BASEstar^tm Classic DAS
for Allen-Bradley
INTERCHANGE^tm Software
Installation and User's Guide

BASEstar Classic device connection management physical points may be grouped together into pollsets to optimize data collection. Pollsets created for the Allen-Bradley devices have the following limitations:

• Physical points of differing data types cannot be part of the same pollset. For example, a physical point of type WORD and a physical point of type BIT cannot be members of the same pollset. Physical points of the same data type with varying element counts can reside in the same pollset.
• The maximum solicited read/write operation is 2048 bytes for local PLC-5/250 or PLC-5/XXE devices or 242 bytes for devices connected to a Pyramid Integrator via Data Highway. The size of any pollset cannot exceed these maximum contiguous bytes limits, regardless of the number of physical points in the pollset. Therefore, the first byte of the physical point with the lowest address cannot be more than the maximum bytes away from the last byte of the physical point with the highest address.
• Points that are defined as format structure can be polled, provided that the structures of all the points in the pollset are identical.
• Members of pollsets created for PLC-5, SLC or PLC-3 families must have identical file types and file numbers.
• PLC-5/250 pollsets members must have identical module numbers.
• PLC-3 pollsets members must have identical contexts and must be the data table subarea.

For more information on physical points, refer to the BASEstar Classic Command Line Interface User's Guide.