User`s manual

Western Reserve Controls 1782-JDM User’s Manual

PUB 24.0

Table 5-2 I/O Assembly Object Instance 2 Data Format – Short Command w/o Fragmentation

Byte

(Offset value)

Data

0 Record number

1 Length

2 Address

3 Command

4 Data www – LSB

5 Data www – MSB

6 Data xxx – LSB

7 Data xxx – MSB

5.2 Input Data, ModBus Response

The exact format of the input data that is received at your DeviceNet master is defined by the

ModBus command used. The following tables provide the general format and illustrate the differences

between the ASCII and RTU modes. Review the ModBus spec or your ModBus device’s user’s manual for

more details.

Table 5-3 I/O Assembly Object Instance 1 Data Format – Response

Byte

(Offset value)

Data

0 Record number

1 Status

2 Length

3 Address

4 Function/Command

5 Byte Count

6 Data xxx - LSB

7 Data xxx - MSB

8 Data yyy - LSB

9 Data yyy - MSB

…

N Last data - LSB

N + 1 Last data - MSB

For the input assembly to the host, the user does not need be concerned with differentiating between

fragmented and non-fragmented messages. The JDM and the host processor will do this transparently.