Motor control advice,
I've been programming a transfer system that transfers parts from one station to the next. The FWD and REV travel is controlled by a motor.
The problem I'm having is that sometimes a part will fall off the transfer and the transfer will smash or wedge the part against something as its transferring and causes damage. There are other situations that occur that also causes the transfer to smash a part into something. I know this is not a lot of information, but I have ruled out that I cannot do any more programming or sensor installations to keep this from happening.
This motor is controlled by a Mitsubishi E500 Frequency drive. There is a setting in the parameters that allows me to set up the output current monitor. This setting is for allowable output current from the VFD and how much time it can run above the set current before the VFD will shut down. I thought great, I can set this up so if the transfer runs into something the motor will draw more current, thus shutting down the VFD before any major damage. BTW, the transfer runs at a low speed. I thought I could set the allowable output current from the VFD just a little above what the motor was running at in normal operation. The problem is that when the transfer goes back to home position it hits a slow down limit switch, which slows down the transfer, so it doesn't overrun the home position limit switch. When it hits the slow down LS the VFD outputs a lower frequency. The motor at this point draws almost double the normal operating speed current. This is obviously a problem in the way I sat up the parameter. The VFD shuts down when it hits the slow down LS.
Is there something out there that will allow me to monitor the motor current at predetermined times of your choice? Basically in my situation, I don't really need to monitor the motor at the point where it’s slowing down to reach home. This is a short distance and I don't think I need to worry about this point in the transfer process. What I do need to monitor is the danger areas of the transfer process. I'm looking for something that I can give an output from the PLC or through a relay to tell the monitoring device when I want it to monitor the motor current draw. Like I said this transfer moves slow, so I think I can stop it before something gets broke. This equipment is brand new and I already have had to replace six $700.00 SMC cylinders. Not to mention the countless hours of programming to help combat this problem.
I don't have the motor specs with me, but if this is something someone is going to need let me know.
Thanks in advance,
Tim
I've been programming a transfer system that transfers parts from one station to the next. The FWD and REV travel is controlled by a motor.
The problem I'm having is that sometimes a part will fall off the transfer and the transfer will smash or wedge the part against something as its transferring and causes damage. There are other situations that occur that also causes the transfer to smash a part into something. I know this is not a lot of information, but I have ruled out that I cannot do any more programming or sensor installations to keep this from happening.
This motor is controlled by a Mitsubishi E500 Frequency drive. There is a setting in the parameters that allows me to set up the output current monitor. This setting is for allowable output current from the VFD and how much time it can run above the set current before the VFD will shut down. I thought great, I can set this up so if the transfer runs into something the motor will draw more current, thus shutting down the VFD before any major damage. BTW, the transfer runs at a low speed. I thought I could set the allowable output current from the VFD just a little above what the motor was running at in normal operation. The problem is that when the transfer goes back to home position it hits a slow down limit switch, which slows down the transfer, so it doesn't overrun the home position limit switch. When it hits the slow down LS the VFD outputs a lower frequency. The motor at this point draws almost double the normal operating speed current. This is obviously a problem in the way I sat up the parameter. The VFD shuts down when it hits the slow down LS.
Is there something out there that will allow me to monitor the motor current at predetermined times of your choice? Basically in my situation, I don't really need to monitor the motor at the point where it’s slowing down to reach home. This is a short distance and I don't think I need to worry about this point in the transfer process. What I do need to monitor is the danger areas of the transfer process. I'm looking for something that I can give an output from the PLC or through a relay to tell the monitoring device when I want it to monitor the motor current draw. Like I said this transfer moves slow, so I think I can stop it before something gets broke. This equipment is brand new and I already have had to replace six $700.00 SMC cylinders. Not to mention the countless hours of programming to help combat this problem.
I don't have the motor specs with me, but if this is something someone is going to need let me know.
Thanks in advance,
Tim