Rtd/Ma Input/Ma Output Connection - ABB RELION REX640 Technical Manual

1MRS759142 C
3.15.5
REX640
Technical Manual
Slot# – mA1
AO_VAL AI_VAL
HIGH_ALARM
HIGH_WARN
LOW_WARN
LOW_ALARM
Slot# – RTD 7
AI_VAL
HIGH_ALARM
HIGH_WARN
LOW_WARN
LOW_ALARM
SENSOR_FLT
GUID-E6B59AA5-B76A-43B8-92C2-B067DFD43422 V1 EN
Figure 62: Application example for RTD input to mA output
Output [mA]
Value maximum 20
Value knee point 4 19
Value knee point 3 12
Value knee point 2 11
Value knee point 1 5
Value minimum 4
10
GUID-A7FD8A86-149E-4BE3-848D-9CF2615D3A8A V1 EN
Figure 63: Scaling of AO_VAL to mA output with four knee points
Incorrect knee point values against the minimum and maximum
values and a too narrow interval between the knee point values can
cause inaccuracy to the output scaling function. Use increasing
linearity and a value interval >1.0 for most accurate results.

RTD/mA input/mA output connection

RTD inputs can be used with a 2-wire or 3-wire connection with common ground.
When using the 3-wire connection, it is important that all three wires connecting the
40 70 100
Section 3
Basic functions
AO_VAL
130 160
169