project: extending HP3478A functionality

[ysg2k6]

this is a very interesting project!

Can this hp3478-ext firmware work together with AR488? I'm thinking to install internally a well flashed arduino promini without any ttl-USB conversion circuit, simply stay inside the case, meanwhile if in case I want to do data logging, I can insert the AR488 externally and connect it to PC... my question is, is there any interference between the internal simply hp3478-ext and external connected AR488?

[Miti]

this is a very interesting project!

Can this hp3478-ext firmware work together with AR488? I'm thinking to install internally a well flashed arduino promini without any ttl-USB conversion circuit, simply stay inside the case, meanwhile if in case I want to do data logging, I can insert the AR488 externally and connect it to PC... my question is, is there any interference between the internal simply hp3478-ext and external connected AR488?

Nope, no interference from what I can see. It is completely transparent to the GPIB port. You may not need the AR488 though, the extension shows up as a COM port that emulates a Prologix GPIB adapter.

[ysg2k6]

thanks Miti. you mean use the hp3478-ext with ttl-usb circuit without AR488? my thought is to avoid drilling a hole on hp3478A case. or do you have good suggestion to do so? I think the AR488 is a generic gpib to usb adapter can be used on other instrument as well,so it is worth a try.

[Miti]

thanks Miti. you mean use the hp3478-ext with ttl-usb circuit without AR488? my thought is to avoid drilling a hole on hp3478A case. or do you have good suggestion to do so? I think the AR488 is a generic gpib to usb adapter can be used on other instrument as well,so it is worth a try.

Yes, it does involve cutting a hole in the back panel, see reply #73, but then you don’t need the AR488 anymore. You can control it, read an write the calibration constants, upgrade the software.

[kirill_ka]

Can this hp3478-ext firmware work together with AR488?

Yes and no. When the hp3478-ext is in passive state, there should be no interference (although I'm not 100% sure).
hp3478 is passive if:
- there's no SRQ interrupt
- it's not initializing
- extended function is not active
- there're no explicit serial/usb commands provoking hp3478-ext to access GPIB

[kirill_ka]

thanks Miti. you mean use the hp3478-ext with ttl-usb circuit without AR488? my thought is to avoid drilling a hole on hp3478A case. or do you have good suggestion to do so? I think the AR488 is a generic gpib to usb adapter can be used on other instrument as well,so it is worth a try.

Yes, it does involve cutting a hole in the back panel, see reply #73, but then you don’t need the AR488 anymore. You can control it, read an write the calibration constants, upgrade the software.

I second that. USB interface to the hp3478-ext is useful If you absolutely don't want to drill the case, you can still sneak a cable through one of the existing holes.

[ysg2k6]

Thanks kirill, I played the software HP_3478A_Software_AR488_Arduino_GPIB and HP3478A.exe, they are also interesting but I'd rather use the pure bench meter function, so I made decision not to make an external serial connection. the HP3478-ext I like most, and also I think the most useful function, is conductivity and diode, it is very helpful when doing some repair work.

so I made a simplified circuit and a tiny PCB, it works like a charm! I BTW changed the 4 capacitors as well, now it may work for me for anther decades :-)

[kirill_ka]

Thanks for the pictures! Very nice and clean installation.
It's funny that you also find the diode function useful. It's just 3k Ohms mode with the units displayed as V. HP3478A has precise and round current source for Ohms measurement so the reading also can be interpreted as a voltage drop. I decided to add the "diode" as a separate function so I don't have to remember the Ohms range I need to select.

[ysg2k6]

Thanks for the pictures! Very nice and clean installation.
It's funny that you also find the diode function useful. It's just 3k Ohms mode with the units displayed as V. HP3478A has precise and round current source for Ohms measurement so the reading also can be interpreted as a voltage drop. I decided to add the "diode" as a separate function so I don't have to remember the Ohms range I need to select.

Kirill, I'm interested in how you do this "Ohms interpreted as voltage drop". I have a linear programmable power supply with GPIB interface, what I want to do is to replace the transformer and diode bridge by an adjustable switching power supply, make the switching power output always 5V higher than the programmed output. by this way I can extend the max current from 1A to 5A, now I need to interpret 1A shown on PSU as 5A ... can I do the same as you did for HP3478_ext diode function? I'm not good at C coding, but if you can explain the way in detail, I believe I can try to make the code using Arduino.

[kirill_ka]

Kirill, I'm interested in how you do this "Ohms interpreted as voltage drop". I have a linear programmable power supply with GPIB interface, what I want to do is to replace the transformer and diode bridge by an adjustable switching power supply, make the switching power output always 5V higher than the programmed output. by this way I can extend the max current from 1A to 5A, now I need to interpret 1A shown on PSU as 5A ... can I do the same as you did for HP3478_ext diode function? I'm not good at C coding, but if you can explain the way in detail, I believe I can try to make the code using Arduino.

Sorry, I don't understand what are you trying to do.
Note that the GPIB is just a bus. You need to check the command set of the particular instrument to see if your idea can be implemented.

[ysg2k6]

Thanks Kirill, it works now but I see those issues as well and my laptop is I7  .
If I set it to fast, beside lagging behind the instrument, I see something that looks like burst reading. It updates fast a number of times and then it freezes for half a second or so. This happens with AR488 as well.

may I invite you and @kirill_ka to test the modified HP3478A PC software? the full credit is owned by the original author(https://github.com/Niravk1997/HP-3478A-Software)

unzip the attached .exe file and replace the one on your disk.

[selevo]

Hi all!
Can anyone tell how to use tcl? I didn't find any documentation. My multimeter does not have a display (cracked) . I want to read readings using a computer and this adapter (hp3478aext)
https://github.com/KIrill-ka/hp3478ext/tree/master/tcl

[kirill_ka]

Hi Selevo,
Are you targeting some automated measurements or just want to see the readings?

[yo0]

Hello, will be implemented the to do list?

especially the dBm function

/*
 TODO list

 - Display 0 with O?
 - Implement unbuffered binary write TUD using escape-sequence as stop
 - Implement unbuffered binary read TUD using escape-sequence as stop
 - Save & restore "ext" functions using presets.
 - Add dBm measurements in ACV.
 */

/*


Best regards

Pio

[kirill_ka]

Hello, will be implemented the to do list?

especially the dBm function

Hi,
Do you think the world is ready for it?
Ok, I'd add it by the end of 2023

- Save & restore "ext" functions using presets.

That was done already by the way. I forgot to remove it from the list.

[yo0]

Hello, will be implemented the to do list?

especially the dBm function

Hi,
Do you think the world is ready for it?
Ok, I'd add it by the end of 2023

- Save & restore "ext" functions using presets.

That was done already by the way. I forgot to remove it from the list.

yes we are ready!!

thank you very much!!


best regards


Pio

[selevo]

Only for read LCD information
I’ve been wanting to write something in tcl/TK for a long time, and then I came across an example that was just related to my problem. Although on the other hand it may not be very correct to install another interpreter one more language and do it another bike. )) While Windows has built-in tools for working with scripting languages.

Hi Selevo,
Are you targeting some automated measurements or just want to see the readings?

[kirill_ka]

Writing GUI in Tcl/Tk is a pure fun The Tcl/Tk runtime is very compact if you get just an interpreter. You may even try androwish as it seems to have serial support. I think of adding some basic Tk GUI sample so to have at least something to start with. Selevo, feel free to PM me if you have questions about using Tcl with hp3478ext.

[kirill_ka]

Here's a preliminary version of dBm function.
The reference can only be set with the console command.
E.g. Odbm_ref50w sets the reference to 50 Ohm.
Switch to ACV, then three times press SRQ then LOCAL to enter.

Pio, do we want a way to show/select the reference prior to entering the dBm mode? What do you think?

[yo0]

I think it is a very good idea, thank your very much for you valuable effort and talent, and happy new year to all!