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Register | Bit 7 | Bit 6 | Bit 5 | Bit 4 | Bit 3 | Bit 2 | Bit 1 | Bit 0 |
|---|---|---|---|---|---|---|---|---|
CFGR0 Expected: | GPIO5 1 | GPIO4 1 | GPIO3 1 | GPIO2 1 | GPIO1 1 | REFON 0 | DTEN 1 | ADCOPT 0 |
CFGR1 Expected: | VUV[7] 0 | VUV[6] 0 | VUV[5] 0 | VUV[4] 0 | VUV[3] 0 | VUV[2] 0 | VUV[1] 0 | VUV[0] 0 |
CFGR2 Expected: | VOV[3] 0 | VOV[2] 0 | VOV[1] 0 | VOV[0] 0 | VUV[11] 0 | VUV[10] 0 | VUV[9] 0 | VUV[8] 0 |
CFGR3 Expected: | VOV[11] 0 | VOV[10] 0 | VOV[9] 0 | VOV[8] 0 | VOV[7] 0 | VOV[6] 0 | VOV[5] 0 | VOV[4] 0 |
CFGR4 Expected: | DCC8 0 | DCC7 0 | DCC6 0 | DCC5 0 | DCC4 0 | DCC3 0 | DCC2 0 | DCC1 0 |
CFGR5 Expected: | DCTO[3] 0 | DCTO[2] 0 | DCTO[1] 0 | DCTO[0] 0 | DCC12 0 | DCC11 0 | DCC10 0 | DCC9 0 |
Disconnect the cells from the AFE or turn off the power supply. Turn off the BMS carrier power supply.
Cell Measurements
Connect the isoSPI port A to a BMS carrier board.
Power the BMS carrier board with 12 V.
Connect the AFE to 12 cells in series.
Send two ADOW commands in filtered mode with PUP set to 1 (00000011 1101000) from the BMS carrier to the AFE over SPI/isoSPI.
Wait for about 500 ms.
Send the RDCVA, RDCVB, RDCVC, and RDCVD commands (00000000 00000100, 00000000 00000110, 00000000 00001000, and 00000000 00001010). The LTC6811 will send back 24 bytes, where each group of two bytes is the cell voltage, starting at cell 1 and increasing to cell 12. Store the result in an array, CellPU(n). The voltage of each cell is VCell(n) = CellPU(n) * 100 uV.
Send two ADOW commands in filtered mode with PUP set to 0 (00000011 1001000) from the BMS carrier to the AFE over SPI/isoSPI.
Wait for about 500 ms.
Send the RDCVA, RDCVB, RDCVC, and RDCVD commands (00000000 00000100, 00000000 00000110, 00000000 00001000, and 00000000 00001010). The LTC6811 will send back 24 bytes, where each group of two bytes is the cell voltage, starting at cell 1 and increasing to cell 12. Store the result in an array, CellPD(n). The voltage of each cell is VCell(n) = CellPD(n) * 100 uV.
Calculate CellΔ(n) = CellPU(n) - CellPD(n). If CellΔ(n+1) < -400mV for n<=11, then C(n) is open. If CellPD(12)=0, then C(12) is open.
Disconnect the cells from the AFE. Turn off the BMS carrier power supply.