Ty McKinney

Hello Eniola,
The 26XX line of SMU's do not take SCPI commands. We utilize a command set known as TSP (test script processor) which operates in a similar way. I'll link the reference manual below, see page 2-51 and on for sweep functions and there are examples provided as you read along. Specifically, see section 9 for all TSP commands.
Additionally, I would recommend downloading TSB (Test Script Builder) which will allow you to program and run commands remotely. In the navigator pane on the left hand side, you can find examples for a linear IV sweep example which would help you to start building and customizing your setup once you've read the sections I recommended above.

Here is the reference manual: Series 2600B System SourceMeter Instrument Reference Manual | Tektronix

Here is link to download TSB: Keithley Test Script Builder | Tektronix

Hello,
Zero check is a feature that notes the internal voltage offset within the unit. Zero correct allows you to algebraically subtract the internal voltage offset value from your measurement thereby correcting the value of zero within the instrument. Very similar to a REL function, however REL can be used to subtract out ANY level of signal or reading. Zero check/correct is specifically for correcting the value of zero by subtracting internal voltage offsets that would otherwise result in the instrument reading slightly higher than "true" zero.
Zero Check and Zero correct should both be done prior to making a measurement. Zero check willl be disabled to perform a reading.
See the manual I'm attaching below for more info. Ref pages 2-13 and on.
Model 6514 System Electrometer Instruction Manual | Tektronix

Kenneth,
Did the error first show after trying to update firmware or was this before?
What version were you on and which version were you upgrading to?
We have seen some issues when updating from older firmware to newer even though there is no hardware mismatching. I'm afraid this unit may need to be sent in to service for our team to look in to if this error does not go away. I'll attach the service link below just in case:

Use this link if located in the US: Service Quote | Tektronix
Use this link if located OUTSIDE of the US:Request Instrument Repair/Calibration for Tektronix & Keithley Products | Tektronix

Hello,

1. Minimum operating voltage in 4^th Quadrant as sink mode(or load mode)

We have same voltage accuracy in source and sink as the attached table(see png). We have 5 voltage ranges 100mV to 40V. In the minimum range 100mV, we have 5uV programing resolution but +/-(0.02% of reading + 500uV offset) for uncertainty which means that we can set or program 5uV but actual value sources with +/- 500uV uncertainty. This is voltage source mode case (CV mode).
The other case is that we can control output voltage level by compliance voltage in the current source mode. In this case, we have 10mV minimum in compliance voltage programing. I would not recommend the second case for accurate voltage sourcing applications.
 

2. Pulse Condition

Min/Max pulse width/rise time are very wide ranges depending on DUT impedance, source range and measure range. In the voltage source mode, we have usually about 300us ~ 1ms for pulse width. Please check out the datasheet for every individual case.
 

3. Output Off mode

If a DUT is an energy storage device like battery or solar cell, the output off mode must be high-Z mode. The default state of the instrument 2651A is 0V like ground. As soon as lead cables touch the DUT, the instrument should start to discharge the DUT. High-Z mode of output off mode prevents discharging issue in the DUT connection.  
 

Hello,
See attached link below and see bottom of page 2 for all parts and accessories for the 3723!
Model 3723 Dual 1x30 High Speed Multiplexer Specifications | Tektronix
Hope this helps

Hello,
Interlock is a safety feature designed to protect users from harmful levels of voltage. The amount of support I am able to offer in return is therefore limited.
All information regarding Interlock can be found in the 6517B manual. Reference pages 3-12 and on for more information.
Model 6517B Electrometer User's Manual | Tektronix
 

Hello Jeremy,
We don’t have an exact number for the sound noise, but we have noise with maximum load conditions under 80 dBA for 2604B. This is the safety requirement for sound level. We confirm that the instrument 2604B complied with the requirement. But we don’t have actual noise under 80 dBA in number.  

Hello,
You can program a 2450 SMU to sink current and measure voltage. See attached PNG for reference to the power envelope for this unit. If sinking up to 1A, you will be limited up to 20V, and if sinking up to 100mA, you will be limited up to 200V.
If you need to maintain a steady 1uOhm load resistance, your V and I will need to stay fixed. If your voltage changes for example, you will need to adjust the current appropriately. This can be done via custom programming but there will be a delay before establishing a dedicated constant current/voltage again as the unit sources and measures and adjusts to what you need. 
I would recommend using a dedicated electronic load unit capable of performing what you need, as these units are designed specifically for this application. See link below for an example unit that we at Keithley offer:
DC Electronic Loads | Tektronix

Hello,
See below link to another thread that should help! This covers all available information we have at this time.

GPIB-to-USB connection of Keithley 2260B-800-1 via TEK-USB-488 GPIB to USB adapter · Tektronix Community

I'm sorry about that. That product is no longer supported. The adaptors we can provide support with are our KUSB adaptors and a select few NI adaptors.
I would recommend using LAN or USB for your communication protocols. This will also negate any issues encountered while using adaptors of any kind.