GE Multilin 745 Communications Manual page 110

DNP PROTOCOL
3–8
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 these points if the current value of a point is in any way
changed from its previous value.
3. An event object is created for the system frequency point if the system frequency
changes by 0.04 Hz or more from its previous value.
4. The data returned by a read of the user map value points is determined by the values
programmed into the corresponding user map address registers (which are only
accessible via Modbus). Refer to Accessing data via the user map on page 2–9 for more
information. Changes in user map value points never generate event objects. Because
of the programmable nature of the user map, it cannot be determined at read time if
the source value is signed or unsigned. For this reason, the data returned in a 32-bit
variation is never sign-extended even if the source value is negative.
5. Depending upon the configuration and/or programming of the 745, this value may
not be available. Should this be the case, a value of zero will be returned.
6. Points with format F78 and F93 are scaled based upon the value of the
setpoint (point 0). It is necessary to read point 0 and refer to the
PHASE CT PRIMARY
descriptions of these formats (see Memory map data formats on page 2–69) to
determine the scale factor.
7. As for Note 6, except the affected formats are F79 and F94 and the scaling is
determined by the value from Point 1.
1. As for Note 6 except the affected formats are F80 and F95 and the scaling is
determined by the value from Point 2.
2. As for Note 6 except the affected format is F81 and the scaling is determined by the
value read from Point 3.
3. As for Note 6 except the affected format is F82 and the scaling is determined by the
value read from Point 4.
4. As for Note 6 except the affected format is F83 and the scaling is determined by the
value read from Point 5.
5. The total accumulated loss of life is a 32-bit, unsigned, positive value. As a
consequence, a master performing 16-bit reads cannot be guaranteed to be able to
read this point under all conditions. When this point's value exceeds 65535 (FFFFh), a
16-bit read will return FFFFh and the over-range bit in the flag returned with the data
will be set. Because of this possibility of over-range, the default variation for this
object is 2 (that is, 16-bit analog input with flag).
6. There are two defined maps for analog output points. The map used is specified by
the setting of the "point mapping" setpoint at Modbus address 10D1h. This setpoint
may be set to a value of "Disabled" or "Enabled". When "Disabled", only the
preassigned analog output points are available at indices 0 through 72.
When "Enabled", the user map values are assigned to points 0 through 119 with the
preassigned analog outputs following beginning with point index 120. The value read from
points 0 through 119 will depend upon the value programmed into the corresponding user
map address setpoint (programming these setpoints can only be accomplished via
Modbus). Refer to Accessing data via the user map on page 2–9 for more information.
Please note that changes in user map values never generate event objects.
745 TRANSFORMER PROTECTION SYSTEM – COMMUNICATIONS GUIDE
CHAPTER 3: DNP PROTOCOL
WINDING 1