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MELSEC-Q
3   SPECIFICATIONS 
 
3.4.2 Details of buffer memory 
The following table indicates the functions and setting values of the buffer memory 
areas. 
 
Buffer memory address 
Item Details 
Initial 
value 
CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8
Sampling pulse 
number 
•  Stores the pulse number obtained by converting the input pulses 
into the unit pulse number using the pre-scale function. 
•  When the count enable signal (Y18 to Y1F) turns ON, count 
operation starts. The count range is 0 to 32767. 
•  The update timing is the interval set in the "count cycle setting 
value" of the 
buffer memory. 
(The initial value of the count cycle is 1s.) 
0 0 32 64 96 128 160 192 224
Comparison 
output selection 
•  Set whether the comparison output function is valid or invalid. 
•  If the setting value is other than 0 or 1, a comparison output 
setting range outside error (error code: 200) occurs. To clear the 
error, turn ON the error reset request (Y8 to YF) of the 
corresponding channel. After this, set a correct value and then 
turn ON the operating condition setting request flag (Y1). 
[Setting value] 
0: Comparison output function invalid 
1: Comparison output 
function valid 
0 1 33 65 97 129 161 193 225
•  Set the value to be compared with the "accumulating count 
value" of the buffer memory. 
•  If the setting value is outside the range, a comparison output 
setting range outside error (error code: 200) occurs. To clear the 
error, turn ON the error reset request (Y8 to YF) of the 
corresponding channel. After this, set a correct value and then 
turn ON the operating condition setting request flag (Y1). 
•  The relationships between the accumulating count value, 
comparison output setting value and accumulating counter 
comparison flag (X10 to X17) ON/OFF are as indicated below. 
 
Setting value and accumulating count 
value 
Accumulating counter 
comparison flag 
(X10 to X17) 
 
Setting value 
 accumulating count 
value 
OFF 
 
Setting value = accumulating count 
value 
ON 
 
Setting value 
 accumulating count 
value 
ON 
Comparison 
output setting 
value 
•  The accumulating counter comparison flag is cleared by turning 
ON the comparison signal reset request (Y10 to Y17) of the 
corresponding channel. 
•  When the accumulating counter is operating as a linear counter, 
the accumulating counter comparison flag that was turned OFF 
once does not turn ON until the accumulating count value 
reaches the comparison output setting value again after it has 
been reset. When the accumulating counter is operating as a 
ring counter, the flag turns ON when the accumulating count 
value reaches the comparison output setting value again in the 
ring processing. 
[Setting range: 0 to 99999999] 
0 
2 
3 
34 
35 
66 
67 
98 
99 
130 
131 
162
163
194
195
226
227
 
*: Refer to Section 9.3 for details of the error codes.