46
ICC
Figure 16: Modbus - DeviceNet Little Endian
In contrast, Figure 17 shows the effects of configuring the database for big-
endian byte order. Holding registers 1 and 2 again have values of 0x1234 and
0x5678, respectively. However, when the DeviceNet device receiving the input
data from the gateway interprets these values, the resulting pairs of 2-byte
values become 0x3412 and 0x7856, thus receiving incorrect values for holding
registers 1 and 2. Note that in both examples, the DeviceNet network data is
always identical, byte-for-byte, to the gateway’s database. For this reason it is
important to configure gateways that use a bag-of-bytes style network, such as
the DNET-1000, to use the same endianness as defined for that network.
Figure 17: Modbus - DeviceNet Big Endian
12.3
BACnet - DeviceNet Example
This example is quite similar to the previous one as data is exchanged between
an object-value style network (BACnet) and a bag-of-bytes style network
(DeviceNet). The key difference is that in this example, BACnet Analog Value 0
is a 32-bit value, as opposed to two 16-bit Modbus registers. Here, the gateway
