MITSUBISHI ELECTRIC Mitsubishi Programmable Logic Controller QD75D - Manual (Page 531)

12 - 55
MELSEC-Q
12 CONTROL SUB FUNCTIONS
[Calculation of positioning address and concept of absolute position
detection system]
Use the following expression to calculate the positioning address.
(Positioning address) = (movement amount per pulse) (number of output pulses)
+ (OP address).............................................. Expression 1
1. Concept for the unit of mm, inch or pulse
The range which satisfies Conditions 1 and 2 can be used as the positioning
address of the absolute position detection system.
The range which does not satisfy Conditions 1 and 2 cannot be used as the
positioning address of the absolute position detection system.
The concepts of the positioning addresses in mm, inch and pulse are identical,
the following examples provide those of the mm unit.
Example 1.
(1) There are the following conditions to calculate the positioning address:
• Movement amount per pulse: 0.1 (
µ
m)
•
OP address: 0.0 (
µ
m)
• Feedback pulses = 8192 (pulse)
(2) Calculate the upper and lower limit values of the positioning address which
can be specified from the output pulse count using range in Condition 1 and
the positioning address calculation expression (Expression 1).
• Lower limit value of positioning address (the number of negative pulses in
Condition 1 is used for calculation)
(Positioning address) = (Movement amount per pulse)
(number of output pulses) + (OP address)
=0.1 (-268435456) + 0.0
=-26843545.5 (
µ
m)
• Upper limit value of positioning address (the number of positive pulses in
Condition 1 is used for calculation)
(Positioning address) = (Movement amount per pulse)
(number of output pulses) + (OP address)
=0.1 (-268435456) + 0.0
=-26843545.5 (
µ
m)
(3) The upper and lower limit values of the positioning address calculated are
within the range of Condition 2.
Hence, the positioning range [-26843545.6 (
µ
m) to 26843545.5 (
µ
m)]
calculated in Condition 1 can be used in the absolute position detection system.
Positioning outside of the range -26843545.6 (
µ
m) to 26843545.5 (
µ
m)
cannot be used in the absolute position detection system.
Unit:
µ
m
OP
0 -214748364.8 214748364.7 -26843545.6 26843545.5
Unusable range in
absolute position
detection system Unusable range in
absolute position
detection system
Usable range in absolute
position detection system