Balluff BIS M-370-000-A02, Manual, Page: 123 / 198

BIS M-62_ MANUAL
116
8
8.2.4 DeviceNet - Exchanging Data and Handshaking
After the Controller has been properly configured for your DeviceNet network, it will be
possible to send the Controller commands using the Balluff
CBx Command Protocol . For
reference, the CBx Command Protocol Reference Manual is available on the Balluff Web site
(www.balluff.com).
However, to ensure that messages to and from the Controller are properly delivered and
received, a handshaking mechanism has been implemented that uses a pair of dedicated
words in the exchange.
The first two words in the
Input Controller Tag and Output Controller Tag are dedicated to
handshaking. When new information is generated, the data-producing device increments the
counter value stored in the second word of a controller tag (either Input or Output, depending
on the device). The data-consuming device, copies that same value to the counter in the first
word of the reciprocal (or opposite) controller tag. This handshaking scheme signals to the
data producer that the information has been received.
The image below displays an example of the data contained in the two I/O Controller Tags
for the Controller.
Figure 65 - Controller I/O Controller Tags (in RSLogix 5000)