Confirming The Current Value - Mitsubishi Q Series User Manual

9 POSITIONING CONTROL

9.1.4 Confirming the current value

Current feed value
Current feed value
Md.1
Example
Program in which the axis 1 current feed value is read to D104 and D105
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Values showing the current value
The following address is used as value to show the position in the QD70.
This address (current feed value) is stored in the monitor data area, is used in
monitoring the current value display, etc.
• This is the value stored in " Md. 1 Current feed value".
• This value has an address established with a "machine OPR control" as a
reference, but the address can be changed by changing the current value
to a new value.
• Update timing
QD70P4: 1ms
V
OP
0 1
Fig. 9.7 Current feed value
Restrictions
1) If the "current feed value" stored is used for control, an error of 1ms (for the
QD70P4) or 2ms (for the QD70P8) is produced at the update timing of the
current value.
2) The "current feed value" is controlled by a signed numerical value.
(Range: -2147483648 to 2147483647 pulse) Hence, continuation of counting
up will cause an overflow and continuation of counting down will cause an
underflow. Normal operation cannot be performed in an overflow or
underflow status. If there is a possibility of an overflow or underflow, set the
software stroke limit function valid. (Refer to "Section 11.4 Software stroke
limit function" for details.)
Monitoring the current value
The "current feed value" is stored in the following buffer memory address, and can
be read using a "DFRO (P) command" from the PLC CPU.
Md. 1 Current feed value
QD70P8: 2ms
to 10000 20000
Buffer memory addresses
Axis 1 Axis 2 Axis 3 Axis 4 Axis 5 Axis 6 Axis 7 Axis 8
70 170 270
71 171 271
MELSEC-Q
Current value is changed to 20000
by current value changing.
t
Address after current value
changing is stored.
370 470 570 670
371 471 571 671
<Read current feed value to D104 and D105>
770
771
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