Hi, Mickle T,
I directly short the GUARD port with the other 4 port together and re-calibrated the zero front , and the zero offset is around 1uv and it is not so stable runing from 100nv to 4.5uv range. The meter has warmed up for about 8 hours.Is it fine?
When I measure the input signal, I just connect the HI and LO port to the 6144 source with the normal test line , the reading is also running in the last 2 digit ,2.0-3.0uv at 10v input. I know it might causing by the source noise, but how can I evaluate the noise performance of the meter? In my view , the 8.5 digit meter should keep stable in the uv digit and jump on the nv digit, right?
I have made a LTZ1000 reference board and does it can be used to evaluate the noise performance of the meter?
For running the LTZ1000 board about half an hour, the 10v output has max 2.0uv jumping range in 8.5 digit mode, and the A-ZERO is open and plc=20. Is it aslo fine?
More information, if I go to the diagnostic menu and measure the internal 7.2v reference , it is also jump about 2-3uv, in the last 2 digit range. It is fine? The meter is power on for 11 hours till now.
Best Regards,
szszjdb