Advantech Adam - 4021, User Manual, Page: 235 / 286

223 ADAM-4000 Series User Manual
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B.1.2 Percent of FSR
This mode is used by setting bits 0 and 1 of the data format/checksum /integration
time parameter to 01. The format used in Percent of FSR consists of a plus (+) or
minus (-) sign followed by five decimal digits including a decimal point. The maximum
possible resolution is 0.01% with the decimal point fixed.
Data are given as the ratio of the input signal to the full-scale range.
Example 1
The input value is +2.0 V. The input module is configured for a range of ±5 V. The
response to the Analog Data In command is as follows: +040.00 (cr)
The full calibrated voltage range ranges from -100% to 100% as voltage input ranges
are always bipolar. A ±5 V input would range from -5 V (-100%) to 5 V (100%).
In this example the input is represented by +40% of the full-scale range which equals
to (+(40/100) x 5 V = +2.0 V) the actual input value.
Example 2
The input value is 652.5o C, and a type E thermocouple (0°C to 1000°C) is config
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ured in the analog input module. The response to the Analog Data In command is:
+065.25 (cr)
The result shows that the value of the input (652.5°C) is 65.25% of the full-scale
range (1000°C).
Thermocouple input ranges are always assumed to be bipolar with zero being the
point of symmetry. This holds true regardless of the specified range of operation. For
example, when we use a type J thermocouple (0°C to 760°C), 760°C corresponds to
+100% and 0°C corresponds to 0%. Even if 0°C lies outside of the specified opera -
tion range for the thermocouple, zero will remain as the point of symmetry. For
instance, a type B thermocouple is specified for operation from +500°C to +1800°C.
In this case +1800°C corresponds to + 100% and 500°C corresponds to +27.77%.
The percentage is related to the full span of the configured range. For instance, a
nickel RTD is specified for -80°C to +100°C. Then, the lower value of -80°C equals to
0% of span and the upper value of +100°C equals to 100% of span.
In the FSR mode, an over-range feature is automatically invoked by the ADAM ana
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log input modules if the value exceeds the uppermost value of the input range. For
instance, an analog module which is configured for a ±5 V range has one of the val -
ues r 5.5V. The resulting value would then be 110%.
The readings must fall within the input range for accuracy assurance. Although they
are typically linear readings, anything which falls between ±100% and ±115% limits
may not be accurate. Furthermore, readings beyond these limits are neither accurate
nor linear.