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EXCEL 50/100/500/600/800 ATTRIBUTES
EN2B-0092GE51 R0512
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Pseudo totalizers: In the event that you have selected the datapoint type "pseudo totalizer inputs," you
must set the attribute "Scaling Factor" to "1"; otherwise, the number of pseudo
totalizer inputs will not be counted.
Sensor Offset
The attribute “Sensor Offset” is designed for the compensation of the resistance of
the sensor wiring for low-resistance sensors, like Pt 100, Pt 1000, Balco 500.
The voltage offset due to the wire resistance is approximately constant, the attribute
“Sensor Offset” functionality has therefore been designed to compensate constant
voltage offsets at the analog input.
Function principle The principle is that the attribute “Sensor Offset” can be defined at a selected tem-
perature, e.g., 1 °C at 20 °C. The Excel controller processes this temperature offset
into a voltage offset, e.g., -0.11 V, and applies this very voltage offset for correcting
(offsetting) all voltages measured.
In order to display a temperature, the controller processes the resulting voltage
back into a temperature. This principle and the processing (including mathematical
rounding) from “°C” into “volt” and back into “°C” leads to slightly inconstant offsets
across the temperature range.
Example for a selected “Sensor Offset” of 1°C:
Measured Temperature Corrected Temperature
20°C 19°C
-10°C -8,4°C
For XFL and XFC I/O modules, "Sensor Offset" functionality is supported from
CARE 5.0 and controller firmware 2.06.05 onwards.
CAUTION
Regarding sensor offset, the behavior of controllers with OS < 2.06.05
engineered using CARE 4 differs significantly from controllers with OS
2.06.05 and higher engineered using CARE 7 and higher.
For example, for XL50 internal AI and XL500 internal AI (XF521/527
modules), the sensor offset is subtracted from the datapoint value.
For XL50 and XL800 controllers using XF821 modules, the sensor offset is
added to the datapoint value.
See also section “Sensor Offset Handling” in Excel CARE – User Guide
(EN2B-0182GE51).
Suppress Point
The attribute "Suppress Point" means that datapoints are no longer processed and
checked. As a result, no alarms are generated for suppressed points. Where you
have flexible datapoints, this attribute acts upon all basic types of physical
datapoints.
IMPORTANT
Never suppress a datapoint used via your application program. This
causes system failure.
Switching Down
The attribute "Switching Down" is used in conjunction with flexible datapoints of the
type "feedback". On switching down from one stage to another, it determines