You can add High/Low lines to graph by using the Formula Sensors Features of the Loadvue Software family.

Click on Sensors...Formula Sensors...



Then add a formula sensor with a constant value. For example, if upper limit is 20 lb,

Select

Name: High
Formula: 20
Units: lb

Click ok. The program will restart and the new formula sensors will be added to the list of sensors available to be graphed. Right click on the Graph, Select Graph Options and add the formula sensors to be graphed.

Now, when start reading the sensors, the formula sensors will show up as high/low lines