Synching Keithley6221 Ac source with SRS830 Lock-inamplifier for 2nd harmonic measurements

Hi,
I want to sync keithley 6221 Ac source with SRS830 lock in amplifier.I want to source sinusoidal AC current with an additional phase difference 90 deg to my test sample and then I want to measure the 2nd harmonic voltage from my test sample using Lockin amplifier. I understand that for synching we have to connect the trigger link port of AC source with the reference of Lock-in but which I am not getting which pin(1-8) has to be connected.Also how do we make sure that the frequency and phase are locked for both of them?Please let me know about it.

Hi, 
If you were using 6221 with 2182A for delta mode then you will be connecting both the instruments with one RS 232 and a trigger link (8pin circular) connector. That's  the 8 pin trigger link connector at back of 6221. There are few pin distribution box available to purchase or can be made in lab by cutting the trigger link cable. Please see the available literature available on internet which pin to use. Probable you have to connect pin 1 or 5 or 8 to trigger in in the front panel of  your SRS. Then you can adjust the phase difference from there.

Bests.