new DP832 needs calibration in 45 days ? - Page 1
Forum section: electronics / testgear

author: danny_isr
author_rank: Regular Contributor
timestamp: March 30, 2015, 01:03:21 am
content: So i received my DP832 a week ago, i look at the calibration document and it was done on 11-May-2014.If those things need calibration every year, what is the point to sell it just before it needs calibration again ?Should i contact the dealer for this ?thanks

author: Paul Moir
author_rank: Frequent Contributor
timestamp: March 30, 2015, 02:57:10 am
content: I would, if you need a current traceable cal. Anything more than 6mo would raise eyebrows.If not, who cares?In some businesses, the factory cal isn't acceptable and a fresh cal is done right away. This is especially true if the factory cal doesn't refer to the specific transfer standards the equipment has been checked against. This is because traceability and the possibility of recall is lost. So sometimes - I should say often - the factory cal is worthless anyway.

author: Fungus
author_rank: Super Contributor
timestamp: March 30, 2015, 02:55:43 pm
content: Quote from: danny_isr on March 30, 2015, 01:03:21 amIf certified calibration is important to you then the factory calibration isn't worth much anyway - it should be calibrated after transportation.If not, it will be fine. Those things don't really drift much. Obviously you should check it against your best multimeter before use but the yearly certification/calibration requirement is mostly about ass-covering in case of disaster.

author: dadler
author_rank: Unknown
timestamp: March 30, 2015, 07:20:15 pm
content: On this note, I have a question on the calibration of the DP832.I have never calibrated mine (purchased Dec 2014), but when the channels are off they show a non-zero potential vs across the +/- terminals. For example, on channel 1, I see -3mV across the output terminals with the channel off.This does not really bother me as it's sort of normal with these units. However, this happens to match the exact output error between the requested output voltage and sense voltage on then DP832 display. If I request 12V on channel 1, I see 11.997V on the sense output on the display with no load.I have the equipment to calibrate the unit, but only want to try it if there is a chance of it solving the issue. It seems that since the sense output knows very well that the output is not exactly 12V (11.997V), that calibration might not address the issue. The error delta is also different across channels, which again makes me think that calibration may not help.Anyone know?

author: McBryce
author_rank: Super Contributor
timestamp: March 30, 2015, 07:35:17 pm
content: Mine does about the same (it's about 4mV on mine), but I've measured the outputs with a recently calibrated Keithley 2000 and it's the display that out on mine, not the output. The voltage was spot on, the DP measurement is off.McBryce.

author: dadler
author_rank: Unknown
timestamp: March 30, 2015, 07:54:43 pm
content: Quote from: McBryce on March 30, 2015, 07:35:17 pmI've measured with a brand new 34465a, brand new Brymen 869, and about a year-old Fluke 287. All show ~11.997__ and the DP832 reads 11.997 sometimes fluctuating to 11.996. (Meter displays seem stable at 11.997.) this is on Channel 1. The others do the same thing but the offset is different.Off-topic Side note: the fans on my DP832 make a soft-yet-harsh bearing/rattle sound when they spin up fast at boot-up, then slow down at the ugly sound goes away. Sounds like a semi-dying PC fan for a few seconds. And my LCD display is tweaked (not installed perfectly straight). I was tempted to swap the unit when I got it but figured this was normal with Rigol QC. The other Rigol products I have since purchased are flawless so I sorta wish I had swapped the DP832. Oh well.

author: Len
author_rank: Frequent Contributor
timestamp: March 30, 2015, 08:49:58 pm
content: Quote from: danny_isr on March 30, 2015, 01:03:21 amThis is pretty normal. You can't really expect Rigol to control how long it takes its distributors to sell their stock.Strangely, my Agilent multimeter's cal certificate had a note saying that you can just ignore the time between when it was calibrated and when I bought it.I guess Agilent/Keysight expects their distributors to store their products in time-stasis warehouses .

author: Wim_L
author_rank: Regular Contributor
timestamp: March 30, 2015, 10:20:37 pm
content: Quote from: Len on March 30, 2015, 08:49:58 pmOr maybe they checked which things influence calibration, and found out that the instruments don't change much when stored in reasonable conditions, and that drift is mostly happening when the instrument is active. Especially for instruments that did not get a long burn-in/ageing at the factory, that could be correct.

author: danny_isr
author_rank: Regular Contributor
timestamp: March 31, 2015, 02:31:22 am
content: well i guess i will live with iti did notice on mine the same problem on channel 1. The reading via the sense is slightly off, though the out put is dead on. kind of weird if you ask me.i was measuring exactly 1.000v output on a fluke, but the 832 reported 1.01v... channel 2 and 3 don't have that offset.So when you buy the upgraded accuracy, does it display one more digit or it's actually more accurate by one more digit ?