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GPIB setup on Linux

• 3 Dec 2021 Revised by Kazuyuki Takeda
• 14 Mar 2019 Revised by Kazuyuki Takeda
• 12 Oct 2018 Revised by Kazuyuki Takeda
• 21 May 2018 Written by Kazuyuki Takeda

Introduction

We want to make remote control over the power supply for our cryogen-free superconducting magnet (SMS80C, Cryogenics) on the console software of Opencore NMR 2. I have attempted to program on Windows for a while, but never succeeded, and gave up. Now I decided to program on Linux.

Our GPIB

• Measurement computing
• USB-488
• Default primary address: 4

Driver compilation (Cent OS)

linux-gpib-4.1.0

• linux-gpib-4.1.0 was downloaded from http://linux-gpib.sourceforge.net and extracted in an arbitrary working directory.
• ./configure
• make

linux-gpib-4.2.0

• If you download the latest (at the time of writing, Mar 2019) version (linux-gpib-4.2.0) and try to compile in the same way as the above example, you may get an error implicit declaration of function ‘of_find_node_by_path’, and the compilation may stop.
• A remedy is suggested here.
• In short, you need to open drivers/gpib/Makefile with a text editor and comment out the line obj-y += fmh_gpib/
• Then, compilation should work.

Installation and setup

• sudo make install
• And the kernel driver module is ni_usb_gpib.ko, and the board type, to be described in /etc/gpib.conf, is ni_usb_b.
• Driver file ni_usb_gpib.ko has been created upon successful compilation. To install, I went into the directory that contains it and ran sudo modprobe ni_usb_gpib. To verify the driver has really been installed, I checked with lsmod | grep gpib.
• Next, we needed to edit /etc/gpib.conf as follows:

interface {
        minor = 0       /* board index, minor = 0 uses /dev/gpib0, minor = 1 uses /dev/gpib1, etc. */
        board_type = "ni_usb_b" /* type of interface board being used */
        name = "current"        /* optional name, allows you to get a board descriptor using ibfind() */
        pad = 0 /* primary address of interface             */
        sad = 4 /* secondary address of interface           */
        timeout = T10s  /* timeout for commands */
        eos = 0xda      /* EOS Byte, 0xa is newline and 0xd is carriage return */
        set-reos = yes  /* Terminate read if EOS */
        set-bin = no    /* Compare EOS 8-bit */
        set-xeos = no   /* Assert EOI whenever EOS byte is sent */
        set-eot = no    /* Assert EOI with last byte on writes */
        master = yes    /* interface board is system controller */
}

• name = current should be arbitrary (optionally used for ibfind function).
• pad=0 and sad=4 were necessary, with the dip-switched primary address on the current controller being 4. And in the program coding, it was necessary to set pad to be 4. My guess is: the primary address to be set on the operating system is relevant to the GPIB-USB adapter (in our case, we are using a single adapter, so that the address is the youngest, i.e., zero), whereas on the software we are supposed to connect to the device (in our case, the magnet power supply whose address is set on the dip switch on the pear panel to be 4).
• After saving the gpib.conf file, I ran sudo gpib_config, which makes setup according to the above gpib.conf file.
• Found in linux-gpib-4.1.0/lib/gpib_config.

Without sudo…

Go to /dev, and sudo chmod a+rw ./gpib0.

TODO

To realize plug and play, udev needs to be configured to (i) change the mode of /dev/gpib0 to 0666, and (ii) implement gpib_config. I will try to work it out and update this page (12 Oct 2018).

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