Products > Test Equipment
Keysight's new 34465A (6.5 digit) and 34470A (7.5 digit) bench multimeters
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Kean:
0xfede I agree - but telnet just isn't really the right protocol for transfer of binary data.

It is important to remember (or discover) that telnet has a lot of history behind it trying to support so many different needs of another era - such as teletypewriters (tel-net as in "teletype network"), as well as raw, line mode, and even block mode (3270) CRT terminals.  And of course many systems back in the heydays of telnet could only really support 7 bit ASCII (or maybe EBCDIC), even if TCP/IP & telnet protocol required 8-bits.  Protocols like X/Y/Z-modem and Kermit were still heavily used for transferring text or binary files between wildly different systems, even after networks became commonplace.  Side note - I still know of companies using my Windows terminal emulator client & the embedded/automated Kermit file transfer features.

Beyond RFC 854 there is at least another dozen RFCs trying to nail down the specification for implementation compatbility, any subset of which may have been actually implemented (let alone tested) in a particular "host" (such as the 344xxA).  e.g. RFC 856 is specifically about binary transmission, and 1123 section 3.3.1 deals with EOL stuff which ISTR was a pain across the various Unix platforms I was dealing with many years ago (let alone echo and backspace weirdness).

Glad to hear that you seem to have sorted this out by using a socket connection instead.  :-+

Moral of the story: There is a reason the documents are called "RFC"s and not specifications or standards!   ;D
Echo88:
Just did a quick bias current measurement of my Keithley 34465A, just to check my new Triax-Banana-adapter-cable. Conditions: 10VDC, 10NPLC, AZ Off, Input Z Auto. Input-Voltage was 10...-10V, bias current measured with a Keithley 2500. Dont know if anyone can use this measurement, but i found it interesting.

Volt  Current
10   -7.4pA
9   -6.1pA
8   -5.0pA
7   -4.1pA
6   -3.2pA
5   -2.1pA
4   -1.2pA
3   -0.2pA
2   -0.1pA
1   +0.0pA
0   +0.7pA
-1   +1.9pA
-2   +3.3pA
-3   +4.7pA
-4   +6.0pA
-5   +8.8pA
-6   +9.2pA
-7   +10.9pA
-8   +13.9pA   
-9   +15.8pA
-10   +19.0pA
fonograph:
In dmm noise thread,High Voltage posted comparsion where both 34470 and keithley 7510 set to 10V DCV range and he is measuring warmed up stable reference.It shows 7510 gets stable in 40 seconds while 34470 needs 20 minutes to reach stability due to warm up.

Can someone do the same tests? I am specificaly curious if 34465 with its lm399 reference warms up faster.
fonograph:
How linear are the 34460,61,65 and 70 adc? I read on 65,70 brochure that they are 0.5ppm.Keithley 7510 datasheet shows 1ppm + 1ppm of range.

1. What is adc linearity of 34460?
2. What is adc linearity of 34461?
3. What is adc linearity of 34465?
4. What is adc linearity of 34470?
5. What is this "1ppm +1ppm of range"? I dont understand it,how is it different to just 2ppm linearity?

edit: I found another brochure,this one is from Testequity and it says 61 = 2ppm,65 = 1ppm,70 = 0.5ppm
Interesting,I thought they 65 and 70 have same adc,I tought only difference is that 70 have ltz1000,correct me if I am wrong but voltage reference doesnt have anything to do with adc linearity?

http://www.testequity.com/documents/pdf/keysight/34461A-34465A-34470A-ad.pdf

34460 isnt mentioned there,what is its linearity?

Kleinstein:
Even if they use the same ADC circuit, and maybe even the same board (except for the reference module), there can be still a difference in the parts used. This might not be visible, like selected better ones. Another difference that is not visible is a tighter testing: so the 470 might have gone through an extra test or a more stringent test to guarantee the 0.5 ppm linearity spec.

The LTZ reference in the 470 should not take so long to stabilize. It is more like other part on the board that need to stabilize to get full or near full stability. The amount of temperature drift can vary between units, so there can be better ones too.

The DMM7510 seems to use extensive temperature measurement and numerical corrections. This way the performance can be good, but not perfect even before reaching thermal stability. It might also be lower TC by itself. However the AZ Implementaion sucks and thus quite some extra LF noise.
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