AD2S1210 EVAL Board with SDP CB1Z: square wave position output

Greetings everyone!

Currently, I am using an AD2S1210 EVAL Board via SDP CB1Z board to decode a Tamagawa resolver. It seems everything is working properly, but the decoded position is a 0-90 degree square waveform rather than a triangle waveform. I am writing to ask if anyone can detect my mistakes.

Here is the boards:

Then is the EXC-/EXC, SINE, COSINE waves read by the onboard terminals (the waveform is weird because I was using my hand spinning the shaft):

The measurement of the waveforms is listed on the right panel. Vpp of the cosine and sine waves is around 3.5V.

Vpp of the excitation sine wave is 11.25V. 

The incorrect position output is shown below. Four square waves can be observed within one 360 mechanical degrees. 

Then I attach my configurations for the board for you to refer to. I am using the 10kHz onboard excitation so I chose the 10bits resolution and 10bits resolver resolution. For phase lock, I tried both 44 degree and 360 degree, but the result is still wrong. The fault detection part is independent from the decoding part. So I think my setting will not affect the decoding result. The numbers shown below are obtained after reading the manual. 

So please contact me if you spot my mistake from my setting! Many thanks!

My guessing solutions to the problem:

  • increase the amplitude of the SINE and Cosine waveform

I am not sure if the amplitude is enough for decoding. Its peak to peak value is 3.5V which falls in 2.2-4V.

I still tried to increase the excitation output so to increase the amplitude of the sine and cosine waves. No question occurred. 

The excitation gain is 1.54 when I received the board. Then I try to put the link on A and C. However, the amplitude of the excitation is lower at C compared to B. And I don't know where to regulate the R so as to change the gain when the link is at A. Can anyone answer my question here?

Then I changed the excitation driver from position A to B. However, the amplitude of the excitation does not change. The manual does not provide more information on the high current op-amp. I still adopt the default excitation driver which uses the AD8662. 

Thanks for reading my problem! I need your help urgently!

  • 0
    •  Analog Employees 
    on Apr 15, 2021 1:25 AM

    Hyacinth,

    Couple of things to check

    1) Make sure the RES1, RES0 settings on the evaluation board match your software setting in the control register of 10bits and vice versa.

    2) Let me know what resolver your using so I can check the wiring diagram against the connectivity on the RDC.   One thing to try quickly is reversing the polarity of your excitation connectivity to see if that helps the loop lock. This will account for the 180 degree phase shift coming from the inverting gain.   I'm not sure this is it but it is worth a try.

    3) It's interesting that you are getting a DOS MISMATCH fault, at least in the screen cap you sent.   That might indicate that something is off with the wiring in the front-end but I think that's unlikely.

    Let's see how you fair with the first two suggestions and let me know if anything changes with regards to the fault....Try reading/clearing the fault register a couple of times to see if you can get those fault LEDS to go out.   If so we are probably getting close.

    The next step I'll have you do is take me through your jumper connections so I can check them against the defaults.

    Sean

  • 0
    •  Analog Employees 
    on Apr 15, 2021 1:43 AM in reply to @skowalik

    Hyacinth,

    I did a little digging and the TAMAGAWA-SEIKI color pattern I found would seem to suggest the following.

    Lead Color Resolver Lead RDC Connection
    WHT REF1 EXC\
    GREEN REF2 EXC
    RED S1 COS
    BLACK S3 COS-LO
    BLUE S4 SIN-LO
    YELLOW S2 SIN

    Please note there are two types +type and -type so you may need to swap Yellow and Blue to get the correct quadrant of operation.  Is it possible you have the resolver miswired or is your wiring diagram different then this?

    Sean

  • Hi Sean,

    Thanks a lot for your help!!!

    Here is the feedback regarding your suggestions:

    (1) RS0 RS1 are in position C which means the resolution is controlled via J2. So it is only controlled by software, right? Position A and B are controlled by Vdrive and Dgnd, which is not my case.

    (2) You are absolutely right about the wiring issue. I swapped the cosine and sine wiring at first. Then I tried your suggestion, both blue(s4)-yellow(s2) and blue(s2)-yellow(s4). However, the position output is still square waves.

    (3) There are more faults than the DOS mismatch but only the DOS mismatch was captured by the screenshot. Sin/cos inputs clipped, tacking error, phase error were all witnessed when I did the test. I checked the wiring and make sure the connection is firm. So got no idea what caused the fault.

    This morning the fault detection configuration was left as the original ones, no error occurred this time (but still square positions). I have to doubt if it is my fault detection configuration that leads to the fault report. The orange light on the SDP board is on after I set up the fault detection part via software. Then I clear the fault many times as you suggested, the orange light then is off but the DOS mismatch error occurred again. Then I click "read" the DOS mismatch is flashing.  

    (4) All the jumpers are the default ones.

    • Power supplies are in position A that is the onboard regulator and finally by the 9V charger.
    • The excitation driver is in position A which is the AD8662 amp.
    • Excitation driver gain is in B which is 1.54.
    • Configuration pins are in position C. 
    • Digital interface options are in positions C(LK2 and LK2) and B (L1), which haven't been tested by me.

    So I got stuck again. Please indicate to me if you have any idea. Thanks again for your time and kindness!!!

    Best,

    Kun

  • You are right. I got some problem with the resolver at first cuz I don't have the type number or the series number. 

    The Tamagawa resolver I got is a variable reluctance resolver. There are white-green-blue-yellow-red-black wires. The rotor has 4 poles. Based on this I found a brochure from the Tamagawa website.

     It is a Singlsyn series lead type resolver. It should be the S21 series because I measure the diameter. 

    But the line colors are different from the brochure. I measured the connectivity and impedance of the six lines and decide the pairs, which are the same as you found.  The transformation ratio should be 0.286+/-10%, which is around 3.5/11. But the impedance does not match the measured ones. For the excitation winding, what I measured from the multimeter is around 30 ohms. The sine and cosine winding is around 60 ohms. They are way lower than the nominated values (120, 436, 436, respectively). Can you please share what you found for the resolver? Seems I dug into the wrong hole. 

    Thanks!!!

    Best,

    Kun

  • 0
    •  Analog Employees 
    on Apr 15, 2021 8:42 PM in reply to Hyacinth
    RS0 RS1 are in position C which means the resolution is controlled via J2. So it is only controlled by software, right? Position A and B are controlled by Vdrive and Dgnd, which is not my case.

    Let me get back to you on this but yes it should work that way.   To be honest I've done most of my testing with this part in 12-bit mode so I just want to make sure the evaluation software takes care of this automatically when you update the control word. 

    (2) You are absolutely right about the wiring issue. I swapped the cosine and sine wiring at first. Then I tried your suggestion, both blue(s4)-yellow(s2) and blue(s2)-yellow(s4). However, the position output is still square waves.

    So how do you currently have the wiring connected?  Is it per the wiring table I provided last evening?

    (3) There are more faults than the DOS mismatch but only the DOS mismatch was captured by the screenshot. Sin/cos inputs clipped, tacking error, phase error were all witnessed when I did the test. I checked the wiring and make sure the connection is firm. So got no idea what caused the fault.

    It is possible that on startup the device may indicate false faults which is why after RESET the first thing you should do is execute a FAULT register clear.  The fact that you are getting a DOS mismatch fault indicates that you have an imbalance in the SIN/COS voltages relative to what is preset by default.  Can you confirm that this fault light is only set after rotating the resolver.   That is with a static position it doesn't light correct?

    To be honest I'm starting to wonder if because of the miswiring if you didn't damage the RDC (not sure how) and if  on of the inputs isn't damaged.  What doesn't make sense is why you wouldn't get an LOS fault if a signal was completely missing so something is definitely not right..  Do you have another board you can try with the wiring connected correctly to see if you can't make it work?   If not you may want to contact your local ADI sales representative or distribution representative to see if you can get another one.   I've actually recently seen this type of behavior in our lab with a board only it turned out that it was our resolver simulator that was not outputting the AM sin wave and depending on the amplitude of the working channel the output would flip from 0 to 90.

    I would also recommend contacting Tamagawa directly to get a wiring diagram you can rely on based on the part number.  

    Let me know how things go.  We'll get to the bottom of this shortly and I will be back to confirm 100% the software driver works as it should once I've confirmed.

    Sean