Yaskawa Serial Encoder Testing

IDENTIFICATION AND CABLING

It is important to know exactly which model of encoder you are testing. Using the incorrect serial Yaskawa test selection will often provide poor results. The current Athena software cannot provide guidance as to which encoder selection to make, and the ENCODER ID field displays ----- for all selections.

The motor model is often the best way to identify which encoder is used. Please reference this article with help determining the encoder. 
https://support.mitchell-electronics.com/hc/en-us/articles/8432774627611-Yaskawa-Serial-Encoder-Identification

Please reference our Parts by Manufacturer list to find matching power and feedback cables for your specific motor: https://bobcat.mitchell-electronics.com/partsbymanufacturer

COUNT TEST

Perform the Count Test by rotating the encoder slowly by hand and make sure the results are green after each revolution of the encoder. If not, this could indicate the incorrect encoder selection or a faulty encoder. Like many other serial encoders, turning the encoder too fast under test can create count errors.  

INC ENCODER COMMUTATION TESTING

All serial Yaskawa singleturn encoders listed as INC (except for the newest 24 bit INC) will display commutation pulses. Turn the encoder slowly and make sure each UVW state changes from H to L, and that they should never be all in the same state (HHH or LLL). If so, this could indicate you have the wrong encoder selection made, or the encoder is faulty. 

You can also check the alignment using these commutation pulses.

The standard toggle state should be:     U      V     W

                                         +U -V -W =    H/L   H     L     at 180E degrees. 

REV COUNT TESTING

Both singleturn INC and muliturn ABS encoder selections will contain a revolution counter. The REV COUNT field should increase by 1 count in the CCW direction, and decrease by 1 count in the CW direction every time the encoder passes through 0 mechanical degrees. Make sure to turn your encoder several times in each direction while keeping an eye on the REV COUNT field for proper functioning. 

The number of rev counts is different for each encoder selection. All serial Yaskawa ABS encoders will have 16 bits of rev counts (0 - 65,535 turns). The serial Yaskawa INC encoders have different rev counts depending on the encoder type. See the table below. 

Enc Type            Revs

13 bit INC   ---   2   (turns 0 - 1)  

16 bit INC   ---   8   (turns 0 - 7) 

17 bit INC   ---   8   (turns 0 - 7)  

20 bit INC   ---   8   (turns 0 - 7)

24 bit INC   ---   16 (turns 0 - 65535)

ENCODER ALIGMENT

The Yaskawa serial encoder standard alignment should be:

+U-V=150E

+U-W=210E  

Motor forward direction:    CCW

Encoder forward direction: CCW

The serial encoders are typically keyed to the motor shaft at the factory. The keying style depends on the on the encoder type. The keys are typically brass or gold colored and are pressure fit onto the motor shaft. Regardless of the physical key type, the general rules apply. If the key on the motor shaft remains at the factory setting, then the encoder should go on correctly aligned. However, we have seen many instances where the motor key position gets disturbed. This then becomes a much more difficult job as you will have to correctly set the key position on the motor shaft. This often requires lots of trials, connecting the encoder and locking up to check alignment, then removing and adjusting the key and repeating the process until the angles are correct.     

ERROR TYPE TESTING

Athena currently displays an ERROR TYPE field to show errors from the encoder. This is still in development. Here is what we have determined so far:

1. All serial encoders in good working order should display (0x0001) by default. The alarms are additive, so a battery alarm of (0x0004) plus the default alarm of (0x0001) would be displayed as (0x0005). 
   
   
2. The battery alarm (0x0004) will be present for all ABS encoders without proper voltage connected to the free battery wire on your test cable. The display for a disconnected battery should show (0x0005) and then should clear to (0x0001) when voltage is applied to the battery wire. Simply jumper the free battery wire to J1 pin 1 (+5VDC) for a quick test.  
   
   
3. The INDEX alarm (0x0240) for INC serial encoders will show as (0x0241) when first powered on, then clear to (0x0001) when the index is seen while rotating the encoder. This will also cause the INDEX field to go from ALARM to OK. 
   
   

ENCODER MEMORY

The encoder stores memory which contains the full motor model and encoder model, at a minimum. Below is a screenshot from the Yaskawa drive which reads this information from the encoder. 


We currently do not have support to read the memory. This means that if you are replacing encoders, take caution to only use replacement encoders that came from the same exact model of motor.