800xA PLC Connect Alarm Event Configuration
Is it possible to trigger an alarm based on a true to false transition. I have a PLC Binary Signal Type object which is normally true and goes false when in alarm. I have attempted to configure the Alarm Event Configuration aspect for it to alarm when false but cannot get it to work. The alarm is only active when the value is true, another words true=alarm and false=normal. I need the opposite, true=normal and false=alarm. Because of the graphic state displayed in the faceplate for this object I cannot invert the logic, it must remain true=normal and false=alarm.
Thank you in advance.
Voted best answer
Alarm will be generated based on the true condition and it can not be generated based on the false condition. Becuase most of the input condition will be false during the normal operation. if you look oil and gas safety shutdown system-All digital inputs are normally energised contact and it will be useful to ensure the safety. I have inverted the logic in AC800M controller and generated the alarm based on true condition. So Invert your logic.