Count Value Reading - Mitsubishi QD60P8-G User Manual

5 DETAILS AND SETTING OF FUNCTIONS

5.1.3 Count value reading

Item
Sampling pulse number
Accumulating count value
Input pulse value
Item
Counter reset request
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This section explains how to read the count values (sampling pulse number,
accumulating count value, input pulse value) stored in the buffer memory.
The accumulating count value and input pulse value are stored in the buffer memory
as two words (32 bits). When reading the count value from the module, always read
two words together.
The buffer memory addresses where the count values are stored are as follows.
CH1 CH2
0 32
8 40
9 41
10 42
11 43
The buffer memory addresses of the counter reset requests for resetting the count
values are as follows.
CH1 CH2
13 45
The update timings of the count values are as follows.
Item
Sampling pulse number
Accumulating count value
Input pulse value
POINT
When reading the accumulating count value or input pulse value, always read two
words together.
If it is read in single word unit, a wrong count value may be read due to a data
mismatch between the lower word and upper word when the count value is
updated halfway during read.
[Program example]
[Incorrect program example]
Buffer memory address
CH3 CH4 CH5
64 96 128
72 104 136
73 105 137
74 106 138
75 107 139
Buffer memory address
CH3 CH4 CH5
77 109 141
Count cycle setting value (Refer to Section 5.1.4)
MELSEC-Q
CH6 CH7
160 192
168 200
169 201
170 202
171 203
CH6 CH7
173 205
Update timing
10ms
CH8
224
232
233
234
235
CH8
237
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