CHAPTER 5: SETTINGS TRANSDUCER INPUTS/OUTPUTS
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 5-425
5
5.10.3 DCmA outputs
SETTINGS TRANSDUCER I/O DCMA OUTPUTS DCMA OUTPUT H1(U8)
Hardware and software is provided to generate DCmA signals that allow interfacing with external equipment. Hardware
details are contained in chapter 3. The DCmA output channels are arranged in a manner similar to transducer input or CT
and VT channels. The user configures individual channels with the settings as follows.
The channels are arranged in sub-modules of two channels, numbered 1 through 8 from top to bottom. On power-up, the
relay automatically generates configuration settings for every channel, based on the order code, in the same manner used
for CTs and VTs. Each channel is assigned a slot letter followed by the row number, 1 through 8 inclusive, which is used as
the channel number.
Both the output range and a signal driving a given output are user-programmable via the following settings menu (an
example for channel M5 is shown).
The relay checks the driving signal (x in equations below) for the minimum and maximum limits, and subsequently re-
scales so the limits defined as
MIN VAL and MAX VAL match the output range of the hardware defined as RANGE. The
following equation is applied:
Eq. 5-49
where
x is a driving signal specified by the
SOURCE setting
I
min
and I
max
are defined by the RANGE setting
k is a scaling constant calculated as:
Eq. 5-50
The feature is intentionally inhibited if the MAX VAL and MIN VAL settings are entered incorrectly, for example when MAX VAL
–
MIN VAL < 0.1 pu. The resulting characteristic is illustrated in the following figure.
DCMA OUTPUT H1
DCMA OUTPUT H1
SOURCE: Off
Range: Off, any analog actual value parameter
DCMA OUTPUT H1
RANGE: –1 to 1 mA
Range: –1 to 1 mA, 0 to 1 mA, 4 to 20 mA
DCMA OUTPUT H1
MIN VAL: 0.000 pu
Range: –90.000 to 90.000 pu in steps of 0.001
DCMA OUTPUT H1
MAX VAL: 1.000 pu
Range: –90.000 to 90.000 pu in steps of 0.001
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