User`s manual

Watlow EZ-ZONE™ Communications • 51 • Chapter 4 DeviceNet
A user may want to monitor the status of these bits in the PLC program. If either of these bits goes to "0",
communications have failed between the DeviceNet card and the PM
Taking a closer look at previous work, specifically, where the PM was mapped into PLC memory via the
scanners scanlist (RSNetWorx) we can see below in figure 4.19 and 4.20 a direct correlation between the PLCs
controller tags (screen shot below) and figure 4.13. In the addresses circled below in figure 4.19 notice that
from the PLCs perspective that the scanner is identified as sitting in slot 1 and the "I" indicates inputs which
represents, in this case, the default T to O assembly from the PM. In figure 4.20 we see the same relationship
for the O to T assembly which represents data sent from the PLC to the PM..
Figure 4.20
Notice that in figure 4.19 above that there is data coming in to the PLC delivered by the PM, this is with-
out any programming! In figure 4.20 we can also see that since there is no program in the PLC that there is
no data being sent to the PM. Lets take a closer look at some simple programming so that we can send data
from the PLC to te PM.
Figure 4.19