The RTD inputs have separate setting values for value update interval. The settings
are: "No delay", "10 ms delay", "50 ms delay" and "100 ms delay". Between the update
intervals the RTD input constantly returns the last valid value before updating to the
new value after the interval time expires.
3.15.3.1 Input mode
Table 100: Analog input modes for the mA inputs
Input mode Description
Not in use Default selection when the corresponding input is not used.
–20...20 mA The analog input covers the range of –20...20 mA. The input
can be used in a narrower range by setting
Input minimum
and
Input maximum
. Settings
Value minimum
and
Value
maximum
are used to scale the output within the appropri-
ate range. The output unit is selected with the set
Value unit
.
Table 101: Analog input modes for the RTD inputs
Input mode Description
Not in use Default selection when the corresponding input is not used.
Resistance Freely settable resistance input.
Input minimum
and
Input
maximum
define the resistive input range. The correspond-
ing output can be scaled based on
Value minimum
and
Value
maximum
. The output unit is selected with the set
Value
unit
.
Pt 100 The input is expected to be the selected temperature sensor.
The set
Value unit
should be set to degrees Celsius. The
expected input range is –40...200°C. However, the output can
be scaled to a narrower output range by setting
Value mini-
mum
and
Value maximum
.
Pt 250
Ni 100
Ni 120
Ni 250
Selection of value unit format
Each input has an independent
Value unit
setting that is used to select the unit
for the channel value representation. The default value for the
Value unit
setting is
"Dimensionless". The
Input minimum
,
Input maximum
,
Value maximum
and
Value
minimum
settings have to be adjusted according to the input channel and if
Value
unit
is changed.
When the RTD channel input is used for the temperature sensor type, the
Value
unit
setting needs to be changed to "Degrees Celsius". When
Value unit
is set to
"Degrees Celsius", linear scaling is not applied but the default range (–40…200°C)
can be decreased with the
Value maximum
and
Value minimum
settings.
When the DC milliampere signal is connected to the mA channel and the application
requires a linear scaling of the input range, the
Value unit
setting value has to be set
to "Dimensionless" so that the input range can be linearly scaled with the settings
Input minimum and Input maximum to
Value minimum
and
Value maximum
. When
milliampere is used as a value unit,
Value unit
has to be "Ampere". When
Value unit
is set to "Ampere", the default range (–20…20 mA) can be decreased with the
Value
maximum
and
Value minimum
settings.
1MRS759142 F
Basic functions
REX640
Technical Manual
171
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