E-Bus Analog I/O Data Representation

The limit with the largest value is used as the Full Scale Value for current and voltage measurement in analog I/O devices. It is represented by the decimal value +32767 (hex: 0x7FFF).

The bit resolution shown in the product Description (see following image) states the resolution of the digital-to-analog and analog-to-digital converters used in the product, not the data range of the values. This means that the device may not be able to differentiate between two values, i.e. the analog output behavior will be identical for two different user or application-specified values such as 0 and 3; the analog devices will output 0V for both 0 and 3.

For example, the AKT2G-AT-410 is a 0-10V device with 12-bit resolution. The digital converted data output from this device is a 15-bit resolution (with signed data representation), which results in a loss of 3-bits representation. If you feed a signal voltage of 0.00122 V (which is read as 4 digitally) then output reading will show this value as 0V.

Analog input thermocouple devices represent 0°C as a data value of 0. Each increment of the data value represents a 0.1°C increment in measured temperature. This means the widest data range of values for the thermocouple devices is from decimal values -2000 to +13700, representing -200°C and +1370°C respectively.

Analog Output Signal Table

Value Output Signal
Decimal Hexadecimal AKT2G-AT-410, AKT2G-AT--810 AKT2G-AT-425
32767 0x7FFF 10V 10V
16383 0x3FFF 5V 5V
16 0x0010 0.00488V 0.00488V
8 0x0008 0.00244V 0.00244V
1 0x0001 0V (limited by 12-bit resolution on DAC) ...
0   0V 0V
-1 0xFFFF out-of-range ...
-8 0xFFF8   0V (limited by 12-bit resolution on DAC)
-16 0xFFF0 ... -0.00488V
-16838 0xC001   -5V
-32768 0x8000 out-of-range -10V

Analog Input Signal Table

Input Signal Value
AKT2G-AN-200,
AKT2G-AN-400,
AKT2G-AN-440
AKT2G-AN-240
(temperature mode)
AKT2G-AN-430 Decimal Hexadecimal
out-of-range out-of-range 10V or 20mA 32767 0x7FFF
out-of-range out-of-range 5V or 10mA 16383 0x3FFF
1370.0°C 1370.0°C ... 13700 0x3584
0.1°C 0.1°C 0.0003V or 0.0006mA 1 0x0001
0°C 0°C 0V or 0mA 0  
-0.1°C -0.1°C -0.0003V or -0.0006mA -1 0xFFFF
-200.0°C -200.0°C ... -2000 0xF830
out-of-range out-of-range -5V or -10mA -16838 0xC001
out-of-range out-of-range -10V or -20mA -32768 0x8000