Multi-Tech Systems 7500, 7600 manual Clock Module Settings, Clock Source Used for Synchronization

ION 7500 / ION 7600 User’s Guide Clock Module Settings

Clock Module Settings

The Clock module controls an ION meter’s internal clock. In order to correctly set up time synchronization with your single meter or network, you need to be familiar with certain features of the Clock module. Essentially, you need to configure the Clock module’s Setup registers to correspond to the type of time synchronization you desire. You use Designer software or the front panel’s Setup menu to configure the Clock module.

Clock Source Used for Synchronization:

The Clock Source setup register has three settings from which to choose, depending on the method of time synchronization. The ION 7500 / ION 7600 and ION 8000 Series of meters have all three settings available as options. The ION 7700 and ION 7300 Series only have the INTERNAL setting.

LINE FREQUENCY:

When the Clock Source is set to monitor the ISO Grid Operation line frequency, each meter auto-corrects the internal clock based on the measured line frequency. Over a long period of time, this form of time keeping is highly accurate. If a power outage occurs, the clock automatically synchronizes with the meter’s internal crystal until power is restored. Once the power is restored, the clock once again synchronizes with the line frequency. Meters synchronize with the line frequency by default.

INTERNAL:

If you prefer having the meter itself provide timekeeping, set the Clock Source setup register to INTERNAL. The clock then synchronizes to the meter’s internal crystal.

COMM:

Use this for the Clock Source if you set the Sync Source setup register (see below) to a COM port to receive GPS time synchronization signals.

Type of Time Used for Synchronization:

The Time Sync Type setup register specifies whether time synchronization signals are received in Coordinated Universal Time (UTC) or Local Time.

UTC:

Coordinated Universal Time is the standard time common to every place in the world. Formerly and still widely called Greenwich Mean Time (GMT), UTC nominally reflects the mean solar time along the Earth's prime meridian. It is expressed using a 24-hour clock but can be converted into a 12-hour clock (AM and PM). The time kept on the ION meter is always UTC (24-hour clock). When using UTC, the TZ Offset and DST Offset setup registers (see below) are not required. The Time Sync Type setup register is set to UTC by default.

LOCAL:

This setting requires that the time zone offset and DST offset are filled in correctly. Thus, Local time is basically the UTC adjusted for time zone and daylight savings time. There are some DNP masters and GPS receivers that use Local time; for these only, change the Time Sync Type from its default setting to LOCAL.

Time Synchronization & Timekeeping Technical Note Page 349