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BQ27742EVM: Battery Management Studio starting learning cycle problem

Part Number: BQ27742EVM
Other Parts Discussed in Thread: BQ27742-G1, EV2400, GPCCHEM

Hello.

I have a problem with starting of learning cycle when working with BQ27742-G1 + EV2400 +Battery Management Studio
After programming chemistry ID and calibration, I try to start learning cycle, but I have an error "The RUP_DIS/RDIS bit must be set ON to continue". What could be the problem? 

  • Hi,

      It means the RUP_DIS bit needs to be set "1" to start learning cycle. The bit is in Control_Status register as showing below: 

  • I understand that the bit RUP_DIS must be set before the start of the learning cycle. But I do not understand on which its value depends, and what needs to be done for this. Before learning cycle I sent RESET, IT_ENABLE and refreshed the registers state, and the RUP_DIS was set, but after starting learning cycle the error occurs.
  • issuing the Reset command before the start of the learning cycle disables resistance updates from occuring during that first discharge. You will want to have a qmax update occur first before resistance updates occur hence the need to issue a reset command before starting the first discharge cycle during the learning cycle process.
    thanks
    Onyx
  • The learning cycle does not begin regardless of whether Reset or IT is switching-on.I discharged the battery completely, left it to relax for 2h and tried to start the cycle. I show the status of the registers and the error window at the beginning of the learning cycle below. Maybe it can help to understand the cause of failure.

  • HI LJM

    Is there any reason why you are carrying out your evaluation process using hdq? Typically we recommend doing all evaluation and programming in I2C and conversion to HDQ should be the very last step.

    Given that the learning cycle add on seems to be acting up, i would recommend manually performing the learning cycle using the attached instructions.

    2451.LearningCycleOverview_.pdf

    thanks

    Onyx

  • We are in HDQ mode because we are going to configure the sensor on the HDQ bus in series production, in this case there is only one control line except power lines. In any case, according to the datasheet sluuax8, if fuel gauge is configured for HDQ communication - it cannot be reverted to I2Cmode. Is it possible to carry out a learning cycle in HDQ mode?

    I tried to carry out the learning cycle in manually, as recommended in the 2451.LearningCycleOverview_. I did the first two steps - sent IT_ENABLE, discharged the battery to empty, relaxed for 5 hours, but the VOC bit did not clear, but it had to be cleared.
    How do I know that each step of the learning cycle has completed successfully in the manual mode? Only by the values of the bits in the registers, right? By the way, the manual mode in the Learning cycle window also gives the same error, so I do all the operations manually and visually track the status of the registers in the registers window.
  • when doing the learning cycle manaully, you do not click the learning cycle button.
    You have to make sure you follow the instructions in your in write-up. Configure your settings correctly, notably, design capacity, taper current, chg and dsg current threshold, quit current, and use c/5 to c/10 discharge current rate. Also, make sure you have the the correct chem id programmed.

    If you have all that correctly done, you do not need to be bothered about the registers.
    The summary of the process is
    -Program chem id
    -set those parameters i mentioned above.
    -enable IT
    -issue a reset command( this will set the rupdis flag)
    -Discharge to empty using a rate between c/5 and c/10 .
    -rest 5 hours
    -charge to full
    -rest two hours
    -discharge to empty again using rate bw c/5 and c/10 and then rest 5 hours.

    at the end of this, update status will be 06.

    I hope this helps.

    thanks
    Onyx
  • I carried out the learning cycle manually as you said above. Update status bit was 4 in the first step of discharge to empty and relaxation 5h, and during charging step it was switch to 5, and after charging to full (FC=1) Update status became 6. Although it should be switch to 6 at the end of last step during discharging and relaxation 5h, right? Can this learning cycle be considered successful?
  • yes, your learning was successful.
    thanks
    Onyx
  • Ок, thanks for your help.
  • Hello.

    After successfully getting a golden image I have a problem. After writing the golden image to bg27742 the gauge is working  incorrectly as shown in the figure. What could be the problem?

  • hI,
    For starters, you are using an older firmware version. You need to update the firmware on your device to 1.03 in the link below
    www.ti.com/.../sluc558

    Seconldy, your temp measurements is looking inaccurate. Did you perform calibration of V,I,T?

    thanks
    Onyx
  • I updated the firmware version in the gauge with your file, then I updated  chemID, calibrated V, I, T , executed commands ITEnable and Reset. Then I made learning cycles  several times using GDK on I2C. Each time the learning cycle was completed successfully according to BqSudio, but  Update status = 4 and was not updated to 6. Is the chemID wrong maybe?

    Below there are the figures  at the end of the learning cycle after relaxation when OCV reading have taken

  • It's possible the chem ID is incorrect. Can you take your log files and submit them to our GPCCHEM tool to find the best match ID? The instructions are in the link.

    http://www.ti.com/tool/GPCCHEM
  • I have already performed the procedure of chemID and I sent my log file to that link GPCCHEM and I got the GPC_report file. Should I repeat the procedure of chemID again for more confidence?

    I performed another learning cycle with another chemID from GPC_report file, the Update status set to 5, but still did not update to 6 at the end of cycle.

    As far as I understand, the resistance table is not updated during the discharge, right?. There are the screens below

  • Looks like you got Qmax update, but not resistance update. Did you set the Ra flags set to default before running learning cycle? Ra0 flag 0xFF55 and Rax0 flag 0xFFFF?

    If they are set to default, send us your gg file and log from the learning cycle to debug the issue.

    What charge and discharge termination voltages were used for submit to GPCCHEM? It should be the cell manufacturer specified voltages, not your application's.
  • Yes, I set the Ra flags to default before running the learning cycle - Ra0 flag  = 0xFF55 and Rax0 flag = 0xFFFF. And I completed the chemistry cycle again and programmed a new value 0297 according to the received report.

    After the another learning cycle is completed, the flags are set to -  Ra0 flag  = 0x0055, and Rax0 flag has not changed. I was reading the Ra table during the learning cycle and Ra table values were modified throughout the cycle. But Update status = 5 and not updated to 6.  There are an attached log file of learning cycle and screenshots below

    lc_log1.log

  • Hi LJM
    Resistance table is supposed to get updated after a qmax update has occured. Did your qmax change? I would suggest cycling one more time, i.e rest charge to full rest discharge to empty rest without making any changes to data flash. At some point during the cycle you will have update status going to 06.
    thanks
    Onyx
  • I apologize for the delay in replying. I performed another learning cycle on a new clean chip. Parameter Qmax Cell0 has changed from 1000 to 3050, and the resistance table updates occurred. Update Status bit was set at 5 and did not change until 6 throughout the cycle. I did not make any changes to the data flash, just updated the chemistry. The device is working correctly, despite the fact that the Update Status bit = 5. Can we use the chip without setting this bit in 6?
  • Hi LJM,
    If qmax and resistance has changed, then you can change update status to 02. Extract a golden file and program on other gauges. After you program ensure to send the IT enable command to activate the algorithm. When you do so, update status will go from 02 to 06 on those gauges.

    thanks
    Onyx