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What is the time drift for the SEPAM Relays?

The SEPAM relays are not always time synced using GPS or SNTP, so the time depends on the SEPAM internal clock.  If the internal clock is relied on then what is the time drift of the SEPAM?

Product Line       
SEPAM 20, 40, 50, 60, & 80

Time synchronization

All internal clocks on the SEPAMs have the ability to drift, which causes the SEPAMs not to have the accuracy time on the device.

Below are details of the RTC (Real Time Clock) used inside Sepam relays:
  • The global accuracy of Sepam RTC is 5 ppm at 25°C
  • The used quartz has an accuracy of 20 ppm at 25°C
  • This leads to a global accuracy error of 25 ppm
The SEPAMs time accuracy drift without any time synchronization is 25ppm (parts per million) at normal operating temperature range stated in the manual.

This means in one day the drift would be 25ppm * 3600 * 24 = 2.16 seconds.  In a year drift time will be 13.14 minutes.

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