Test whether one value is greater than the second value.
Let's say we have a HPU system that we are monitoring its oil temperature. When the temperature of the oil is greater than 120 degree Celsius, we want to send a warning and start the fan to cool down the oil.
Ladder Logic Solution
- Temperature I:1.0
- Fan O:2.0/0
- HPU auxiliary I:3.0/0
- HPU Warning B3:0/0
While the HPU is running if the temperature gets higher than 120 degree then the fan will start and a warning will be set to on.
- Usually the warning is sent to a human interface in the form of an alarm to warn the user that the temperature is too high and should be somehow cooled down.