Specification of clock accuracy for the ION7x50 and ION86X0.
Issue
Customer would like to know the clock accuracy of the ION7x50 and ION86x0 devices
Product Line
ION7550
ION7650
ION8600
ION8650
Environment
Meter Configuration
Cause
Clock accuracy is due to the internal crystal tolerance (up to ±10 ppm).
Resolution
ION7x50 and ION86X0 use the same internal crystal, the specification for the accuracy of the internal crystal
1, +/-5ppm typical (at 0degC-40degC)
2, +/-10 ppm max (at -20degC-70degC)
PPM is parts per million, 0.0001%. In terms of second per day, 12 PPM corresponds to one second per day roughly. This means the internal crystal in those meters lose less than one second per day in the worst case and typically loses around a half second per day or 15 second per month.