<p>Hello,</p>
<p>I have a Keithley 6430 (as a small current source) and a 6517B (as a picoammeter), and I want to connect one from another to do some tests. However, the triaxial connector conductor definition of these two instruments are different;(So I cannot connect them directly using a triaxial cable).</p>
<p>These definition are as follows (inner conductor, inner shield, outer shield):<br>
* Keithley 6430: (HI, GUARD, LO)<br>
* Keithley 6517B: (HI, LO, GUARD)</p>
<p>The previous method I tried is using 2 [triaxial-to-alligator-clip] cable, however the noise introduced by this connection seems to be large(about 1pA/sqrt[Hz] @ 0.1Hz) even with a shielding case.</p>
<p>To solve the above problems, I'm ordering a customized low-noise triaxial cable (6430 and 6517 HI-to-HI, LO-to-LO). There're two soldering plans, and I can't decide:</p>
<p>* 1st plan: 6430 connector direct connect to cable; 6517 connector's outer shield (Guard) disconnected, inner shield (LO) is soldered to cable's outer shield layer. (In this case, 6430's 'Guard' tightly surround 'HI', 6517's connector requires soldering).</p>
<p>* 2nd plan: 6517B connector direct connect to cable; 6430 connector's inner shield (Guard) disconnected, outter shield (LO) is soldered to cable's inner shield layer. (In this case, 'LO' tightly surround 'HI', 6430 side connector requires soldering).</p>
<hr>
<p> My questions are as follows:</p>
<p> 1. Which plan is better?</p>
<p>2. Can any of these plans work? (Are they worth to try? Any suggestions of selecting cable?)</p>
<p>3. If they can't work, is there a better solution?</p>
<p>Thank you!</p>
