422
Analog I/O Units Section 7-4
0 to 20 mA
The hexadecimal values 0000 to 1770 (0 to 6000) correspond to an analog
current range of 0 to 20 mA. The entire output range is 0 to 21 mA.
4 to 20 mA
The hexadecimal values 0000 to 1770 (0 to 6000) correspond to an analog
current range of 4 to 20 mA. The entire output range is 3.2 to 20.8 mA.
Averaging Function for
Analog Inputs
The averaging function can be enabled for inputs using the DIP switch. The
averaging function stores the average (a moving average) of the last eight
input values as the converted value. Use this function to smooth inputs that
vary at a short interval.
Open-circuit Detection
Function for Analog
Inputs
The open-circuit detection function is activated when the input range is set to
1 to 5 V and the voltage drops below 0.8 V, or when the input range is set to 4
to 20 mA and the current drops below 3.2 mA. When the open-circuit detec-
tion function is activated, the converted data will be set to 8,000.
The time for enabling or clearing the open-circuit detection function is the
same as the time for converting the data. If the input returns to the convertible
range, the open-circuit detection is cleared automatically and the output
returns to the normal range.
0 mA
20 mA
21 mA
0000 (0)
189C
(6300)
1770
(6000)
7FFF
8000
Conversion Data
Hexadecimal (Decimal)
4 mA
20 mA
20.8 mA
3.2 mA
189C
(6300)
1770
(6000)
0 mA
7FFF
FED4
(−300)
8000
Conversion Data
Hexadecimal (Decimal)