7 Set-up Procedure for Fully-closed Loop Control
7.3.2 External Encoder Resolution to Motor Feedback
7-10
7.3.2 External Encoder Resolution to Motor Feedback
The relationship between motor feedback position and external feedback position is dependent on the
mounted encoder specifications. So, the parameter below is used for the coordination. This parameter indi-
cates the number of external encoder period per motor rotation.
Note)
1. If there is a fraction, it is necessary to round off the decimal point.
2. If the number of external encoder period per motor rotation is not an integer, there is some error in the
speed loop. However, this is not relevant for the position loop. Therefore it does not interfere with the posi-
tion accuracy.
7.3.3 Encoder Pulse Output (PAO, PBO, and PCO)
Set the position resolution to Pn281. Set the number of phase A and phase B edges.
(1) Setting Example
"" shows the edge position. In this example, the set value is 20 therefore the number of is 20.
Note: The upper limit of the encoder signal output frequency (multiplied by 4) is 6.4 Mpps. Do not set a value that would
cause the output to exceed 6.4 Mpps. If the output exceeds the upper limit, the overspeed of encoder output pulse
rate alarm (A.511) will be output.
Example: The frequency is as follows if the set value is 20 and the speed is 1600 mm/s:
= 1600000 = 1.6 Mpps
Because 1.6 Mpps is less than 6.4 Mpps, this value can be used.
These parameters are used for position counting by upper controller. Sigma-5 SERVOPACK outputs the pulse
according to the settings.
If the application does not use this encoder pulse output (e.g. network application), the functionality can be
disabled by the parameter Pn081.1=1.
Important: C-pulse synchronizes to the edge of A/B-pulse.
Parameter Function Default Value When enabled
Pn20A Number of External Encoder Period 32768 After restart
Specifications
External encoder pitch: 20 m
Ball screw lead: 30 mm
Speed: 1600 mm/s
Parameter
Function Default Value When enabled
No. Dig.
Pn081 Application Function Select Switch 81 - -
1
Encoder Pulse Output Usage
0 After restart0 Enables the pulse output function (Pn281)
1 Disables the pulse output function
Pn281 Encoder Output pulses [Pulse edge/Period] 20 After restart
Phase A
Phase B
Encoder pitch
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