REAL conversion and numerical functions supply wrong results or lead to a CCr or Per TRIP (remedied from Vx.x)

Remedied from:
ECS axis module B-SW V6.7

Behaviour of new version?




Which products are affected?
ESP-DDS2-x (Global Drive PLC Developer Studio V2.x)
EPL-1020x (Drive PLC V6.x)
ECSxA (ECS axis module <=V6.6)

What happens?
  • Faulty results occur when converting data types such as REAL_TO_INT…
  • Faulty results or a CCr/PEr TRIP occur when executing numerical functions such as SIN, EXP, SQRT, …

When does the problem occur?
  • If one of the two functions L_MemReadDINT or L_MemReadDWORD is called up out of the LenzeMemDrv.lib or LenzeMemDrv0101.lib libraries a faulty result occurs when converting REAL data types to another data type (REAL_TO_xxx) in the same task.
  • If one of the two functions L_MemReadDINT or L_MemReadDWORD of the LenzeMemDrv.lib or LenzeMemDrv0101.lib libraries is called up and if in the same task numerical functions which require the REAL data type are executed the function indicates a faulty result or a CCr TRIP or Per TRIP occurs.

The target systems Drive PLC V1.x and V2.x are not affected by this function restriction since they do not support the LenzeMemDrv library.

Possible diagnostics?
Check by means of the DDS cross reference list (menu item: Project>Show Cross Reference) whether one of the functions L_MemReadDINT or L_MemReadDWORD is used in the project. Regarding this please select the POU category in the Cross Reference dialog.
If one of these functions is used in the project, check if data type conversions or numerical calculations are executed in the same task.

Short-term measures/recommendations?
Do not use the L_MemReadDINT or L_MemReadDWORD functions.

The revised LenzeMemDrv0102.lib library, with which this function restriction is eliminated, is installed when downloading Service Pack 1 of DDS V2.3. Replace the present LenzeMemDrv.lib or LenzeMemDrv0101.lib library by the new LenzeMemDrv0102.lib library in the Library manager dialog (menu item Window>Library manager).

Evaluation:
REAL_TO_xxx data type conversions and numerical functions requiring the REAL data type supply incorrect results or lead to a CCr TRIP / Per TRIP if one of the L_MemReadDINT or L_MemReadDWORD functions is executed in the same task. REAL calculations and REAL_TO_xxx data conversions must only be used in the cyclical task. The LenzeMemDrv library which contains the L_MemReadDINT and L_MemReadDWORD functions is used very rarely for the PLC target systems Drive PLC and ECS.

URL for linking this AKB article: https://www.lenze.com/en-de/go/akb/200506357/1/
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