plcengineer
Member
We have a new hydraulic system that is regenerative.. I have never been exposed to a system quite like this.. We are using a 1756-HYD02 card, Balluff PWM Xducers and Bosch Rexroth Directional Prop Valves and I am seeing a strange scenario that I can't explain... When we went to startup the system, I do what I normally do with the 1756-HYD02 card settings.. I turn the P band down and then steadily increase it to get movement.. On this setup, as soon as we enabled the axis card, we started oscillating.. we measured the voltage and we were seeing .2 etc.. volts going back and forth.. So, I started using the MDO command and set the speed to .5VDC to valve.. The speed was really fast but the cylinder moved with no oscillation... Based on seeing that speed, I can see where the voltage I seen on the valve would cause oscillation...
Is there a way to get rid of that oscillation or voltage while it is just enabled? I guess on other hyd systems I have done, I never seen this because maybe that small of a voltage was nulled out... Should the card output any voltage just setting enabled or should it just stay at 0? Also, do I have any options if .5V is too fast for the application? I did see where we have directional scaling but according to the hyd guy, the ration was 1.14 and we had it at 1.. Not sure about the friction deadband settings for oscillation..
Thanks,
Is there a way to get rid of that oscillation or voltage while it is just enabled? I guess on other hyd systems I have done, I never seen this because maybe that small of a voltage was nulled out... Should the card output any voltage just setting enabled or should it just stay at 0? Also, do I have any options if .5V is too fast for the application? I did see where we have directional scaling but according to the hyd guy, the ration was 1.14 and we had it at 1.. Not sure about the friction deadband settings for oscillation..
Thanks,