Rockwell Automation 2711 PanelView 550/900 Profibus Communications User Guide - Manual (Page 27)

PROFIBUS DP Communications 27
Publication 2711-6.3
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ATTENTION: When assigning tags, make sure that
the PanelView input tag addresses do not overlap. If
two tags overlap the same block location, unpredictable
data will be sent to the DP Master.
The following are examples of common addressing errors:
Example 1
Tag Tank_temp is a floating point value at PI3:2 and tag
Tank1_level is an unsigned integer at address PI3:3. These
addresses overlap and the data entered by the operator that is sent
to these addresses will not be correct.
Example 2
Tag Fill_level is an unsigned integer at address PI0:2, tag
Tank2_level is also an unsigned integer at PI0:2. The value read
by the PLC will not be what is expected. The address will always
contain data from one or the other tag, it is not possible to predict
which one.
Example 3
Tag Tank3_control is a Bit Array with a length of 3 at address
PI123:3/2 and tag Tank3_empty is a bit tag at PI123:3/3. Only
one of these tags will have the correct value, but not both.
Example 4
Tag Tank4_fill is a bit tag at address at PI12:15/2 and tag
Fill_level is a signed integer at address PI12:15. Again, only one
of these tags will have the correct value, but not both.
In some cases overlapping addresses may appear to function
correctly (for example if the tag content is 0). Use the PanelBuilder
tag attribute report function to check for overlapping addresses.
Overlapping Input Tags