NI Home > Community > NI Discussion Forums

LabVIEW

Reply
Active Participant
Daklu
Posts: 450
0 Kudos

More 8451 lockups

We have an 8451 communicating (I2C - 80 kHz) with a smart battery over several days while a test is being conducted.  Periodically the 8451 will lock up and quit responding with the indicator light remaining lit.  It requires a hard reset (unplug and replug) to get it to recover.  This is very similar to an issue I posted last year except this time there isn't another master on the bus.  The only two items on the bus are the 8451 and the battery chip.  It's not a hardware connection... the system works great after restarting.  Unfortunately I don't have any debug information to share yet; it occurs roughly once every couple days making captures somewhat hard.
 
Anyone have a silver bullet for this?  Failing that, are there plans to implement a watchdog timer in the v1.2 driver yet to be released?
Member
MXI Master
Posts: 193
0 Kudos

Re: More 8451 lockups

Daklu,

From what I have seen, faults such as this stem from the device under test. There is no way to know for sure in your case with out debugging of course.  Is there a chance you can capture a scope data when the device fails?
-Marshall R
National Instruments
Applications Engineer
One stop for all your NI-VISA Support

GPIB Support has a new homepage
Active Participant
Daklu
Posts: 450
0 Kudos

Re: More 8451 lockups

We are trying to capture a scope trace.  Given the infrequency of the event it's taking us a while...
Member sed
Member
sed
Posts: 2
0 Kudos

Re: More 8451 lockups

I am seeing the same problem.  I am trying to use the 8451 to log SMBus communication with a smart battery over a period of several months, but it will not even run for one hour without some sort of communications problem that the 8451 cannot recover from. 
 
I am running the bus at 32kHz, I have tried other frequencies but the problem seems to be frequency independent.
 
I have also tried making sure nothing else is using USB (on any port) at the same time in my program and that seemed to improve the time between failures. I am also using a NI USB-6210 for voltage & current measurement.
 
I am trying to capture the problem on a scope to work out what is going wrong.
Member sed
Member
sed
Posts: 2
0 Kudos

Re: More 8451 lockups

I think the problems are because the smart battery transmits the charge voltage and current every 20 seconds (and alarms when they occur) and the 8451 does not cope with a multi-master bus.

The solution is to tell the battery not to transmit/broadcast.  This is done by writing 0x6000 to the BatteryMode() (0x03) register in the battery to disable broadcasts.  This needs to be done at least once every 59seconds.  I am testing this on a LiIon battery I have designed that uses the Texas Instruments BQ2084-V143 fuel gauge. 

The vi attached is generic for writing to the battery, use an array as follows: 03 00 96 (all decimal).

Let me know if it works (or not!),

Cheers

Steve

 

Active Participant
Daklu
Posts: 450
0 Kudos

Re: More 8451 lockups

I'm glad you found a solution!
 
Our battery uses the TI bq27210 gas gauge and I'm almost certain (haven't had a chance to dig into it yet) it is operating in slave mode only--and the 8451 is the only other device on the bus.  I called NI last year when I was having issues with another test application and they assured me the 8451 is multi-master compatible.
 
The investigation continues....
Member
LCA2009
Posts: 2
0 Kudos

Re: More 8451 lockups

Hello,

 

I want to setup a communication between a BQ2084(smart battery) and a NI-USB-8451 device by using Labview. Does somebody can help me to start a communication? I'm looking for a small example to read out and write the serial number of the battery (or some other data). So with this program I can learn how it's working. Does somebody can help me?

 

Already thanks for reading my request, even more thanks if you can help me.

Member
Caleb_W
Posts: 90
0 Kudos

Re: More 8451 lockups

HI LCA2009,

 

While I'm not familiar with the smart battery, there are LabVIEW examples installed when you install the NI-815x driver.  They can be found by opening LabVIEW and going to Help»Find Examples then selecting Hardware Input and Output»I2C and SPI.  These examples will perform some simple I2C operations.

Caleb W

National Instruments

Member
LCA2009
Posts: 2
0 Kudos

Re: More 8451 lockups

Thanks for the information. I will have a look to this examples.


What I'm also notice is that the device NI-USB-8451 in Measurement & Automation not is shown as NI-USB-8541 but as 'USB0:0x3923::0x7166::0139FF91::RAW' under a grouping called 'USB Devices'. I've already installed the device on two different PC's, but on both it shows the same. Is this normal?

 

thanks,

Member
Caleb_W
Posts: 90
0 Kudos

Re: More 8451 lockups

Hi LCA,

 

Yes, this is the normal way that it appears.  You can set up a VISA alias for this device so it is named differently on this specific computer however. 

Caleb W

National Instruments