text: <s>[INST] Using MAJ instruction when a MAG is already active Hi everyone, I'm actually trying to torubleshoot a Tension control system created for an OEM and the way it actually works is gearing the axis with a virtual master and then after passing a defined speed they are enabling the tension control and beginning using MAJ instruction with a speed value calculated using a PIDE instruction using like input the tension provided by a load cell and a defined tension Setpoint I know that we can superimpose a MAJ instruction in an active MAG but I need to know how it is going to work?. What I'm actually seeing is the axis running at aprox 5000 degrees/Sec (close to the Virtual Master speed * gear ratio) and values in the speed of the MAJ instruction oscillating between -15 and 15 (completely far from the actual velocity value around 5000 degrees/sec). How this MAJ instruction is actually working?. Thanks in advance for all your comments adn if you think more info or clarification is required please let me know. [/INST] Hello Munoz this is a common way of doing tension control system, the feedback may vary a lot and features as well. but most of the time it's the use of the move compensation or/and outer loop control equation, that could be more or less complex depending on the application requirement in term of dynamic and accuracy of the control. Some use directly the gearing factor to track the setpoint, of some like in your case use the Superimposed movement. So in your case the JOG (MAJ) is used as a superimposed movement on top of the actual movement (MAG). This is possible thanks to the great Logix/Kinetix motion control system implementation. Internally the movement are all incremental and they can be summed before being sent to the output command for the Servo Drive this the magic part. see bellow diagram So if you have a MAG running on your axis you are still able to apply another movement like a jog, and the sum of the 2 movements are sent to the axis drive. This is possible also because of the incremental internal treatment. So this is very simple in fact... nothing special a, a MAJ can be superimposed to any actual motion movement running on the actual axis. the end result will be the sum of those movement. so your axis run a 5000 deg/sec and each time your algorithm requests it, a superimposed Jog of + or - 15 deg/s will be applied. Depending on the code this could be executed once or multiple time in the row (that will impact the dynamic and the compensation capability). But that needs to be controlled in a nice way to avoid any overshoot or pumping effect that can conduct to uncontrolled motion, since you are using an outer loop control system. Does that help to understand. so, your velocity command will vary with increments of 15deg/s (pos or Neg) to make the load cell matching your load setpoint. I hope that helps regards \\n </s>