Where can i find the sample code of Keithley 228A

[Daniel Hsu]

Please help me.....
I am a new user!
I'd like to use Labview to control the instrument (Keithley 228A voltage/current source) but i don't know how to write the sample code..

Please help me ! Thank you very much!

[GerdW]

Hello Daniel,

search at www.keithley.com for "228" and you will find the instruction manual. That will help you (see section 4).

[gagi1]

Hi Daniel,

Here is the link to the LabVIEW driver:

http://sine.ni.com/apps/we/niid_web_display.download_page?p_id_guid=E3B19B3E93FD659CE034080020E74861

Regards,
Vesna

[desmond tay]

Hi, I am using the keithley 228A to power up my device. But its seems that it required 1000ms to be input to the GPIB read (488.2 timeout), to display the current which is drawing by the device in the front panel. If i used less than 1000ms the current will not display on the front panel of my program. I need my program to run as fast as possible, if i input a 1000ms to the GPIB read, it will slow down my measurement. Pls advise. Thank.

[JohnM 64]

Hi Desmond,

What overall program are you using? Is this an example that came with the instrument driver, or one you created yourself? And does the GPIB Read timeout if you set the value less than 1000ms, or does it just not display the value on the front panel?

john m
Applications Engineer

[desmond tay]

HI JohnM_64,

the GPIB read does not time out when it was set less than 1000ms, it just show an empty string.

By right, it should time out and show an error messge right? If the power supply does not have enough time to feedback the reading.

Thank you

[JohnM 64]

Hi Desmond,

Yes, it seems like it would timeout from what you are describing, though I have no experience with that specific instrument.  It may be helpful to see what is going on at the driver level and see if any errors are occurring there.  To do this, we can use NI Spy to take a spy capture of the process.  If you have not done this before, here is a good document on using NI Spy:

Performing a Good NI-Spy Capture for Debugging/Troubleshooting

You can attach it to your next post and we can see what is going on.  And once again, are you using the instrument driver to program this instrument?  If not, are you simply doing a write and a read?  What is the overall flow of your program?

john m

[Fr34k]

Hello,

I programmed Keithley 228a memory steps of voltage and current and I started a single cycle memory control with labview. The program works fine and the machine gets all the commands and executes the steps, also measures the current and the voltage of the resistor its hooked on. but i dont seem to get all the readings. in fact the "GPIB read" only shows me the first value on the display. but not the next ones. i musnt paste my program cause its kinda confidential, but my steps are 1st: i write to the 228a's memory steps, 2nd: i set all the parameters so the programed steps execut, and 3rd: i read of the 228a.

parameters are: F0,P2,R0,G2,T4 and X ofc.

Hope someone can help, thanx.

[karshaw]

Hello,

This message is For Mr John M.

I have been working with the Ke 228 driver downloaded from NI site.  I could vary the voltage by changing the memory location 0.  The value that I have program are:

Memory#0, V=*** , I=*** , Dwell Time= 20s ,

I is chosen either 0.1, 1, 10 A 

Mode: Step, New Values. 

That way, I just had to reprogram V to have it immediately output on the device terminals.

Everything looks fine, when V and I   have the same sign.

However, I could not program the Keithley 228A  when the Voltage and the Current range have opposite signs. This means that the device should go to sink, but it did not.

Maybe it would go to sink if the load is a generator (such as a battery, I have not tried).

Note that this situation occurs only when programing the device (i.e.,  IEEE, Labview VI) but not when I enter my parameters from Front Panel  (Voltage and Current range with opposite signs).

Please let me know, what is the deal.

I appreciate it

Kar A