Mitsubishi MR-J2S-A

[skywalker2058 1]

How can i change the resolution of the encoder from 4096 (default setting) to maximum 2^17=131072 pulses / second in my drive Mitsubishi MR-J2S-A. Parameter 27 mentions the formula but there is an extra 1/ 4 multiple that i dont need. in Parameter 54 i can put 0 X 0 X. 0 of MSB will get to output pulse setting as i dont need a division ration setting. The setting values of parameter 27 are from 1 to 65535 and after that it is divided by 4 which get me the value of pulses to 16383 which is not enough.

[panic mode 246]

encoder resolution is fixed by encoder design, it is physical characteristic of particular encoder and you cannot change that. and parameter 27 cannot not do that either (that's not what it is for). it is used to set number of feedback pulses per revolution that DRIVE sends to POSITIONER (this is not necessarily same as number of pulses that encoder sends to drive). positioner can be brick PLC with it's high speed I/O or dedicated card such as AD75P or A1SD75P or QD70P etc. as you have found, there are various limitations to this value. one of them is the size of register that stores parameter 27, the other is allowed transfer rate (i think some 1.3MHz or so, check the manual). this means that servo running at great speed may need lower PPR value sent from drive to positioner. positioner (in general) can be configured to interpret received pulse train as 1x, 2x or 4x, where 4x is best resolution you can get out of two square out of phase signals (two phases like two bits can have four values before repeating, hence 4 steps per one encoder pulse).

[skywalker2058 1]

Thank you man for your reply, so how can i verify that my motor HC-KFS73 has only an encoder of 4096 pulses/rev? (because encoder goes to drive and i can only see the output of drive)

[panic mode 246]

did you check the datasheet? i don't have time to look for it but catalog and datasheet should contain such info.

[skywalker2058 1]

Does the drive (MR-J2S-70A) has any control on the encoder output pulses (HC-KFS-73)? so if there are 4096 pulses per rev output, that is it, drive has nothing to do with it. because even motor tag says that its a 131072 pulses per revolution so does the datasheet.

[Crossbow 295]

J2S-A motors use 131072 ppr encoders.

[skywalker2058 1]

Yes but i am reading out only 4096 pulses per rev by that motor. and my question is that does the drive has anything to do with it? as Motor encoder goes to drive and drive gives out pulses for control via FPGA etc,,

[Matt 0]

Hi, Don't confuse the Servo Motor's encoder resolution with the 'Emulated' encoder output from the Amplifier. The MR-J2S range of Servo motors use an Absolute Serial Encoder with a resolution of 131072 ppr. The Amplifier has an output terminal to allow a pulse train to be fed out that corresponds to the encoder on the servo, however 131072 ppr is not possible. Using Parameter 27 you can configure a ppr of 1 to 65535. 4000 is the default.