Temperature Related VIM Issues ?

[JTG Engineer]

We have experienced two (2) seperate issue with the analogue channels on the VIM (serial # 193 and # 114) stopping working after they have been on the race car at least two (2) hours into the session.

In the first issue, VIM # 193 functioned correctly for five (5) outing and on the sixth outing (6th) outing all of the analogue channels (AV F1 - AV F6, and AV H1 - AV H8, and AV S1 & AV S2) stopped recording. We swapped VIM # 142 for VIM # 193, and the above listed channels we were recorded, however the same channels that were working when VIm # 142 was at the rear of the vehicle did not function when VIM # 142 was moved to the front of the chassis and VIM # 193 was used to replace #142 at the rear of the chassis.

VIM # 193 had been used to test at least three (3) seperate times prior to the malfunction.

We returned VIM # 193 to MoTeC East for their inspection and analysis. A Firmware Upgrade was effected, and the VIM was returned. Unfortunately, this did not resolve the issue with VIM # 193.

In the Second Instance, a replacement VIM (# 119) was utilized instead of VIM # 193 at the front of the Chassis. Ten (10) outings were completed with all channels being recorded. On run # 11, the same AV channels, as described in instance # 1; did not record, at that point the internal temperature of the VIm # 119 was 82.5 Degrees C. As time was limited, we reconfigured channels AV S1 & AV S2, to be recorded as SDL Channels, and they were successfully recorded for outing # 12, as well as the other AV channels that had failed on the previousv run. Run # 13 we reconfigured the Front VIM # 119 to once again log the SV 1 & SV 2 channels, however for this run we cooled th VIM down to 45 Degree C. The VIM #119 logged all AV Channels succesfully the balance of the day thur run # 25. However, we would cool the VIM done to approximately 50 Degrees C between each outing.

When tested on the Bench, VIM # 119 has not exhibited any of the channels not being logged, even when heated with a heat gun to inexcess of 85 Derees C.

Any thoughts as to what might be causing two (2) different VIMs to malfunction?

Thank You

[figgie]

JTG Engineering

it does sound like a temprature related issue.

I would venture a guess that a heat sink like used for CPU's in the computer world might help control the tempratures and keep the tempratures a bit less hot than the 85c that you saw. If you put a +12vdc computer fan on the heatsink it will help further.

[JamieA]

could you please send me a log file of this problem so that I can look into it further....

thanks.

jamie

(jamie.augustine@motec.com.au)

[incontrolsteve]

I have run vim's over 90 dec C (not really recommended!) for over 6 hours without any problems in the past.

[JamieA]

With a VIM, the max ambient temp is 70c, max internal temp is 85. There are some components within the VIM that the suppliers dont recommend over that temp, so we cant recommend running it above that temperature, although it may still work..

So your temps seem acceptable, although quite high. The answer is probably going o be a little tricky. It would be good to see some data from when it happened so that we can look into the problem further..

Jamie