4: A
NALOG
I/O C
ONTROL
4-13
Analog Input Minimum/Maximum Values
For analog input values, when Optional range is selected for the Data Type, designate the analog input data minimum and
maximum values which can be –32,768 through 32,767.
In addition, when using resistance thermometers (Pt100, Pt1000, Ni100, or Ni1000) with the Celsius or Fahrenheit Data
Type and the
×
100 scale, select the analog input data minimum value from 0 or another value in the pull-down list. The
maximum value is changed automatically according to the selected minimum value.
Filter Value
The filter function is available for the ladder input type FC4A-J4CN1, FC4A-J8C1, and FC4A-J8AT1 only. Filtering
ensures smooth input of analog data into the CPU module. For the filtering function of analog input signals, see page 4-4.
Valid values are 0 through 255.
Thermistor Parameter
Thermistor parameters are enabled when selecting NTC thermistor for the analog input type of the FC4A-J8AT1. The
same parameters are specified for four channels: CH0 to CH3 and CH4 to CH7.
For NTC type thermistors, analog input data can be calculated from the following formula:
For PTC type thermistors, linearize the analog input data using the XYFS instruction.
Analog Input Data
The analog input signal is converted into a digital value within the range specified by the analog input data type and appli-
cable parameters, and is stored to a data register allocated to analog input data. The analog input data register number is
shown under Data in the Configure Parameters dialog box.
END Refresh Type
The analog input signal is converted into a digital value and stored to a data register, such as D760 or D766, allocated to
analog input channel 1 or 2 on analog module number 1 through 7 depending on the mounting position.
The analog input data stored in the allocated data register is updated whether the CPU module is running or stopped. When
the CPU module is running, the update occurs at the END processing of every scan or 10 ms, whichever is longer. When
the CPU module is stopped, the update occurs every 10 ms.
Ladder Refresh Type
The analog input signal is converted into a digital value and stored to a data register determined by the data register num-
ber selected in the Configure Parameters dialog box of the ANST macro. The analog input data stored in the allocated data
register is updated when the RUNA instruction contained in the ANST macro is executed.
When a certain channel of a ladder refresh type analog input module is not used, data registers allocated to the unused
channel will store indefinite values if the values are read out of the analog input module. Do not use the allocated data reg-
isters for other purposes.
Only when the analog input status code is 0, the analog input data is assured. Make sure that a user program reads analog
input data only when the analog input status code is 0.
Analog Input Operating Status
The operating status of each analog input channel is stored to a data register allocated to analog input operating status.
While the analog input is operating normally, the data register stores 0. The analog input operating status data register
number is shown under Status in the Configure Parameters dialog box.
Channel
NTC Thermistor Parameters
(Values indicated on the thermistor)
Valid Range
CH0 to CH3
CH4 to CH7
R0:
Thermistor resistance value at the temperature (°C)
0 to 65535
T0:
Temperature (°C)
–32768 to 32767
B:
Thermistor B parameter (Kelvin)
0 to 65535
Analog Input Data
B
T0
×
B
T0
r R0
⁄
(
)
log
×
+
-------------------------------------------------
=
where, r = thermistor resistance (
Ω
)
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