9440300990 Rev J
179
DECS-250
Timekeeping
Timekeeping
The DECS-250 clock is used by the logging functions to timestamp events. DECS-250 timekeeping can
be self-managed by the internal clock or coordinated with an external source through a network or IRIG
device.
BESTCOMS
Plus
®
Timekeeping settings are shown in Figure 157.
BESTCOMSPlus Navigation Path:
Settings Explorer, General Settings, Clock Setup
HMI Navigation Path:
Settings, General Settings, Clock Setup
Time and Date Format
Clock display settings enable you to configure the time and date reported by the DECS-250 to match the
conventions used in your organization/facility. The reported time can be configured for either the 12- or
24-hour format
A
with the Time Format setting. The Date Format setting
A
configures the reported date for
one of three available formats: MM-DD-YYYY, DD-MM-YYYY, or YYYY-MM-DD.
Daylight Saving Time Adjustments
The DECS-250 can automatically compensate for the start and end of daylight saving time (DST) on a
fixed- or floating-date basis
B
. A fixed-date, for example, is March 2, and an example of a floating-date is,
“Second Sunday of March”. DST compensation can be made in respect to your local time or coordinated
universal time (UTC)
C
. DST start
D
and end
E
points are fully configurable and include a bias adjustment
F
.
Network Time Protocol (NTP)
When connected to an Ethernet network, the DECS-250 can use NTP to assure accurate, synchronized
timekeeping. By synchronizing with a radio, atomic, or other clock located on the internet/intranet, each
DECS-250 maintains accurate timekeeping that is coordinated with the time source.
NTP Settings
NTP is enabled in the DECS-250 by entering the internet protocol (IP) address of the network timeserver
in the four decimal-separated fields of the NTP Address setting
G
. Time zone offset settings
H
provide the
necessary offset from the coordinated universal time (UTC) standard. Central standard time is six hours
and zero minutes behind (–6, 0) UTC and is the default setting.
The Time Priority Setup must be used to enable a connected time source. When multiple time sources
are connected, the Time Priority Setup
I
can be used to rank the sources according to their priority.
IRIG
When the IRIG source is enabled, through the Time Priority Setup, it begins synchronizing the DECS-250
internal clock with the time code signal.
Some older IRIG receivers may use a time code signal compatible with IRIG standard 200-98, format
B002, which does not contain year information. To use this standard, select the
IRIG without Year
radio
button in the
IRIG Decoding
box
J
. Year information is stored in nonvolatile memory so the year is retained
during a control power interruption.
The IRIG input accepts a demodulated (dc level-shifted) signal. For proper recognition, the applied IRIG
signal must have a logic high level of no less than 3.5 Vdc and a logic low level that is no higher than 0.5
Vdc. The input signal voltage range is –10 Vdc to +10 Vdc. Input resistance is nonlinear and
approximately 4 k
Ω at 3.5 Vdc and 3 kΩ at 20 Vdc. IRIG signal connections are made at terminals IRIG+
and IRIG– which are located on the right side panel.
Summary of Contents for DECS-250
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Page 6: ...iv 9440300990 Rev J Revision History DECS 250 ...
Page 16: ...xiv 9440300990 Rev J Contents DECS 250 ...
Page 20: ...4 9440300990 Rev J Introduction DECS 250 ...
Page 28: ...12 9440300990 Rev J Power Stage DECS 250 ...
Page 32: ...16 9440300990 Rev J Voltage and Current Sensing DECS 250 ...
Page 40: ...24 9440300990 Rev J Synchronizer DECS 250 ...
Page 52: ...36 9440300990 Rev J Auxiliary Control DECS 250 ...
Page 56: ...40 9440300990 Rev J Contact Inputs and Outputs DECS 250 ...
Page 84: ...68 9440300990 Rev J Limiters DECS 250 ...
Page 114: ...98 9440300990 Rev J Power System Stabilizer DECS 250 Figure 96 PSS Parameter Settings ...
Page 124: ...108 9440300990 Rev J Stability Tuning DECS 250 ...
Page 126: ...110 9440300990 Rev J Mounting DECS 250 Figure 103 Overall and Projection Mounting Dimensions ...
Page 127: ...9440300990 Rev J 111 DECS 250 Mounting Figure 104 DECS 250 Escutcheon Plate Dimensions ...
Page 198: ...182 9440300990 Rev J Timekeeping DECS 250 ...
Page 210: ...194 9440300990 Rev J CAN Communication DECS 250 ...
Page 304: ...288 9440300990 Rev J Maintenance DECS 250 ...
Page 316: ...300 9440300990 Rev J Specifications DECS 250 ...
Page 334: ...318 9440300990 Rev J Analog Expansion Module DECS 250 ...
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