FEATURE INFORMATION
6-30
Range is up to 65 000 kVAR (65 MVAR).
Accuracy is ±2% of displayed.
Resolution display is 1 kVAR.
Signed Real and Reactive Power Readings
If the 565/575 is communicating with a revision E MTM or
MTM Plus, the kW and kvar readings sent to the 565/575 will
also include the polarity sign. The 565/575 will display this
information as shown below.
REAL POWER
+VE 65 000 kW
REACTIVE POWER
+VE 65 000 kW
To interpret the real power readings at Modbus register 70h
and the reactive power readings at Modbus register 71h, one
must first read register 6Dh. This latter register indicates the
sign of the real and reactive power readings. Refer to the
565/575 DATA MAP for an explanation of the data format for
register 60h. With knowledge of the real and reactive power
signs, the formatting of the Power Data at register 70h and
71h is indicated in the 565/575 Data Map.
Generally, if the sign at data register 6Dh is zero, the corre-
sponding data can be read directly. If the sign data at register
6Dh is not zero, a 2’s complement operation should be
performed on the data first.
MWhrs
This is real power used. This value is supplied by the MTM
and is for metering purposes only. There are no alarm or trip
functions.
Range is up to 65 000 MWhrs.
Accuracy is ±2% of displayed.
Resolution displayed is 1 MWhr.
kW Demand
This measures average real power demanded over time. The
kW value is supplied by the MTM while the demand value is
averaged by the 565.
Setpoints:
Time period 5-120 min, in steps of 1 min. Default value 5
minutes.
Alarm level 100 - 65 000 kW in steps of 100 kW. Default
value 1 000 kW.
Alarm relay AUX 1, 2, and AUX 1&2. Default AUX 1.
kVAR Demand
This measures average reactive power demanded over time.
This value is supplied by the MTM but averaged by the 565.
Setpoints:
Time period 5-120 min, in steps of 1 min. Default value 5
minutes.
Alarm level 100 - 65 000 kVAR in steps of 100 kVAR.
Default value 1 000 kVAR.
Alarm relay AUX 1, 2, and AUX 1&2. Default AUX 1.
The 565/575 contains a line which allows the clearing of the
MWhrs data calculated by the MTM/MTM Plus. This setpoint
can be found in the Actual Values Metering Data page and
appears as below:
CLEAR ENERGY
USED DATA? NO
This MTM/MTM Plus parameter can also be cleared with the
Modbus “Force Single Coil” function code 05h and operation
code 15h.
Retrieval of Event Records via Serial Communication
To facilitate the retrieval of event records, a register called the
Start of Event Queue is implemented at memory location
19h. The low order byte of this register gives the record
number of the most recent event (0 to 27h). The high order
byte is a free running wraparound counter incremented
every 40 events. The Start of Event Queue register will be
reset to zero if the event recorder is cleared.
For the first 40 events, the Start of Event Queue register will
read 00h. In this case, the record number of the most recent
event will correspond to the Number of Events found at
register 74h. With more than 40 events, the record number of
the most recent event will be the lower order byte of the Start
of Event Queue register. A reading of 00h in this lower order
byte coincides with event record 28h.
The event record number points to the following memory
map addresses:
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