Thread: using trigger with 8163A

Hi,

I am trying to use a santec tsl-510 sws laser with a 8163A to do a spectral scan of a device. I connected both with gpib, and used a bnc between the santec output to hp input. I can launch a sweep with the santec manually, and let the hp be triggered to take measurements. I have to use the santec has it has a range I need : 1510 to 1640.

My question is how to collect with gpib (using visual basic) all the power recorded by the 8163a after the scan. Could you please send me the GPIB command (FETC?,) to download all the power reading once the sweep is completed. also, what is the difference between complete and single measurements in the trigger menu.

thanks a lot for the help!

Bart

Thanks!

I tried to download the plug and play and to run the visual basic sample, but it said "hp816x_32.dll" not found.

Could you please send me the procedure to run it?

thanks,

Bart

Hello Bart,

A couple external items could be limiting the number of points, like the allocated array sizes in the program or the time allowed for the measurement before trying to recall the data.
But 43 does seem like a small number from this command. sens1:func:res:maxb?
So we should check whether something is very old on the instrument.

What is the 8163A firmware version?
What model power meter module is being used?
What firmware version does the power meter have?

The latest firmware can be found at this web site.
http://www.agilent.com/find/octfirmware

Best regards,
Mike

Hello Bart,

Thanks for the follow-up; it sounds like you are using VB6.0. I found the attached example using the PNP driver in VB6.0, here are a few more details on how to use the driver in VB6.0.

http://cp.literature.agilent.com/litweb ... 2790EN.pdf

Here is a link to the driver again

http://www.home.agilent.com/agilent/edi ... &id=112417

I have not had a chance to try the example recently as I would need to locate a PC w/ VB6.0 installed. Let us know if this helps and we can determine the next steps.

Regards,

John

Edited by: mkelly on Mar 15, 2012 9:38 AM

Hello Bart,

Thanks for the follow-up; I observe similar behavior using the power logging here. In general, we recommend putting the power sensor in manual range mode when using the logging function. Here are the commands you can use to perform the logging and also put the instrument in manual range mode.

You would want to use the SME triggering this will insure that a power measurement is ONLY performed when a trigger is received from the laser.

sens4:chan1:power:range:auto 0
sens4:chan1:power:range 10dbm
trig4:input sme
sens4:chan1:func:par:logg 2000,0.1ms
sens4:chan1:func:stat logg,star
trig 1
sens4:chan1:func:state?

LOGGING_STABILITY,COMPLETE

sense4:chan1:func:result?
sens4:chan1:func:state logg,stop

A few things to think about.

*Once the instrument is set to manual range mode the dynamic range of the measurment will be limited by the dynamic range of the power sensor. Some power sensors (i.e. 81636B and N7744A) have larger dynamic ranges (~ 55 dB) than the 81635A.

*If at some point more dynamic range is required you can use one of the power sensors above. Agilent also offers a driver which operates with one of the Agilent tunable lasers (i.e. 816xxA/B, 81940A/80A) which performs multiple sweeps and automatically decrements the power range during each sweep. The final data is stiched together and returned to the controlling program as a single array.

Let us know if this helps and we can determine the next steps.

Regards,

John

Hello Peter,

I guess you have either the 81940A or 81980A tunable laser for the continuous sweeps?
It would be best to trigger the power meter sampling from the laser itself for best synchronization.
After the command you use to trigger the sweep start, there will be some delay until the laser has accelerated to the chosen sweep speed and reached the chosen start wavelength where it would give its own trigger.

You can then also best use single measurement triggering so that each measurement point is synchronized with a laser trigger for which a measured wavelength value is then also logged by the laser's internal wavelength monitor.

For this you would use:
TRIG2:CHAN1:INP SME

And the laser output trigger is configured for a trigger at each step.
TRIG1:OUTP SWST

Probably you do not need to use the external trigger for starting the laser sweep, so you could use:
TRIG1:INP IGN
In that case the sweep will start when you give the command
SOUR1:WAV:SWE STAR

You will also need to configure the mainframe triggering to Loopback, so that the output triggers from the laser are input to the power meter.
TRIG:CONF LOOP

You should see on the display that the laser runs its sweep (however it has been set up) and then afterwards the response to SENS2:CHAN1:FUNC:STAT? should be LOGGING_STABILITY,COMPLETE

It is necessary to be sure that the laser sweep uses the same number of points as the power meter is set to log.
Also that the power meter averaging time does not exceed the time needed by the laser for each step, depending on the step and speed. Note that step here is only giving the chosen distance between triggers and the laser moves continuously. After the sweep, the lambda logging data can also be read from the laser.

All of this is a rather standard operation that is easier to program using the MFlambda scan function of the 816x Plug&Play driver. I haven't heard how this would be done with python though.

There is also the ready to use software available in the N7700A package. http://www.agilent.com/find/n7700
The IL Engine is free and does measurements like described here.

Best regards,
Mike

Hi Peter,
Probably we should take a step back and find out what instruments you are using?
What laser and power meter modules do you have?
It can also be good to make sure that the firmware is reasonably up to date.

Your use of the trigger output mode STF instead of SWST for the laser makes sense and is what I intended. But then the power meter should be able to log with SME if the number of steps and points match in your parameters.

But that assumes your instruments can do this, so we should first confirm that.

Mike

Hi Peter,
Thanks for checking. The power meter must be the 81635A?
Then both the instrument models and the firmware versions should be ok. Both modules could be updated, but I don't think that is causing your current complication. The 81980A now has version 4.84 and the power meter has 4.06.
These and the module update program for updating over the GPIB are available from the page
http://www.agilent.com/find/octfirmware

The 81635A should be able to log with averaging time down to 100us. One possible point: the dual power meter is a master/slave configuration, so if you are using only 1 channel it should be the master channel which is the top input.
Since you mention high numbers, maybe there is a problem with the signal being too high for the chosen range? For fast logging, you should not use the autorange mode but select a power range before sending the logging parameters.
Since the 81980A can supply quite high optical power, you probably need to use the +10 dBm power range and maybe also reduce or attenuate the laser power to below this level.
Otherwise are you able to get the correct values when you read the logging results in the binary block format? It may be necessary to adjust to the byte ordering format that is used: least significant byte. If the ordering is reversed you will generally see unusual and erratic values for the logging result.
Possibly either the range setting or the byte ordering is related to your difficulty? Also of course the number of points and averaging time should be compatible between the laser settings and power meter settings, but it looks like you're checking that.
Getting the real number arrays from the binary block can also be assisted by using the 816x Plug&Play driver mentioned above. A sequence of commands using this driver could be like follows and these commands can also be replaced with SCPI commands:
816x PnP command series for swept wavelength measurement

1. hp816x_PWM_functionStop(instrHandle, 3, 0)
2. hp816x_standardTriggerConfiguration(instrHandle, 3, 0, 0, 0)
3. hp816x_set_PWM_parameters(instrHandle, 3, 0, 0, 0, 1, 1500.0e-9, 100.0e-3, 10)
4. hp816x_set_TLS_triggerConfiguration(instrHandle, 1, 0, 2)
5. hp816x_set_PWM_triggerConfiguration(instrHandle, 3, 1, 0)
6. hp816x_set_TLS_laserState(instrHandle, 1, VI_TRUE)
7. hp816x_set_TLS_sweep(instrHandle, 1, 2, 0, 1, 50m, 1.55u, 1.555u, 100p, 40e-9)
8. hp816x_set_TLS_lambdaLoggingStateEx(instrHandle, 1, VI_TRUE)
9. hp816x_set_PWM_logging(instrHandle, 3, 0, 50m, Data_Points, Estimated_Timeout)
10. hp816x_TLS_sweepControl(instrHandle, 1, 1)
11. hp816x_TLS_sweepWait(instrHandle, 1)
12. hp816x_get_PWM_loggingResults_Q(instrHandle, 3, 0, VI_FALSE, 0, Logging_Status, Logging_Result)
13. hp816x_get_TLS_wavelengthDataEx_Q(instrHandle, 1, Array_Size, Wavelength_Data)
14. hp816x_set_TLS_laserState(instrHandle, 1, VI_FALSE)
15. hp816x_set_PWM_triggerConfiguration(instrHandle, 3, 0, 0)

Comments:
1. this is mostly to help program development, in case the PWM logging function is not finished.
2. this sets the mainframe trigger to “loopback” so the TLS step triggers are routed to the PWM
3. this sets up the PWM, the range and wavelength need to set here
4. this sets the TLS to output triggers after each wavelength step
5. this sets the PWM to use triggers for individual measurements
6. this turns the laser on
7. this sets up a sweep for a TLS in any slot (in this case #1)
8. This activates TLS lambda-logging. The “Ex” form is needed to use slot # >0
9. this activates the PWM logging function with the chosen averaging time, measurements wait for the triggers
10. this starts the TLS sweep
11. this waits for the end of sweep
12. this gets the results from the PWM
13. this gets the wavelength data from the TLS
14. this turns off laser
15. this sets PWM triggering back to default

Most of these details can be handled even simpler by using the MFlambdascan routine in the same driver.

You could also try using the IL measurement application in the N7700A software, at least to confirm that the hardware is working ok.
Both the driver and the IL application can be found from this site:
http://www.agilent.com/find/n7700

I hope one or more of these points help to move forward, otherwise let me know again.

Regards,
Mike