plccontrols
Member
Hello,
I am working on an application that inserts a splined shaft into a 'gearbox'. The shaft is rotating slightly to allow engagement of the splines and is moved forward on a ballscrew controlled slide. It uses a Powerflex 755 drive set up for CIP motion at a reduced torque. This prevents the servo driving forward if the splines don't engage and causing damage to the shaft or the part.
I am simulating a blocked condition and I have tried using both position and velocity instructions with the same result. Using some sample code from the customer (they are very particular on code used), I either move (MAM) or jog (MAJ) the shaft to a position (currently a block of wood) at low torque (10%). Monitoring the position error and current feedback, I issue a stop (MAS), followed by a disable (MSF). It is somewhat inconsistent in that sometimes I get a smooth transition, and others get a quick reverse movement of the slide. It only retracts a few millimetres, usually, but it is quite sudden and usually causes a bang, due to the quick movement of the servo. Sometimes the axis faults, usually not.
I have monitored the torque reference, position error, and even set the current output to 0% prior to disabling the drive, but it doesn't appear to make a difference. Also, I don't seem to have access to the velocity error tolerance parameter in the PF755, like the Kinetix products do. The customer uses this parameter in conjunction with their MAJ command, which they set to a high number for this move alone (SSV), and then set back after it's completed.
Should the MSF not disable the drive completely, position error and all? How is the drive moving when the current level is set to zero? Why would it move on a disable command? What am I missing?
Thanks in advance for any assistance.
I am working on an application that inserts a splined shaft into a 'gearbox'. The shaft is rotating slightly to allow engagement of the splines and is moved forward on a ballscrew controlled slide. It uses a Powerflex 755 drive set up for CIP motion at a reduced torque. This prevents the servo driving forward if the splines don't engage and causing damage to the shaft or the part.
I am simulating a blocked condition and I have tried using both position and velocity instructions with the same result. Using some sample code from the customer (they are very particular on code used), I either move (MAM) or jog (MAJ) the shaft to a position (currently a block of wood) at low torque (10%). Monitoring the position error and current feedback, I issue a stop (MAS), followed by a disable (MSF). It is somewhat inconsistent in that sometimes I get a smooth transition, and others get a quick reverse movement of the slide. It only retracts a few millimetres, usually, but it is quite sudden and usually causes a bang, due to the quick movement of the servo. Sometimes the axis faults, usually not.
I have monitored the torque reference, position error, and even set the current output to 0% prior to disabling the drive, but it doesn't appear to make a difference. Also, I don't seem to have access to the velocity error tolerance parameter in the PF755, like the Kinetix products do. The customer uses this parameter in conjunction with their MAJ command, which they set to a high number for this move alone (SSV), and then set back after it's completed.
Should the MSF not disable the drive completely, position error and all? How is the drive moving when the current level is set to zero? Why would it move on a disable command? What am I missing?
Thanks in advance for any assistance.