Actually I have problem to read out multiple port data N7745A with driver hp816x labview. There is no problem with single port. Can anyone provide advice?
With single port, I can manage to get the data after perform sweeping of laser.
However, when I enable two port power meter to read out measurement after sweeping of laser, only second port has data, the first port data is showing messy. Anyone has idea why this happened?
I had validated, the pre-setup flow seem like only recognized the last port setup, that why I only get the last port data.
Is there any method to get all port data correctly? The flow: pre-setup all port -> sweeping of laser -> read out all port data, with hp816 driver.
Urgent help. Thanks.
What functions are you using? Maybe those for Multiframe Lambdascan?
Possibly the application note and examples here can help.
Also have you compared with the LabVIEW example installed with the 816x driver? Especially example 5 is relevant to MFlambdascan I think.
I am using labview which converted from 816x driver. Where can I get the example 5? sorry I still new to labview.
By the way, I am using separate laser instrument.
The function I using is:
hp816 set PWM trigger configuration
hp816 set PWM logging
hp816 get PWM logging
If you mean that you are using a laser that is not from Keysight (or equivalently Agilent), then the Example 5, which uses the MFlambdascan functions that synchronize our lasers with the power meters, will not work for you. In any case, the examples for the 816x driver are installed in to a location like this:
C:\Program Files (x86)\IVI Foundation\VISA\winnt\hp816x\Examples
Probably you just need to make sure that you send the same trigger settings and same logging parameters to all of the ports on the N7745A, before triggering measurements on any of the ports. Then after the logging is finished simultaneously on all ports, you can get the logging results from each port by repeating the "get" function.
Ideally you can use the SME trigger mode so that the power meters receive a trigger for each sample of the logging series. That is how we usually set this up. I think you can find the necessary details in the application note that I linked above. You might also consider using the Command Expert sequences instead of using the 816x driver but the commands are similar anyway.
My trigger setting and logging parameter to all port is same like above and repeat for slot1-8. SME is triggering mode.
Then, I using "get" function to query port data. However, I always get correct data at last port. The others port data is something messy (-200, 93, -96.....). Did missing anything else?
I don't know what function is in the first box of each group above, but I guess the ports should be being set to the correct power range and automatic ranging should be disable.
I think it could be best to first have a loop that performs the functions of the first 3 boxes for each port.
Then after that loop you can use a separate loop to prepare the logging for each port.
And then after all of the logging is finished you need another loop to get the data from each port.
Maybe separating the loops like this is all you need to change.
Besides the application note mentioned before, the details in this one may help you too.
Thanks you. I can read out the multiport data correctly with setup triggering for each port, and read out data at the end. I loop the triggering for each port.
Retrieving data ...