Nova Electronics MCX514, Руководство пользователя

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NOVA electronics Inc. MCX514 -
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－ 16 －
2.1.2 Absolute Position Driving
Absolute position driving performs the driving by setting the destination point based on a home (logical position counter = 0). The
destination point can be set by absolute coordinates regardless of the current position. The IC calculates drive direction and output
pulse number according to the difference between the specified destination point and current position, and then performs the
driving. In absolute position driving, the destination point should be set by absolute coordinates within the range of driving space.
So, the user first needs to perform automatic home search to determine the logical position counter before driving.
0 +10,000 +20,000
[Absolute coordinates]
-20,000 -10,000
TP ： +20,000 TP ： -20,000
(Home)
Current position
Fig. 2.1-3 Example of Specifying Finish Point (TP) in Absolute Position Driving
Absolute position driving performs constant speed driving or acceleration / deceleration driving as well as relative position
driving.
Command code for absolute position driving is 54h. To perform absolute position driving in linear acceleration / deceleration, the
following parameters must be set.
Table 2.1-2 Setting Parameters
：
Absolute Position Driving
Parameter Symbol Comment
Acceleration / Deceleration AC
／
DC
No need to set deceleration when acceleration and
deceleration are equal
Initial speed SV
Drive speed DV
Drive pulse number /
Finish point
TP Set the destination point by absolute coordinates.
2.1.3
Counter Relative Position Driving
Counter relative position driving performs the driving by setting the direction and drive pulse number to the destination point
based on the current position. Unlike relative position driving, driving is performed in a direction opposite to the sign of the pulse
number that is set in drive pulse number (TP). This is useful for when the user wants to determine a drive direction using a driving
command, by setting the predetermined positive value to the drive pulse number in advance.
If the negative value is set to the drive pulse number, counter relative position driving performs the driving in the
＋
direction.
Counter relative position
driving command (51h)
Relative position
driving command (50h)
Drive pulse number(TP)=20,000
To the
－
direction
20,000 pulses
To the
＋
direction
20,000 pulses
＋
direction
－
direction
Current position
Fig. 2.1-4 Driving Direction is Determined by Relative/Counter Relative Position Driving Command
The operation of counter relative position driving is the same as relative position driving except the operation which drives in a
direction opposite to the sign of the pulse number that is set in drive pulse number (TP). Command code for counter relative
position driving is 51h.