Advantech Data Acquisition Modules ADAM 4000, User Manual

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Data Formats and I/O Ranges
B-4 ADAM 4000 Series User’s Manual
The percentage is related to the full span of the configured range. For
instance, a nickel RTD is specified for -80
o
C to +100
o
C. Then, the
lower value of -80
o
C equals to 0% of span and the upper value of +100
o
C equals to 100% of span.
In the FSR mode, an over-range feature is automatically invoked by the
ADAM analog 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 values 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.
B.1.3 Twos complement hexadecimal
Twos Complement Hexadecimal format presents the data in ASCII
hexadecimal form providing a rapid communication, high resolution
and easy conversion to computer-compatible integer format.
In order to indicate twos complement hexadecimal, bits 0 and 1 of the
data format/checksum/integration time parameter must be set to 10.
This format displays data in the form of a 4-character hexadecimal
string.
This string represents a 16-bit twos complement binary value. Positive
full scale is denoted as 7FFF (+32,767) while negative full scale is
represented by the value 8000 (-32,768). The resolution is digit one at
the least significant bit (LSB) of 16 bits.
Example
The input value is -1.234 V. An analog input module is configured for a
±5 V range. The value returned is: E069 (cr)
This value is equivalent to the signed integer -8087.
Input ranges with voltage and milliamp values are used with the full
calibrated voltage range from 8000 to 7FFF. For instance, an ADAM-
4011 module is given a ±5 V input range. In this case, -5 V is
represented as 8000h and +5 V is denoted as 7FFFh.
When thermocouple input ranges are used, an input range which is
bipolar and symmetric at zero is assumed. The following table provides
several examples.