Yuqi, Zihuan, Xiaoyu,
Please read my note below to Ehsan and and Connor regarding the LDV. This is expensive mistake number 2. We had something happen once already before you arrived to UT. You see why I am always worrying about the tools. Not only will this be expensive, it is possible the tool will be gone for several months during repair. This is what happened time before.
Do not use the LDV for any measurements related to the spark system. Also, No more LDV measurements involving amplifiers unless I am present (including AA systems, current amplifier, and RF amplifier).
Have a great vacation week,
Neal
Ehsan,
Connor told me about the blown reference channel on the LDV today, and we together confirmed it. As I am sure you anticipated, I am upset since this will be expensive and time-consuming to have fixed. I am not upset that you guys made an engineering mistake. Engineering mistakes are to be expected. Rather, I am upset at the protocol breach, and upset with myself for perhaps failing to accurately nail down that protocol. Protocol is supposed to protect the equipment from engineering mistakes that inevitably happen.
For measurements involving high voltage, you are to use an oscope to prevent this very thing. In a group meeting last week I had made this point to Zihuan regarding measurements with his sparking system. I remember elaborating on why high voltage is to be avoided for the LDV, reminding the team that those ports are calibrated to 1 microvolt precision. Even if the channels don’t blow in response to high voltage, high voltages can throw of calibration. You should only be using the LDV and its data acquisition when this system is necessary. If you were doing a first-of-a-kind ad-hoc measurement involving high voltage, why would you use a precision $0.75M instrument rather than an oscope when an o-scope would work just fine? O-scopes are expensive and damaging one is a shame, but still much less of an ordeal to repair than the LDV.
No more measurements with the current, voltage, or RF amplifiers for the time being and no more LDV system measurements until the three of us have a chance to work in the lab together. These measurements need to be very carefully thought through and planned. I will help with this.
One final note — I still don’t feel like I received a clear explanation regarding what happened. Please help me understand, perhaps using a schematic of the measurement and a hypothesis explaining how you think the reference channel saw a high voltage.