I have recently gotten my hands on a "Movemaster EX RV-M1" 5-axis robotic arm (image) manufactured by Mitsubishi in the 70's (I think). Sadly, I only have the arm and one set of cables I don't want to mess with.


I think that the robot's connectors to the control unit are IEEE-488 GPIB connectors (seen above) mainly used in older electronics and some measuring equipment nowadays. I have searched everywhere on the internet I could think of to find find fitting cables/connectors but the only thing I found are these types of cable which have the wrong amount of "pins".

Does a female 36/50 pin IEEE-488 connectors or a 36/50 pin IEEE-488 cable exist? Or could I also build them on my own? I have access to high grade CAD-Software, an industrial 3D-printer and sheet metal manufacturing methods.

I have searched for every term that came to my head on the internet and I have no idea where I should go if I wanted to find something in my proximity.

I greatly appreciate any help!

  • 2
    Sorry; we can't help you with this; questions about where to buy stuff aren't on-topic (see the help center article). Please read the tour.
    – wizzwizz4
    Jun 30 '19 at 16:56
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    I'm voting to close this question as off-topic because it's a where to buy question (beside not really pointing what kind of cable you're looking for). RC.SE is not a forum for this kind - some googling about Centronics style (Amphenol Microribbon) connectors may be more appropriate.
    – Raffzahn
    Jun 30 '19 at 16:58
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    IEEE-488 always uses 24 pins. 36-pin connectors of this type were used for Centronics printers. 50-pin connectors were used for external SCSI drives. Jun 30 '19 at 17:46
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    Are you sure it's GPIB? A quick search suggests the robot has two connectors, one RS-232 serial and one parallel. An image I saw has two Centronics connectors, a larger one (parallel?) and a smaller one. Jul 1 '19 at 6:06
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    It would be useful if you could upload a photo of the connectors on the robot arm, and the ends of the cable you currently have.
    – Kaz
    Jul 3 '19 at 8:46

Those cables you're looking at have exactly the right number of pins for GPIB; your issue is that the arm doesn't use GPIB, at least not the arm's connectors used to interface it to a computer.

The following information is taken from this copy of the manual that I found on archive.org.

  1. The 36-pin micro-ribbon connector is a standard Centronics parallel interface used for PCs and printers, and you can use any standard PC<->printer parallel cable with that port.

  2. The 25-pin D-subminiature DB-25 connector is a standard serial connector with the device acting as DTE (data terminal equipment, like a computer, as opposed to DCE like a modem) so you will need to use a "null modem" cable to connect it to your computer. It's set to 9600 bps 7 data bits even parity and 2 stop bits by default; this is set with SW2 and SW3 under the door on the unit. (I suggest always turning the unit off before changing any switch settings.) Detailed instructions on the various settings are given in Appendix 2.3 of the manual, but the most standard setting would be 9600/N/8/1 set with:

    • SW2: Switches 1-8: 1 0 1 1 0 0 0 1
    • SW3: Switch 8 on, all others off.

Either of these can be used to send commands to the arm. Serial is probably easier when using a computer, but there's also an example here of connecting and programming an Arduino for parallel communication, if you want to see how that works at a lowish level.

Comands are simple short sequences of ASCII characters. The manual suggests that sending NT, the "return to origin" command, is a good test sequence to see if communications is working. The full set of commands is described in chapter 3 of the manual.

The additional 50-pin micro-ribbon connector, if present, gives connectivity to one of four different kinds of "external I/O" cards using different protocols from the ones described below. This is more complex to use and you probably don't want to bother with it unless you're good with electronics and ready to dig into the detailed description of it in the manual.

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