NISCOPE_ATTR_ENABLE_TIME_INTERLEAVED_SAMPLING Attribute Read Error

[MarkL@Hon]

Using Labwindows/CVI niScope function panels to narrow down an issue I am having with the attribute.

Using niScope 3.4.16 (I understand it is an older version.  I am not supposed to update unless I can prove it has a needed fix)

Using an NI PXI-5152

I do an init

I do a read of the attribute default value.

I then write it to true (1)

I then try to read it back and get a run time error of invalid param.

I have tried using channelList of "", "0" and "0,1"

If I never set it or set it to 0 I can still read it back.  I just get an error after I set it to true.

I am attaching screen captures of the steps.  Filenames are in the order I executed.

[Stephenah]

On the 5152/5153/5154, if you set NISCOPE_ATTR_ENABLE_TIME_INTERLEAVED_SAMPLING to true you must set NISCOPE_ATTR_MIN_SAMPLE_RATE to a TIS rate.  The only valid TIS rate for the 5152 is 2.0 GS/s.

[Lea_D]

Hi MarkL,

What Stephenah says is correct. It's also verfied on page 9 of the specifications manual and is single chanel only so "0,1" won't work. Good luck on the rest of your application and thanks, Stephenah!

[MarkL@Hon]

I set Min Sample Rate to 2GS/s and get the same error.

Can you give me a list of values that need to be set to configure the scope for TIS?

I do:

niScope_init ("PXI-5152_6", NISCOPE_VAL_TRUE, NISCOPE_VAL_TRUE, &_tmp1);

niScope_ConfigureAcquisition (_tmp1, NISCOPE_VAL_NORMAL);

niScope_ConfigureVertical (_tmp1, "0", 10, 0, NISCOPE_VAL_DC, 1.0, NISCOPE_VAL_TRUE);

niScope_ConfigureHorizontalTiming (_tmp1, 2000000000, 200000, 50.0, 1, NISCOPE_VAL_TRUE);

niScope_SetAttributeViBoolean (_tmp1, "0", NISCOPE_ATTR_ENABLE_TIME_INTERLEAVED_SAMPLING, VI_TRUE);

niScope_GetAttributeViBoolean (_tmp1, "0", NISCOPE_ATTR_ENABLE_TIME_INTERLEAVED_SAMPLING, &_tmp6);

What am I missing and/or what am I setting wrong?

I am very new to this and am having trouble with the proper programming protocol.  I don't understand why it allows me to set an invalid value and only give me an error when I try to read it back (or gives me values of 0 when I try to take a measurement).  I am having the same issue with Vertical Range.  It does not give me an error if I set it to an invalid value (e.g. 200 for the 5152).  Why wouldn't it give me an error when I try to set it to an invalid value.  And yes, I have range checking turned on.

[MarkL@Hon]

I would like to rephrase my questions to the following:

1) Can I get a CVI based sample project that correctly initializes a PXI 5152 scope for TIS?

2) Is there a way to get an more definitive answer (via a query or some other way) to know what "parameter or property" is invalid when an 0xbffa010 is received?

3) Is there a way to configure/enable an error response when setting an attribute to an invalid value (e.g. vertical range and max input frequency)?

Thanks,

[Stephenah]

1) There is a generic CVI example that ships with NI-Scope, it has most of the properties you need to configure to get up and running.  On Windows 7 it installs to C:\Documents and Settings\All Users\Documents\National Instruments\CVI\Samples\niScope\ConfiguredAcquisition

2) Most of the errors that NI-Scope throws will have more informative text and will specify the attribute or value that is invalid.  Unfortunately The particular error you are running into is not that specific.

3) I'm curious what you mean by "configure/enable an error response", could you elaborate a bit more?

Just so you know NI-Scope waits to validate attribute values until compile, initiate, or a get attribute is called.  This is because many attributes interact and its possible to specify an attribute value that is invalid when it is set but becomes valid once another attribute is changed.  For example on the 5122 20 V is a valid vertical range but only when the impedance is set to 1MOhm.  If the device was set to 50 Ohm and the range was changed to 20 V NI-Scope will not throw an error until commit, initiate or a get attribute is called. In this case its possible for the impedance to be changed to 1MOhm and the configuration is considered valid.

I hope that helps.

Stephen

[MarkL@Hon]

Stephen,

Thanks for sticking with me on this.

1) I am able to get the scope setup to capture signals outside of TIS mode as the generic sample does.  I "think" I am setting everything right for TIS and when I set NISCOPE_AT​TR_ENABLE_​TIME_INTER​LEAVED_SAM​PLING to VI_TRUE and then read it back I get an error.  I also find that when I set this attribute to VI_TRUE I get an error when I read back Max Input frequency.  It doesn't seem to matter what I try, I get these errors.  I was hoping NI would respond by giving me a sample project that configures the scope properly for TIS.  That way I can see what I am missing.

2) Yes, most other error messages are better.  This is the one that I am struggling with.  It seems to be telling me that a property of the scope object is wrong but doesn't tell me which one.  It is not necessarily the one that I am setting/reading.  I was hoping to find the magic decoder ring that tells me which one it doesn't like OR tells me which ones are dependent.  Your response about how the validity of an attribute can vary based on other settings is probably why it does not give specifics.  I guess I just need to gain that experience but again, I a keep thinking there is some document that I haven't seen that explains all of these dependencies.

3) I was talking about wanting to see an error when I try to set an attribute to an invalid value.  Again, your discourse on how some attributes may be invalid when set but become valid based on other settings partially explains this.  I was hoping to see an error message if setting to a value that would never be valid.  Like setting vertical range to 2000V or Max Input Frequency to 800MHZ.  My CVI generated DLL driver wrapper supports several models.  The Teststand sequence developers are "porting" scripts to the new model, not changing to values that are valid for the new scope and wondering why they don't get an error when they set it or just get a 0 measurement value.  Since I am new to this I did not know if that was a configurable item or not.

Mark

[Lea_D]

Hi MarkL,

I couldn't find any premade examples on enabling TIS. I was able to find a document that could help out a bit. This KnowledgeBase explains how to configure the PXI-515x for real-time sample rates over 1GS/s.

You mentioned trying the example Stephen pointed you to and got an error. Was it this same error? What actual example are you working off of? Alot of times it's best to start from a working example (like the ones he pointed you to) and then change what you need to gradually testing in between.