Mitsubishi Electric R60AD8-G - Page 25

1 FUNCTIONS
1.4 A/D Conversion Method
23
1
When the number of processing times is less than 4 due to the set time, a time average setting range error
(error code: 192H) occurs. The value 0 is stored in the following buffer memory areas.
• 'CH1 Digital output value' (Un\G400)
• 'CH1 Digital operation value' (Un\G402)
• 'CH1 Digital output value (32 bits)' (Un\G410, Un\G411)
■Count average
The A/D converter module executes the A/D conversion for a set number of times, and performs the averaging processing on
the total value excluding the maximum and the minimum values. The processed values are stored in the buffer memory area.
The time taken for the mean value calculated through the average processing to be stored in the buffer memory changes
depending on the number of channels where the A/D conversion is enabled.
Processing time = Set number of times  (Number of conversion enabled channels  Conversion speed)
Ex.
The following table shows the processing time with the setting below.
5 (times)  (4 (CH)  10 (ms)) = 200 (ms)
A mean value is output every 200ms.
Because the count average requires a sum of at least two counts excluding the maximum and minimum
values, the set number of times should be four or more.
■Moving average
The A/D converter module averages digital output values taken at every sampling period for a specified number of times, and
stores the mean value in the buffer memory area. Since the averaging processing is performed on a moving set of sampling,
the latest digital output values can be obtained.
The following figure shows the moving average processing of when the set number of times is five.
Item Setting
Number of channels where the A/D conversion is enabled Four channels (CH1 to CH4)
Set number of times Five times
(1) + (2) + (3) + (4)+ (5)
5
(2) + (3) + (4) + (5)+ (6)
5
(3) + (4) + (5) + (6)+ (7)
5
32000
(1)
(2)
(3) (4)
(5)
(6)
(7)
(8) (9)
(10) (11)
(12)
16000
0
0
(a) (b) (c)
ON
OFF
1st storage (a) 2nd storage (b) 3rd storage (c)
Data transition in buffer memory
0
3rd storage (c)
Time [ms]
2nd storage (b)
1st storage (a)
Sampling cycle
Digital output value
'CH1 Digital output value'
(Un\G400)
'A/D conversion
completed flag' (XE)