Advantech Adam - 4021, User Manual, Page: 236 / 286

ADAM-4000 Series User Manual 224
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 sym
-
metric at zero is assumed. The following table provides several examples.
The given span of the specified range is used to determine the RTD input ranges for
twos complement hexadecimal values. For an example, if the nickel RTD is specified
for the range -80°C to +100°C, the corresponding values in hexadecimal notation
would be 8000h to 7FFFh.
Thermocouple Type Temperature Range (Degrees) Temperature Range (Hex)
J 0° C to 760° C 0000h - 7FFFh
T -100° C to 400° C E000h - 7FFFh
R 500° C to 1750° C 2492h - 7FFFh