While a vessel or reactor is being charged, you can compare DELTA M switch point indications to any continuous unit’s output. The DELTA M switch indicating points can’t change once installed making them very reliable as backups to other forms of level measurement. Example: When charging a critical reactor, the operator or, in many cases, the control system compares our switch point indications to the output from the continuous level instrument. If they agree, charge continues. If not, the reaction is aborted and a possibly serious accident is prevented.