She also notes that you need to clean and calibrate them daily, especially the electrodes.
Vinquiry has a specialist come in once a year to clean, adjust and calibrate its microscopes.
Vinquiry uses both hand-held and laboratory-based Anton Paar densitometers; the supplier's representative visits to maintain and calibrate the equipment.
"We can calibrate the hand-held unit ourselves if we carefully follow the directions in the manual," she says.
NIST does not have the facilities to calibrate large natural gas meters on its sites in Maryland and Colorado, so it rents facilities from a qualified commercial vendor of calibration facilities, the Colorado Engineering Experiment Station Inc.
The parallel array of venturis was used to calibrate larger venturis, one at a time.