Numerical overflow of REAL variables does sporadically not activate a trip

Which products are affected?
EPL-10200 (Drive PLC V7.2 and lower)
EVS93xxEI (Servo PLC V7.2 and lower)
EVS93xxET (Servo PLC with technology function V7.2 and lower)
ECS axis module: ECSxx operating software V7.4 and lower

What happens?
The PLC target system is stopped without any error message.

When does the problem occur?
If a numerical overflow occurs in case of calculations with REAL data type variables a trip is sporadically not activated. If available the PLC_RealError POU is executed before the PLC target system is stopped.

Possible diagnostics?
None.

Short-term measures/recommendations?
Add PLC_RealError POU to your PLC project and set an error bit inside the added POU. The POU is executed automatically whenever the PLC target system detects an error in REAL calculations.

Evaluation:
If a counter numerical is detected in case of REAL calculations, the PLC target system is stopped. However, there is sporadically no trip activated and as a result the defined exceptional response for the drive is not executed. This means if this function restriction occurs while an axis is moved, the axis movement cannot be stopped by the PLC target system.

URL for linking this AKB article: https://www.lenze.com/en-de/go/akb/200801476/1/