5. Various Functions
5.2 Power-saving function
5-9 ME0342-4B
5.2.2 Auto Current Down Function
(1) Function selection parameter
Energized at a set current
(Note 1)
regardless of size of the external force for complete stop after
positioning operation, and when auto current down adjustment is not used. With the use of auto
current down adjustment, energization is done with consideration of the impact of external force,
so it is effective for reduction of power consumption when transported load is small, etc.
Note 1: Parameter No. 12 "Current Limit during Positioning Stop"
Set auto current down adjustment enable/disable with Parameter No. 182.
Parameter No. Name Unit Input range
at shipping
182 Auto current adj. select －
0
Relations of energization amount and speed command during positioning operation are shown
below for disabled/enabled auto current down function.
●Auto current down adjustment: Disabled
●Auto current down adjustment: Enabled
Energization amount
Speed command
Current limit during
positioning stop
Energization amount during stop with consideration
of impact of external force
5.2 Power-saving function
ME0342-4B 5-10
(2) Control with function enabled
1) The same process as the existing complete stop function will be performed until the
energization amount reaches current limit during positioning stop (parameter No. 12).
2) After completion of current energization during stop, the state is maintained until target
position deviation does not occur (zero).
3) In accordance with whether target deviation is present or not, the energization amount will
be manipulated.
• Without target position deviation, energization decreases by a fixed amount
• With target position deviation, energization increases by a fixed amount
The following restrictions are applicable for the manipulation of the energization amount.
• Decrease in energization amount ⇒ When process transition of increase is performed more
than a set number of times, only increase process will be executed.
• Minimum energization amount is defined per actuator basis, and without position deviation, it
allows energization amount to increase to the applicable amount.
• Maximum energization amount is current limit value during positioning stop (parameter No. 12),
and allows energization amount to increase to the applicable amount.
(3) Precautions
1) Difference in target position deviation depending on the encoder resolution
For actuator with lead length 24 [mm/r]
■ If the encoder resolution is 800 [pulse/r], it allows the energization amount to decrease until
target position deviation of 24÷800 = 0.0300 [mm] is generated.
■ If the encoder resolution is 8,192 [pulse/r], it allows the energization amount to decrease
until target position deviation of 24÷8,192 = 0.0029... [mm] is generated.
2) Precautions for high-resolution encoder
For an actuator with built-in high resolution encoder, when positioning complete status
continues for an extended period of time, even if this function is enabled, the energization
amount will eventually rise to current limit value during positioning stop (parameter).
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