ScannerMax compact506 + Medialas microamp driver

Discussion in 'ScannerMAX' started by Gianluk16, Nov 19, 2015.

  1. Gianluk16

    Gianluk16 New Member

    Hi everyone,

    I'm new in using this forum and on working with the galvos, I'm doing a project where I'm using the compact 506 with the microamp driver.

    In attachment there is the datasheet that medialas provided me for the drivers, with both the pinout for the output and input of the drivers.

    I modified the driver as specified on the galvos page and I'm using two power source, which can generate +-30V, from medialas, to source the two driver boards.
    I connected the +-30V and ground on the boards and as a test, before I connected the galvos to the driver board, I measured the voltage drop between the motor+ and motor- output of the driver board, so the input pin of the galvos. I measured a value of 30V, without any input. Even if I try to connect an input differential signal to the driver board the voltage drop between the two output pins remain 30V.

    So even if they are differential signals, isn't it too much 30V between the input pins of the galvos?
    How do the galvos work? Do they need always a voltage even if they are at the position 0?
     

    Attached Files:

  2. Pangolin

    Pangolin Staff Member

    If you want, you could sent it to Pangolin for examination. We can find out what is happening. We suspect that the problem is the cable that goes between the amp and the scanners.
     
  3. Gianluk16

    Gianluk16 New Member

    Thanks for the answer, but I haven't connected the galvos with the boards yet, how can be the cable the problem?
    I have done further measurements and on the motor+ pin, where I expected a positive voltage, I have -30V referred to the motor- and pd shield which both seem a ground, how do the boards work?
    Do they convert an input voltage signal to an output current signal to control the galvos?
    Or is there something wrong in my boards output?
     
  4. Pangolin

    Pangolin Staff Member

    How indeed...

    The galvos have a position sensor. In order for the position sensor to work, current must be supplied to an LED inside. Normally around 8mA is used to the LED, but it could be as much as 20 or even 30...

    Once the LED is lighting, the photodiodes will produce photocurrent in proportion to the position. The current is on the order of 10 microamps per degree (or so).

    The motor is a coil having a resistance somewhere between 2 ohms and 3 ohms.

    If the driver is outputting voltage but the motor is not moving, then MOST LIKELY you have connected the motor leads from the amplifier to the position sensor instead. (Users do this from time to time...) When this happens, the position sensor will be blown, because the photodiode can not withstand 30 volts from the coil driver...

    For most clients our scanners simply work, and that is all. You just connect it and it works. If it doesn't work, then often the problem is one of understanding, or cabling, or driver, or something else.

    Within a relatively short time we will be delivering our own servo driver for the Compact 506 and then I am sure the few problems people have from time to time will cease.

    Best regards,

    William Benner
     
  5. zerowaitstate

    zerowaitstate Active Member

    I figure there are a lot of compact 506 scanners out in the wild by now, and it makes sense to try and optimize cues to look their best ( nice solid beams etc with out flicker) to that end.

    What is the default speed / angle configuration would you recommend when setting up beyond using a projector using Compact 506 scan sets . i understand they are load of variables to consider im using a clubmax3000 (one assumes kvant has a good relationship with you guys and their drivers are optimized to run the 506 as well as possible)

    knowing the above would make it easier to match point counts to suit.

    any advice appreciated
     

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