Applies To:
  • CitectSCADA 5.xx
  • CitectHMI 5.xx
Summary:
A Control Logix project has an array of structures defined. When attempting to access element zero (0) of the array, the ABLOGIX driver could not read or write to this element. However, accessing other elements in the same array were successful.

Consider a tag defined in the PLC as "AshAnoAnmAno02ActDay", defined as an array of structures. In Citect, I have defined a tag with address "AnoAnmAnode02.date_action[0]". I cannot read or write to element 0 of an array that is part of a structure. I can access other elements of the same array (eg AnoAnmAnode02.date_action[1]) without any errors.

 

Solution:
The problem is due to the way the ABLOGIX driver interprets the meaning of the square brackets "[ ]" used in the addressing scheme. The "[ ]" brackets are used in the driver to denote the size of an array and not to be used as an access index into an array. To access an index of an array, use the "{ }" brackets instead.

Thus, to access an element of an array, you will need to define your Citect tags as:

i. "AnoAnmAnode02.date_action{0}", or

ii. "AnoAnmAnode02.date_action{0}.pump".

 
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