Actually I do want better CAT ratings on bench meters. I may be 60 but I still remember the stupid things students do in tech classes. The idea that they are marketing this as a solution for education is what prompted my post.
However in industry, at least the one i work in, "bench" meters do go out onto the plant floor very regularly. In this case they are either used for calibration+validation or in some cases diagnostics. Generally they should never get close to high energy circuits but it does happen. Recent enforcement of regulations for arc flash safety has equipment coming in such that the process control stuff is separated from the heavy 3 phase stuff, usually in separate cabinets. That makes the meter use "safer" but a better CAT rating would be very welcomed.
Further if you are at the bench you may have three phase hardware you are working on. This honestly doesn't happen much today due to the lack of time which leads to a lot of "stuff" going into the recycle bin. I'm not real thrilled about this but there is little I can do about staffing because personnel says they can't find candidates.
As for safety I'm not sure how it became a specialty need. Also fused connections are not a guarantee of safety. I've seen some strange things over the years when it comes to what appeared to be properly installed hardware.
For starters its the fuses. A HRC fuse is more expensive. And the enclosure is different. If a fuse blows up in a multimeter, which is in your hand, you might loose a finger. If it blows up in a desktop DMM, worst case you might need to change the pants.
Its much worse, that they might melt the isolation of leads or set them on fire before any of the fuse would act.
And there are practical reasons for this. Unlike a 3.5 digit DMM, here we are dealing with precision. It's only 5.5 digits, but it comes from the same family as the 6.5 and 7.5 digit Agilents. Its entirely possible that there is tradeoff between accuracy and safety, and I give you an example.
Take an ordinary relay, and try to measure 100 mv with it. When you do that with a 6.5 digit DMM, you realize that the energized coil will heat up the connection of the relay, and you have a bunch of tiny thermocouples everywhere in it. You can either use a latching relay (not safe), Analog switch of FET to switch the signal (not safe), wet contact mercury relays (kills polar bears, somehow) or high end relays that dont fit in the budget.
Students do a lot a crazy things. It is even easier in Europe then in the US: the standard 4 mm plugs nicely fit many European power outlets.
Isn't it that way by design?
I can appreciate the new kind of housing, it saves a lot of space on the workbench (depth).
Prices are better for hobby purposes but what when Keysight doesn't sell to private persons anymore...
Thats what distributors are for.
I didn't realize it was a fashion show!
If you want 6.5 digits, BK has the 5493C. I don't know where you are looking at prices, but the 5493C will be more than the GW-Instek--it's twice as accurate.
just out of curiosity, who is going to calibrate that meter for you? Just as an example, the 34465A has 2 year specification, so you need to calibrate it half as often (if you can live with the accuracy). So while it might cost more, at 3 or 5 years, the cost breaks even.
Home
Help
Search
Login
Register
