All charts that have the ability to show you when a value has breached a configured Limit provide a property on the measure to choose the respective Limit.
Once a Limit has been configured, you also need to tell the Flow Server to actually do something when it find a measure value with an Exception. Usually, you want to change the color of the value. This is done by adding a "Limit Color Provider" by right-clicking on the Color Property, then Add > Limit Color Provider
See the following article: