GE C70 Instruction Manual page 392

TRANSDUCER INPUTS/OUTPUTS
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
following equation is applied:
where
x is a driving signal specified by the
I and I are defined by the
min max
k is a scaling constant calculated as:
5
The feature is intentionally inhibited if the
– < 0.1 pu. The resulting characteristic is illustrated in the following figure.
MIN VAL
Settings
DCMA OUTPUT F1 SOURCE
(FlexAnalog parameters) such as power, current amplitude, voltage amplitude, power factor, etc. can be configured as
sources driving DCmA outputs. See Appendix A for a list of FlexAnalog parameters.
DCMA OUTPUT F1 RANGE
to work with different ranges. The three most commonly used output ranges are available.
DCMA OUTPUT F1 MIN VAL
used to control the mapping between an internal analog value and the output current. The setting is entered in per-unit
values. The base units are defined in the same manner as the FlexElement base units.
5-268
and match the output range of the hardware defined as
MIN VAL MAX VAL
I if x

min

I if x
I =

max
out

k x (
MIN VAL

–
setting
SOURCE
setting
RANGE
k = ------------------------------------------- -
MAX VAL
and
MAX VAL
Figure 5-144: DCmA output characteristic
I
max
I
min
MIN VAL
— This setting specifies an internal analog value to drive the analog output. Actual values
— This setting allows selection of the output range. Each DCmA channel can be set independently
— This setting allows setting the minimum limit for the signal that drives the output. This setting is
C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL
<
MIN VAL
>
MAX VAL
) I + otherwise
min
I I
–
max min
MIN VAL
–
settings are entered incorrectly, for example when
MIN VAL
DRIVING SIGNAL
MAX VAL
CHAPTER 5: SETTINGS
. The
RANGE
MAX VAL
842739A1.CDR
Eq. 5-26
Eq. 5-27