Problem- Linear Scale

[xavierdemoura]

Anyone put Fagor linear scales TTL in a Mitsubishi M70 control ??? I need put this scales in Litz Machine and i was having some problems like compatitbility and parameters !!!

Thanks in advance

Daniel

[girishdk]

Hi,

You need to collect the following data.

1) Confirm that the Scale works on +5V supply, maintain the required cable resistance & other specifications, so that the drive side power supply is not overloaded.

2) Type of the servo drive (MDS-D-SVJ3 or MDS-D-V1/V2).
Attached is the drawing for SVJ3, i think it is same for V1/V2.. also.

3) Because the scale is TTL(ABZ) / Differential (AA'BB'ZZ'), it is Incremental.
So check if the machine is presently having Absolute or Incremental encoders on motor side?
If Absolute, whether there is Home Limit Switch & Dog for referencing?
If not it will be required to be provided.

4) What is the resolution of the scale in 0.5 / 1 / 3 micron OR pulses / mm.

5) What is the axis Gear Ratio (or Par. 2201(SV001) & 2202 (SV002).

6) What is the Ballscrew pitch (or Par. 2218 (SV018).

7) If the Motor Encoder feedback polarity & Scale feedback polarity is same or opposite?
This can be found & adjusted later also.

8) Parameters required to be adjusted.

8.1) #2049 - 0 - Home position setting method.
8.2) #2217 - xxnx - Encoder/Scale feedback polarity & Abs/Inc Encoder type.
8.3) #2219 - xxxx - Speed feedback kp/pitch.
8.4) #2220 - yyyy - Position feedback kp/pitch.
8.5) #2225 - 8xxx - Scale, Encoder & Motor type setting.


Best Regards,


Girish

[xavierdemoura]

Girishdk,

Thanks for your attention.

1) The Fagor linear scale is type MX. It´s TTL 5 V.
2) The servo drive is MDS-D-SVJ3
3) The motor has absolute encoder. I change the system to incremental and increase dog to reference and limit
4) The scale resolution is 4 micron
5) There isn´t gear elation. The motor is connected directly in the ball screw
6) The ball screw pitch is 12 mm
7) About the polarity. What´s you are tell me ??? Is about the movement ??? CW or CCW direction ???
8) The prm 2225 i adjust to 8207. The original prm is 2207. No problem. My problem is to adjust prm 2219 and 2220. If i follow the manual, i have some problems. You have some idea ???

Thanks

Daniel

[girishdk]

Hi,


7) About the polarity. What´s you are tell me ??? Is about the movement ??? CW or CCW direction ???

You can see the difference between Motor encoder & scale feedbacks in the Servo Diagnosis screen. The title is "Error".
When you move axis in 1 micron by handle, if the error keeps on increasing, that means the feedback polarity of scale is opposite to motor encoder. Then the par #2217 needs to be adjusted. What is the value of #2217?


8) The prm 2225 i adjust to 8207. The original prm is 2207. No problem. My problem is to adjust prm 2219 and 2220. If i follow the manual, i have some problems. You have some idea ???

Please check if you have
a) retained the original value of #2219. i.e. ppr of motor encoder for speed feedback
b) Set #2220 = 3 (i.e. 12000/4 = 3k pulses per pitch)


Best Regards,


Girish

[xavierdemoura]

Tomorrow i will try and tell to you.

Thanks

[girishdk]

Hi,

Some more details for you as attached,

You can check the feedback from motor detector, Scale. For this you can go to the attached Drive monitor page & then page down.
Check Motor end feedback, Machine end(Scale) feedback & the Feedback Error. This will give idea regarding the polarity of both feedbacks.

Also the in scale data they have one is resolution & another is accuracy. Accuracy is normally given as +/- xx, this is different from resolution. Please confirm that the 4 micron given is resolution only.
Otherwise the value of 2220 will be different.

Best Regards,

Girish