Hi,
A little background before the question: The company I work for makes switches. One contact is fixed and the other is moveable on an actuator. We test the force necessary to move the actuator to close the switch to ensure it is serviceable. Currently, I am using an air cylinder to close the switch. The cylinder pushes up against an adjustable strut(for smooth slow movement), the switch we are measuring, and an LVDT all at the same time. The tooling that contacts the actuator to close the switch has a load cell connected to it so that we can monitor the force while the cylinder is pushing on the actuator. The three points we monitor are: When the actuator is first contacted(1 ounce), the point the switch closes, and the when the actuator bottoms out at 32oz of force. The processor we are using is a SLC 5/03 and a Micrologix processor as well. The Micrologix simply turns on some relays to start the test while the bulk of the data goes in the SLC. I have scaled both the LVDT and the load cell and their inputs are feeding the program as IIM with an I/O interrupt. My scan times are around 20ms. I'm using an Omega button type load cell LCKD-25 and a Trans-Tek 353 LVDT.
There is a lot that is really inefficient about this test. The pneumatics are probably not the best way to move the actuator and LVDT. The cylinder presses on an adjustable strut instead of just a fixed surface. There's probably more but I'm trying to be mostly general here. My switchpoint is about the only consistent measurement I have. The measurements should be within a certain tolerance and are not. They jump all over the place. Especially the last measurement where we capture 32oz force measurment.
If anyone has any suggestions for improving accuracy or speed(scan time), I'm all ears. I've tried most everything that is feasible that I can think of.
Thanks!
A little background before the question: The company I work for makes switches. One contact is fixed and the other is moveable on an actuator. We test the force necessary to move the actuator to close the switch to ensure it is serviceable. Currently, I am using an air cylinder to close the switch. The cylinder pushes up against an adjustable strut(for smooth slow movement), the switch we are measuring, and an LVDT all at the same time. The tooling that contacts the actuator to close the switch has a load cell connected to it so that we can monitor the force while the cylinder is pushing on the actuator. The three points we monitor are: When the actuator is first contacted(1 ounce), the point the switch closes, and the when the actuator bottoms out at 32oz of force. The processor we are using is a SLC 5/03 and a Micrologix processor as well. The Micrologix simply turns on some relays to start the test while the bulk of the data goes in the SLC. I have scaled both the LVDT and the load cell and their inputs are feeding the program as IIM with an I/O interrupt. My scan times are around 20ms. I'm using an Omega button type load cell LCKD-25 and a Trans-Tek 353 LVDT.
There is a lot that is really inefficient about this test. The pneumatics are probably not the best way to move the actuator and LVDT. The cylinder presses on an adjustable strut instead of just a fixed surface. There's probably more but I'm trying to be mostly general here. My switchpoint is about the only consistent measurement I have. The measurements should be within a certain tolerance and are not. They jump all over the place. Especially the last measurement where we capture 32oz force measurment.
If anyone has any suggestions for improving accuracy or speed(scan time), I'm all ears. I've tried most everything that is feasible that I can think of.
Thanks!