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kratmel

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Posts posted by kratmel

  1. Unfortunately, you did not say anything about the application itself, for which the servo motor is used.

    There are probably safety requirements and standards for this application. Usually, the standards are based on the current state of technology development. Special safety inputs for converters have appeared quite recently and have accordingly been added to existing standards as additions.

    On the one hand, you want to stop the engine quickly, and on the other hand, you say that the fastest way to do this is to turn off the power.

    So I think only following the safety standard is correct. If it involves turning off the power supply of the power unit, then it should be done that way. The frequency of turning on and off the power will not be high anyway.

  2. Paying attention to servo motors, we must take into account that they are usually used in positioning mode.  This mode involves setting the final coordinate in advance.

    That is, the activation of the safety system must change the task of the servo drive so that it stops as soon as possible.

    Disconnecting the motor from the servo drive via safety relay is generally unacceptable. This will probably cause the driver to crash.

    Disconnecting power from the servo driver will not provide the desired instant stop.

    Therefore, after studying manual for the Unitronics servo driver, I came to the conclusion that the most effective in your case is the use of discrete input signals P-OT and N-OT. This two signal can be selected via Parameters (p.64-65). This two signal can be used as a command for an unconditional stop. Using the zero clamp settings to work out the P-OT and N-OT mode, you can create safe application.

    Additionally, you can add  Unitronics motor with a brake and create a configuration for guaranteed holding of the motor in the stop position.

    Safety relay has two ot more contact - that can be used for generate P-OT and N-OT signal simultaneously.

    For additional information please contat support@unitronics.com.

     

    P.S. I must draw your attention to the need for careful study of legal norms - national standards that regulate the operation of the safety system for the equipment where the operation of the servo drive is planned. I have studied these documents for many types of equipment, so all your steps and schematics should follow these requirements.

  3. 4 hours ago, jesuscardenas said:

    Here I would have a problem since the transmission chain is commanded by a variator of frequency

    I think you have little choice. Unfortunately, the equipment you have is not up to the task as stated above by many contributors.

    Therefore, you need to add one more delta servo to the circuit and apply the proposed application. Or look for a set of equipment from well-known manufacturers with a ready-made application - and this can cost a lot of money.

  4. In fact, this task is an example similar to the rotary knife or high speed labeling. I doubt you will be able to achieve the accuracy you want with used hardware and software. In such systems, not only speed PID is needed, but also position PID.

    In my opinion, you should consider mechanical synchronization between the large print shaft and the chain conveyor in your system. Accordingly, their speeds were the same, and the stop bar on the chain exactly periodically coincided with the start of printing on the cylinder.

    By the way, what type of servo driver is used for the large shaft?

    p.s. Please read some info in pdfs...

     

    PTiAN-03_Rotary Knife with the PTi210.pdf PTiAN-04_High Speed Labeling with the PTi210.pdf a-guide-to-motion-control-technology-systems-programming-iss2x-0704-0007-02x.pdf

  5. The best way is to use the high-speed counter built into the PLC (I0 or I2) and assign it a to large integer number (ML or DW) in Hardware Config - High speed counter  to accumulate an energy value with  0.1 kW increments. Further, this number can simply be displayed on the screen by moving the comma one unit to the left in the display.

    Then no floating point calculations are needed.

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