EcoStruxure Process Expert: Analog input instance shows wrong alarm in the genie and faceplate irrespective of the processed data.
Goals:
This Knowledgebase explains about the scenario where situational awareness Analog input instance shows the wrong alarm in the genie and faceplate irrespective of the processed data
Product Line:
This document is applicable for EcoStruxure Hybrid DCS 2019 and above versions
Procedure:
Sometimes it's been observed that the analog input instance from SA library shows the alarm irrespective of the processed data.
In the below example you can see that the Low limit and Low Low limit alarms are configured as 100, 200 respectively. But though the processed data is 400 the Low & Low Low alarms are high.
As per the $AnaloginputGP Library template design, when users generate the analog input instance AALARMGP DFB is also getting generated along with AINPUTGP DFB.
The AALARM is designed to show the alarm and all its functionality. The PV output pin of the AINPUTGP will be connected PV Input pin of the AALARMGP.
So, the data coming from the AINPUTGP will directly be given to AALARMGP act accordingly to show the alarms. By any chance, the link is missing (During refinement or by mistake user removes the pin) from these two pins causes an alarm generation according to the last value available in the PV pin of the AALARMGP DFBs.
In the below image you can see that the AINPUTGP Output PV pin got disconnected from the AALARMGP Input PV pin and the value has become “0“as there is no variable connected to the pin. The processed analog input value is showing as 400(Output pin PV of AINPUTGP DFBs) and the same value will be shown in the Genie and Faceplate of the Analog input instances as shown in the above pic. But the Low and Low Low alarm is getting generated as the input data for AALARMGP is 0.If user connect pin again will resolve the concern