Agilent E364XA IVI driver does not support measurement of 2nd channel?

[LuI]

Hi,

just downloaded the IVI driver for Agilent programmabel power supplies E364xA. It's supposed to support also the E3646A, a dual power supply. In my case there are two of 'em, connected via GPIB. I've configured 'em in MAX and have set up logical names, driver sessions and hardware assets. The two driver sessions use the hpe364xa as software module, the hpe364xa_32.dll as module path and show a whole bunch of supported devices, amoung of is also mine. I've set up two virtual channel names each for both driver sessions (4 channels over all). I can set the output voltage of both channels properly, but cannot read the voltage back. Get always the voltage level for the 2nd channel of the device. Hav
e tried measuring both or just one channel, it always returns the voltage of ch2, either two times a very narrow level or just one result.
Any idea?

BTW, this happens both in LabVIEW 7.1 and in TestStand 3.0

Greetings from Germany!
--
Uwe Frenz

[LuI]

Hi,
some more tests have lowered the severity of that bug. It appears that one can indeed read back the voltage of botch channels, but the IVI read action will always return the voltage level of the channel thats setting was most recently changed. It seems that a 'Get info'-action is not sufficient. So one needs to keep a global value of the desired voltage of both channels, just to be able to re-set it to this value in order to measure the actual value at the output?!

[gopinath]

Uwe,

I have not used this driver, and I am not sure I understand your question fully - but the problem you mention sounds like it is due to state caching. Did you try disabling state caching? (using MAX: IVI Drivers>>Driver Session>>. On the General tab, uncheck the Cache option.

[Brian_Powell]

Here are a couple of suggestions...

1) Did you try the native LabVIEW driver, too? If not, you might try downloading it from the Instrument Driver Network.

2) In the IVI driver, have you tried using the "Voltage Level" property instead of the "Measure" VI? It's not clear from the help whether this actually measures the voltage level, or can just return the last value you set, but either can probably help you. Note that you'll need to set the "Active Channel" pseudo-property first. (I.e., your property node will have four properties--"Active Channel" (for setting the first channel), then "Voltage Level", then another "Active Channel" (for the second channel) and then another "Voltage Level".

I hope this helps.

Bri
an

[Zdenek Rykala]

Hi,

the problem is that function does not set active channel. This function measure value from your last configured channel. For example: If you set volatge on channel 2, the measured value should be from this channel, if you set volatge on channel 1 before measurement, measured value should be from channel 1. 😞

I attached fixed source code and DLL. Please try it, and let me know if the problem is fixed. I don't have instrument so I cannot test it. My email is zdenek.rykala@elcom.cz . Thanks.

you should copy these files into [IVI] directory. The default path is C:\Program Files\IVI

hpe364xa_32.dll => [IVI]\bin
hpe364xa.h => [IVI]\include
hpe364xa.c => [IVI]\Drivers\hpe364xa

Zdenek