Scaling Dnp Analog Values - ABB REF610 Technical Reference Manual

1MRS755535
Feeder Protection Relay
Technical Reference Manual - ANSI Version
relay first waits until the link becomes idle. After this, a backoff time starts. When
the backoff time elapses, the relay checks the link again. If the link is not busy, the
relay starts the transmission. The backoff time is calculated as follows:
backoff time = silent interval + random delay
The silent interval is set with SPA parameter 503V232 and the maximum random
delay with SPA parameters 503V233 (the width of a single time slot in
milliseconds) and 503V234 (the maximum number of time slots). By setting the
time-slot width to 10 milliseconds and the maximum number of time slots to 10, for
instance, the maximum random delay is 100 milliseconds.
In a network consisting of several slaves, the priority between the
devices are defined with SPA parameters 503V233 and 503V234. A
device with shorter silent interval and maximum random delay has
higher sending priority than a device with longer silent interval and
maximum random delay.
Collision detection is always active during transmission (provided that it has been
enabled). While sending a message, the relay supervises collisions on the link. If a
collision is detected, the transmission is immediately cancelled. After this, the relay
tries to transmit the message again, using collision avoidance before sending the
message.

Scaling DNP analog values

The DNP analog values can be scaled using either an internal (fixed) or a user-
defined scaling factor. If the scaling factor index for a certain analog value is set to
0, the internal scaling factor is used. If set to 1...5, the user-defined scaling factor of
the corresponding scaling factor parameter, SPA parameter 503V (100+index), is
used:
Scaling factor 1
503V101
Scaling factor 2
503V102
Scaling factor 3
503V103
Scaling factor 4
503V104
Scaling factor 5
503V105
Example:
Phase current l
a
Internal scaling factor
Default DNP range
0.00...50.0 × I (CT)
n
100
0...5000
REF610 REF610
115