P44x/EN SC/Hb
P442, P444 (SC) 12-
5.5 Object 20 binary counters
Object 20, binary counters, contains cumulative counters and measurements. The binary
counters can be read as their present ‘running’ value from object 20, or as a ‘frozen’ value
from object 21. The running counters of object 20 accept the read, freeze and clear
functions. The freeze function takes the current value of the object 20 running counter and
stores it in the corresponding object 21 frozen counter. The freeze and clear function resets
the object 20 running counter to zero after freezing its value.
5.6 Object 30 analog input
Object 30, analog inputs, contains information from the relay’s measurements columns in the
menu. All object 30 points are reported as fixed-point values although they are stored inside
the relay in a floating-point format. The conversion to fixed-point format requires the use of a
scaling factor, which differs for the various types of data within the relay e.g. current, voltage,
phase angle etc. The data types supported are listed at the end of the device profile
document with each type allocated a ‘D number’, i.e. D1, D2, etc. In the object 30 point list
each data point has a D number data type assigned to it which defines the scaling factor,
default deadband setting and the range and resolution of the deadband setting. The
deadband is the setting used to determine whether a change event should be generated for
each point. The change events can be read via object 32 or object 60 and will be generated
for any point whose value has changed by more than the deadband setting since the last
time the data value was reported.
Any analog measurement that is unavailable at the time it is read will be reported as offline,
e.g. the frequency when the current and voltage frequency is outside the tracking range of
the relay or the thermal state when the thermal protection is disabled in the configuration
column. Note that all object 30 points are reported as secondary values in DNP3.0 (with
respect to CT and VT ratios).
5.7 DNP3.0 configuration using MiCOM S1 Agile
A PC support package for DNP3.0 is available as part of the settings and records module of
MiCOM S1 Agile . The S1 module allows configuration of the relay’s DNP3.0 response. The
PC is connected to the relay via a serial cable to the 9-pin front part of the relay – see
Introduction (P44X/EN IT). The configuration data is uploaded from the relay to the PC in a
block of compressed format data and downloaded to the relay in a similar manner after
modification. The new DNP3.0 configuration takes effect in the relay after the download is
complete. The default configuration can be restored at any time by choosing ‘All Settings’
from the ‘Restore Defaults’ cell in the menu ‘Configuration’ column. In S1, the DNP3.0 data
is displayed on a three-tabbed screen, one screen each for object 1, 20 and 30. Object 10 is
not configurable.
5.7.1 Object 1
For every point included in the device profile document there is a check box for membership
of class 0 and radio buttons for class 1, 2 or 3 membership. Any point that is in class 0 must
be a member of one of the change event classes 1, 2 or 3.
Points that are configured out of class 0 are by default not capable of generating change
events. Furthermore, points that are not part of class 0 are effectively removed from the
DNP3.0 response by renumbering the points that are in class 0 into a contiguous list starting
at point number 0. The renumbered point numbers are shown at the left-hand side of the
screen in S1 and can be printed out to form a revised device profile for the relay. This
mechanism allows best use of available bandwidth by only reporting the data points required
by the user when a poll for all points is made.
5.7.2 Object 20
The running counter value of object 20 points can be configured to be in or out of class 0.
Any running counter that is in class 0 can have its frozen value selected to be in or out of the
DNP3.0 response, but a frozen counter cannot be included without the corresponding
running counter. As with object 1, the class 0 response will be renumbered into a contiguous
list of points based on the selection of running counters. The frozen counters will also be
renumbered based on the selection; note that if some of the counters that are selected as
running are not also selected as frozen then the renumbering will result in the frozen
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