4 Modbus/TCP
4-4 Ethernet Option Board /
700.002 735 AE01
4.4 Input Discrete (1x)
Both the 'Coil register' and the 'Input discrete register' contain binary data. However, the difference between
the two registers is that the Input register's data can only be read. The Converteam Ethernet board's
MODBUS/TCP implementation uses the following Input discrete addresses.
4.4.1 10001 – 1008, Status Word (Read Only)
Address Name 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 Warning 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
10009- Manufacturer reserved
Table 4-7: Status Word Structure
The following tables show a MODBUS query that reads the entire status word (8 input discretes) and the
query response.
Query:
0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x01, 0x02, 0x00, 0x00, 0x00, 0x08
Data Purpose
0x00 Transaction ID
0x00 Transaction ID
0x00 Protocol ID
0x00 Protocol ID
0x00 Length
0x06 Length
0x01 Unit identifier
0x02 Read input discrete
0x00 Reference number
0x00 Reference number
0x00 Bit count
0x08 Bit count
Table 4-8: Status Word Read - Query
Response:
0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x01, 0x02, 0x01, 0x41
Data Purpose
0x00 Transaction ID
0x00 Transaction ID
0x00 Protocol ID
0x00 Protocol ID
0x00 Length
0x04 Length
0x01 Unit identifier
0x02 Read input discrete
0x01 Byte count
0x41 Data
Table 4-9: Status Word Read - Response