Limits

The Limit FirstSite analytic goes through your ARDI system and checks for any properties that include the word maximum or minimum in their name.

If found, it then searches the assets that use that property (and any assets that are either downstream or upstream from them in your Location hierarchy) for a matching measurement.

If found, the values are then compared to ensure that your system is running within the specified limits.

The UI for sequence tests is explained here.

A single asset might have several different limits across a range of properties. Although FirstSite will try a number of different combinations of name when searching for your real measured value, we suggest 'Maximum' or 'Minimum' being the first word of the property name.

For example, if you wanted to measure and set limits to your Instrument Air pressure…

You can also place the 'Maximum' or 'Minimum' text at the start of the name of the media type -

As well as running through FirstSite, your limit analytics can be deployed as a live alert.

There can be some unexpected cases where you get a false match from FirstSite.

One example is machines that have several parts that run at different speeds, but don't monitor them all.

ARDI might go looking for a speed measurement for Part A and end up using the measured speed of Part B instead.

In these cases, we'd suggest (in order of preference)

• Measuring the correct value for the component,
• Calculating or modelling the value for the component,
• Adjusting your Location hierarchy to prevent the connection,
• Removing the limits from the ARDI database,
• Ignoring the FirstSite status.

We generally consider the analytic reporting 'bad' on a false match to be a positive thing. It's informing you that you're missing a key measurement that might be relevant to the well-being of your system.