Measurement Chain Supervision; Self-Supervision - ABB RELION Series Technical Manual

1MRS758755 A
3.12.2.4
3.12.2.5
REC615 and RER615
Technical Manual
The input scaling can be bypassed by selecting Value unit = "Ohm"
when Input mode = "Resistance" is used and by selecting Value unit =
"Ampere" when Input mode = "0...20 mA" is used.
Example for linear scaling
Milliampere input is used as tap changer position information. The sensor information
is from 4 mA to 20 mA that is equivalent to the tap changer position from -36 to 36,
respectively.
X130-Input#
20 mA
Input maximum
"0..20mA"
Input mode
4 mA
Input minimum
-36
Value minimum
GUID-85338A5E-3D2F-4031-A598-EA8A525190D3 V1 EN
Figure 33: Milliampere input scaled to tap changer position information

Measurement chain supervision

Each input contains a functionality to monitor the input measurement chain. The
circuitry monitors the RTD channels continuously and reports a circuitry break of any
enabled input channel. If the measured input value is outside the limits, minimum/
maximum value is shown in the corresponding output. The quality of the
corresponding output is set accordingly to indicate misbehavior in the RTD/mA input.
Table 36: Function identification, limits for the RTD/mA inputs
Input
RTD temperature, high
RTD temperature, low
mA current, high
Resistance, high

Self-supervision

Each input sample is validated before it is fed into the filter algorithm. The samples are
validated by measuring an internally set reference current immediately after the inputs
"Dimensionless"
Value unit
Limit value
> 200 °C
< -40 °C
> 23 mA
> 2000 Ω
Section 3
Basic functions
AI_VAL#
36
Value maximum
89