Conversion Method - Mitsubishi Electric MELSEC iQ-F FX5 User Manual

Conversion method

This function sets the A/D conversion or temperature conversion method for each channel.
The conversion speed is 1 ms when the input range is current and voltage, 40 ms in the case of resistance temperature
detector and thermocouple.
A/D conversion or temperature conversion is performed asynchronously. The A/D conversion or temperature conversion
sampling cycle varies according to the number of channels respectively set.
The conversion process order and sampling cycle for when CH1 is set to the temperature input range, and CH2, CH4, and
CH5 are set to the A/D input range are shown below.
Conversion processing of
temperature input range of
module
Conversion processing of
A/D input range of module
Sampling processing
The analog input value and temperature input value are converted for each sampling period and stored as digital output value
and digital operation value.
• When input range is set only with current, voltage, or resistance temperature detector, and thermocouple only, perform
conversion for each channel.
• When setting the current, voltage, resistance temperature detector, and thermocouple in the input range, convert
asynchronously in each sampling period.
A/D conversion and temperature conversion are performed asynchronously, so the respective sampling
cycles are as shown below.
• The A/D conversion sampling cycle is "conversion speed (1 ms)  number of A/D conversion enabled
channels".
• The temperature conversion sampling cycle is "conversion speed (40 ms)  number of temperature
conversion enabled channels".
Whether to enable or disable the conversion can be set for each channel. Disabling the conversion on unused
channels reduces the sampling cycle.
For example, when setting the temperature conversion to 2 channels (CH1, CH4) conversion enabled, the
conversion period is 80 ms (40 ms  2).
Sampling cycle of temperature conversion
(40 ms × 1 = 40 ms)
Conversion speed (40 ms)
CH1 conversion processing
Sampling cycle of A/D conversion
(1 ms × 3 = 3 ms)
Conversion Conversion Conversion
speed speed speed
(1 ms) (1 ms) (1 ms)
CH2 CH4 CH5
conversion conversion conversion
processing processing processing
Conversion Conversion Conversion
speed speed
(1 ms) (1 ms) (1 ms)
CH2 CH4
conversion conversion conversion
processing processing processing
speed
CH4
3 FX5-8AD
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3.4 Functions
3