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HP3478A HPIB

 

Hi Everyone,?

Not sure if I am being stupid here, I have been writing my own VB.net code so that I can control some of my bench via gpib. One of the instruments i have is a 3478A.?

I can control the instrument with some Commands, setting measurement functions and Ranges etc, however when I want to send a "TRIGGER" command, it instead returns the "Error" byte which is denoted by an "E" command. Likewise if I try to send the "CLEAR" command as shown in the user manual, it attempts to enter the Calibration mode, typically denoted by a C command.?

Yet using Keysight connection expert, if I click on the "reset device" option in the IO window, the IO monitor doesn't show which commands are sent, but the instrument essentially power cycles and performs self test.?

So I am missing something, has anyone programmed one of these via the HPIB bus? Also, I have read online that it is possible to read back the Calibration table via hpib, but neither the user or service manuals say anything about reading the data back, does anyone know anything else?

Thanks,
Taylor
 

Taylor,
Just to be clear, are you sending something like "T3", not literally "TRIGGER"??
(I think the valid trigger commands are T1, T2, T3, T4, and T5.)
--John Gord


On Sat, May 18, 2024 at 03:34 PM, Taylor_d2010 wrote:
Hi Everyone,?

Not sure if I am being stupid here, I have been writing my own VB.net code so that I can control some of my bench via gpib. One of the instruments i have is a 3478A.?

I can control the instrument with some Commands, setting measurement functions and Ranges etc, however when I want to send a "TRIGGER" command, it instead returns the "Error" byte which is denoted by an "E" command. Likewise if I try to send the "CLEAR" command as shown in the user manual, it attempts to enter the Calibration mode, typically denoted by a C command.?

Yet using Keysight connection expert, if I click on the "reset device" option in the IO window, the IO monitor doesn't show which commands are sent, but the instrument essentially power cycles and performs self test.?

So I am missing something, has anyone programmed one of these via the HPIB bus? Also, I have read online that it is possible to read back the Calibration table via hpib, but neither the user or service manuals say anything about reading the data back, does anyone know anything else?

Thanks,
Taylor
 

Greetings Taylor,

While I do not have this meter, I did take some time to read the programming section owner's manual. I do not see anything in the command table that allows you to "clear" the instrument with typical HP-IB commands (ie *RST, RE or IN). According to the user's manual "C" is reserved for calibrating. However, it appears that the command "H0" can be used to return the instrument to a power on condition. The only other clear function I see in the manual is done on the controller side that can be used to clear the HP-IB interface. I may have to pick up one of these meters just to test my assumptions.

Best Regards,

Craig Petersen
 

The 3478A is an old device with limited GPIB commands.

To trigger it you need to send a GPIB Trigger (aka, Group Execute
Trigger). ?It's a bus control sequence, not a text command.

Likewise, a full reset is done via a GPIB Clear sequence (aka, Device
Clear).

The trigger command "Tn" sets a particular trigger mode from 1 to 5,
but does not itself cause a trigger. ?And "Hn" is selecting one of
eight presets, 0 to 7, which are described in the manual.

You could put it the same mode as a reset by sending "F1RAN5T1Z1D1".
Note that it only accepts upper case.

If you just perform a read from the 3478A with no command, it will
return the reading after the next trigger. ?So, if you leave it on
internal trigger mode (T1) and do a read, you'll always get the latest
reading.

-mark
 

Thanks for the quick replies all, what i had hoped to do is to recreate what the Keysight "Interactive IO" does where sending a command resets the instrument to Power on conditions i.e. forcing a Self Test etc.

*RST, RE, IN etc dont seem to be doing anything at all. According to the "advanced programming" sections of both User and Service manuals (D/L direct from Keysight this week) it says about Local, Remote, Local Lockout etc but doesnt mention any mnemonics etc, just the exact string.

I have read through the HPIB tutorial in the files section here which says about the mnemonics like LLO, REM, GET etc but trying them this morning they have not worked either.

I am using the Keysight IVI.VISA resources in Visual Studio, i essentially build a string and then write that to the USB>GPIB adapter (Keysight 82357A). doing this so far i have written my VB.net form so that i can select different functions etc and build up an entire string, such as F1RAN5T1Z1D1 and send it to the 3478A. Using Keysight IO monitor, you can "sniff" the GPIB bus and doing this i have verified that it is sending the string i have created, e.g F1RAN5T1Z1D1/n .This example would set it as DCV, Auto Range, 5 digits, Internal Trigger, Auto Zero "ON" and D1 returns it to the normal display. So this part all works, and i can switch between the measurement functions and ranges with no issue.? I can read back the status bytes too, reading the error register etc.

However i still cannot get the "generic" HPIB commands to actually work.

With my instruments which only have RS-232. I always obtain remote control of the instrument, and then immediately do a reset/self test command if possible, to check the instrument is working, initialises ok, and then carry on with any controls afterwards. So i am hoping to do the same with my GPIB devices. I thought i would start with my 3478A as its one of the more simpler devices. I also have a Keithley 213 which can only be triggered by GPIB to enable its output so that was going to be my next step after this as the 3478A is more "visible" when you have correct control over the instrument.
 

Hello Taylor.

This issue is similar to another instrument that I use, an HP 3437A System Voltmeter. It only has 8 commands and generally ignores "generic" HPIB commands like *IDN?, *RST, etc, in this case the instrument just simply returns the measurement being displayed. I love this meter because it is capable of taking 5600 measurements per second. However, my typical sample rate is generally limited to about 350 samples per second due to slower instruments sharing the bus. But just like your HP 3478A these generic HPIB commands are either ignored or cause undesired instrument behavior.


Best Regards,

Craig Petersen.
 

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The link above takes you to the HP 3478A operation manual. Pages 35-62 are the remote programming functions and protocol and lists all of the remote programming commands.?
This instrument is moderately early in the development of HPIB programming so the generic HPIB commands from later developments in the HPIB languages are not recognized because they are not in the 3478A command set in its PROM.
If you want more modern HPIB programming then I would suggest the 34401A DMM (6.5 digits) or later, a better, more capable DMM than the 3478A (5.5 digits).
Don Bitters

 

....and i suggest that you should be using a modern object oriented lingo, like Python3, not Vb. (Pyvisa for GPIB).

 

Whatever works and you are comfortable with. For me I just need to get the data into Excel for processing and there VBA fills the need.

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