AnsweredAssumed Answered

LTC6804 PEC Errors when Daisy Chained

Question asked by John.Freeman@enersys.com on May 8, 2018
Latest reply on May 15, 2018 by John.Freeman@enersys.com

I have a question about the LTC6804.  I am in the process of developing a LabVIEW test program designed to communicate with several LTC6804’s in a battery pack. I am using 3 Part #LTC68041G-1 Demo Circuit 1894B. The SPI communications is done through a National Instruments NI USB-8451 SPI interface.

 

Up until now during my software development, I have only communicated with one LTC6804 using the LTC68041G-1 Demo board. I am now working on expanding the communication to two additional boards daisy chained from the first. Once I added the daisy chained boards I began to experience PEC errors

 

  1. I am experiencing PEC errors from the 2nd and 3rd boards when I attempt to read the AUX Register Group A & B and the Status Register Group A & B. The data being reported by 2nd and 3rd boards reads in-correctly all “1’s” while the 1st board in the daisy chain responds with valid data.
  2. I am NOT having any problem reading the Read Cell Voltage Registers, Group A through Group D using virtually the same code except with the command code changed to appropriate values to read Cell Voltage registers.

I have attached a screen shot of the LabVIEW code I am using to construct the command words to read the AUX registers. 

 

I am wondering if anyone that has used the LTC6804 has experienced this problem with daisy chained configurations.

 

Thanks,#

Attachments

Outcomes