit
6
Bit
5
Bit
4
Bit
3
Bit
2
Bit
1
Bit
0
High-byte Low-byte
Byte
D1 D0
Output can be read back in by adding an offset of 200
hex
(0x0200) to the
MODBUS address.
Note
All output data greater than 256 words and, therefore located in the memory
range 0x6000 to 0x62FC, can be read back by adding an offset of 1000
hex
(0x1000) to the MODBUS address.
