GE 489 User Manual
Page 212
6-50
489 Generator Management Relay
GE Multilin
6.5 DNP POINT LISTS
6 COMMUNICATIONS
6
TABLE NOTES:
1.
Unless otherwise specified, an event object will be generated for a point if the current value of the point changes by an
amount greater than or equal to two percent of its previous value.
2.
An event object is created for the Frequency point if the frequency changes by 0.04 Hz or more from its previous value.
3.
An event object is created for these points if the current value of a point is in any way changed from its previous value.
4.
To support existing SCADA hardware that is not capable of 32-bit data reads, the upper and lower 16-bit portions of
these 32-bit values have been assigned to separate points. To read this data, it is necessary to read both the upper
and lower 16-bit portions, concatenate these two values to form a 32-bit value and interpret the result in the format
associated with the point as specified in Table 6–2: Data Formats on page 6–34.
5.
The data returned by a read of the User Map Value points is determined by the values programmed into the corre-
sponding User Map Address registers (which are only accessible via Modbus). Refer to Section 6.3.2: User-Definable
Memory Map Area on page 6–8 for more information. Changes in User Map Value points never generate event
objects. Note that it is possible to refer to a 32-bit quantity in a user map register, which may require the use of a 32-bit
variation to read the associated analog input point.
6.
The scale for pre-trip currents is determined by the value in point 9, which should not normally change
7.
The scale for currents is determined by the value in point 47, which should not normally change
8.
Each power quantity is available at two different points, with two different scale factors (kW and MW, for example). The
user should select the unit which is closest to providing the resolution and range desired. If 32-bit analog input capabil-
ity is present, the higher-resolution (kW, kvar, kVA) points should generally be used, since they provide the greatest
resolution.
9.
Analog input values may be –50000 to +50000 if so configured. Therefore, 32-bit analog input capability is required to
read the full possible range. If the SCADA equipment can only read 16-bit registers, the analog inputs should be con-
figured to operate within the range –32768 to +32767.
10. Each neutral voltage quantity is available at two different points, with two different scale factors (volts and tenths of a
volt). The user should select the unit which is closest to providing the resolution and range desired. If 32-bit analog
input capability is present, the higher-resolution (tenths of a volt) points should generally be used, since they provide
the greatest resolution.
250
F13
Positive kvarh
Class 2
251
F13
Negative kvarh
Class 2
252
F12
Generator Hours Online
Class 2
Table 6–8: ANALOG INPUTS POINT LIST (SHEET 4 OF 4)
INDEX
FORMAT
DESCRIPTION
EVENT CLASS
ASSIGNED TO
NOTES