Novatech Bitronics M87X Series, Руководство пользователя

Страница: 95 / 184

ML0021 August 15, 2018
79
Copyright 2018 Bitronics, LLC
synchronization. If necessary, first increase the Max Skew setting
from 5
μ sec to 8 – 10 μ sec. If this does not help it may be necessary
to reduce the Quality Factor from 0.7 to 0.5 or less.
5.8 Time Sync & Setting
The 70 Series IED utilizes an on-board clock to time stamp communications, SOE Log
entries, and data samples in the Waveform, Disturbance, and Trend Recorders. A variety
of external references may be used to synchronize the on-board clock to either local or
Universal Coordinated Time (UTC) with a high degree of accuracy.
5.8.1 Time Sync Status Registers
Pre-defined status registers indicate the current state for each of the various time
synchronization methods used in 70 Series IEDs
The following time sync registers will return status values of ‘0’ if a time sync master is
inactive and ‘1’ if a time sync master is active:
Status Registers
IrigB Time Sync
Network Time sync
(UCA)
SNTP Time Sync
DNP Time Sync
The 70 Series DNP and Modbus manuals define the status register locations within
Appendix B for these time sync status points.
5.8.2 Manual time setting by Command-Line instruction
The command-line instruction is the manual method for setting the IED clock through
service port P1. The “time” instruction in the command-line interface is used to set time for
the IED’s internal clock. Refer to section 3.1.1a in order to set the IED clock.
5.8.3 Unsolicited DNP Time set (DNP master sets the IED clock)
DNP Time set is supported by the 70 Series IED. The IED clock simply free-wheels at its
characteristic rate between DNP time updates. Each DNP set-time instruction simply
"sets" the clock as it is received. Setting the clock via DNP supersedes any other time-
sync method that might be in use.
5.8.4 IRIG-B Time sync (time-synchronization via dedicated IED port)
Detailed information on IRIG-B time sync can be found starting in section 5.7. IRIG-B is
expected to produce the greatest accuracy relative to other time sync methods currently
supported. A status bit, named ‘IrigB Time Sync’, is set to indicate the IED is being
synchronized via IRIG-B as long as the IED continues to receive valid IRIG updates.
While this bit is set, time-sync signals received from
(UCA) Network Time Sync, SNTP,