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Intelligent Actuator Inc (IAI) Actuator Q&A Print E-mail
Written by Automation Engineering Staff   
Thursday, 16 December 2010 08:40

AS Actuator FAQ

Q: There is a "clacking" noise originating from the motor end of the actuator. We've also noticed that our points have a lot of looseness in them, up to 1 or 2 DSmm.

A: Generally, the cause of the noise is either a loose or worn motor coupling. The internals of the coupling are plastic and designed to wear out over time. This probably needs to be replaced. This would also cause your positioning problems.

ASQ: Once we power up the machine in the morning, the unit runs fine for a while, but the positions start to "drift" and eventually the controller faults out. It appears to be getting worse.

A: When positions start to drift by the same amount and get progressively worse, the motor brushes are usually the culprit. Since these motors are DC motors, motor brushes are present and need to be replaced. Check to see if the motor you are using has replaceable motor brushes. If not, you may need a new motor.

Q: Every once in a while, the machine gets jammed so we have to E-stop the system. Once we power back up and re-home, all of our points are off by a certain amount. We cycle power again, and it's fine.

A: The parameters are set at a certain home current level value that must be reached for home to complete. Once this limit is reached, the motor reverses direction until it reaches a "z-pulse" on the encoder wheel. It is possible that the motor is sensing a different z-pulse every once in a while and throwing off your positions. Simply raise the home current limit, or loosen the motor coupling, rotate the motor shaft, and then tighten back down.

Q: We would like to upgrade the system to the newer, more powerful 32-bit SEL controller. Is there a DC equivalent SuperSEL Controller?

A: Yes. The E/G Series is available with DC drivers instead of AC drivers.

DS Actuator FAQ

Q: Can the DS be configured in a three-axis setup?

A: No. In a typical 3 axis configuration (X,Y,Z) the frame of the slider type cannot handle the moment load of two more axes attached to it.

Q: What about a DS with a limit switch, is it possible? How about a creep sensor?

A: There is no allocation for a limit switch or creep sensor on the DS controller or frame. An external limit switch could be tied into the DS inputs and a program written to monitor these inputs, but homing off the limit switch or performing a high-speed home (creep) is not possible.

Q: Instead of using two types of grease for preventative maintenance on the DS series, can we use the same lithium-based #2 grease on both the ballscrew and linear guide rails?

A: Yes. As long as the grease is lithium #2, the same can be applied to the ballscrew and linear guide rails.

Q: After adding our tooling and payload, the DS wants to home in the middle of the stroke, how can we fix this?

A: The DS home parameters are usually configured for near rated payload. In the case where the DS is homing before reaching the hard stop, the "Home Current" parameter is usually the culprit. Try to increase this by 10 and reset the controller. This extra current should be enough to get past the problem.

Q: 6 months after installation, we decided to reconfigure the machine. The DS Arm Type is being used and we followed the instruction on page 50 on how to change the motor position. All of our point data is off.

A: Since the Arm Type uses a belt/pulley coupling method between the motor and ballscrew, any movement of the pulley independent of the belt changes the home position. Either re-teach your points or adjust the Home Offset parameter to compensate for the error.


Q: How is it the IS/ISD/ISD-CR is so short overall? Isn't the motor coupled to the ballscrew, and if so, when should I replace the coupler/brushes/motor?

A: The "IS" in IS/ISD/ISD-CR stands for "Integrated Series" meaning that the ballscrew and motor are integrated. There is no coupling for the motor because the motor windings fit around the end of the ballscrew which has a magnet attached (keyed). In essence, the ballscrew with the magnet, is the rotor. There are no brushes to replace as it is an AC brushless servo.

Q: Is there any way to home the IS faster than the standard 10 mm/sec velocity?

A: At the time the system was ordered, this option should have been specified. If you already have a limit switch option, the change to the creep option is simple and can be done in the field. If you do not have the limit switch option, you probably don't have the limit switch connector on the controller, so this would have to be added in addition to adding the limit switch to the actuator itself.

Q: Instead of using two types of grease for preventative maintenance on the IS series, can we use the same lithium-based #2 grease on both the ballscrew and linear guide rails?

A: Yes. As long as the grease is lithium #2, the same can be applied to the ballscrew and linear guide rails. Make sure that you have the IS/ISD series and not the ISD-CR. The CR series uses a fluorine-based grease that does not mix well with lithium-based grease.

Q: Our process has changed and we now require a brake on one of the axes. Is the brake something that can be added in the field?

A: Yes. Adding on a brake module requires changing the non-motor endcap to the brake endcap and then adding the actual brake. Most controllers already come with the brake connector installed, but if the controller does not have the brake connector installed, IAI would have to add it. In addition to these two items, you would also need a brake box and new motor/encoder cables.

Q: If I want to change the distance the slide rotates off of the hard stop, can I just rotate the encoder wheel?

A: No. The poles of the motor are lined up with the z-phase slots on the encoder wheel for commutation and homing purposes. If the encoder wheel is rotated, more likely than not, the poles of the motor will no longer be aligned with the encoder wheel. If the wheel is out of alignment and the attempt is made to home or turn the servo on, the slider will fault out the controller as "A5" as the pole is not sensed.

Robo Cylinder Actuator FAQ

Q: We have multiple controllers linked together. The second and third controllers are not being sensed using the teach pendant or the software. Has the teach port failed?

A: Not likely. Check the addressing on dip switches 1-4 to make sure that two of the controllers aren't assigned the same address. For addressing, check out page 12 in the manual

Q: We bought the rod type for the push capabilities, but how does it work?

A: Pages 25-28 in the Robo Cylinder RCP Controller Operating Manual describe how the push mode operates. To activate the push mode, the "Push %" column in the point table needs to have a value in it (based on the graphs on p26-27). Where the push begins and ends is based on what value you have in the Push column, the Range column and the Position Data column. Note that the Push Feature should be used with the RCP Series, as opposed to the RCS.
Q: What kind of side load can the rod type handle?

A: Due to the design of the regular rod type, it cannot handle any side load whatsoever. If the guide option is purchased with the rod type, then side load is possible.

Q: Can the Robo Cylinder units be configured in a three-axis setup?

A: No. In a typical 3 axis configuration (X,Y,Z) the frame of the slider type cannot handle the moment load of two more axes attached to it.


Q: We powered down our backup IH-SCARA robot for about 6 months. When we powered back up, the IH-SCARA's encoder feedback was extremely wrong.

A: There is a lithium battery backup of the IH-SCARA's absolute encoders. This battery only goes into effect when the unit is powered down. Unfortunately, this battery is not rechargeable and probably needs to be replaced. In addition to this, the IH-SCARA needs to be re-homed as it no longer has updated encoder data.

Q: We've got a few other machines running on the same 220VAC line as the IH-SCARA. When we're in full production sometimes the IH-SCARA will fault out 'A7' on all 4 axes and the z-axis will drop.

A: We recommend that the IH-SCARA controller is powered by a dedicated constant-voltage transformer. If one is not available, please use a dedicated 220VAC line that runs at a voltage level of 200/220VAC +/- 10%. The A7 and z-drop is due to a quick dip in voltage level forcing the controller to think the motors are still on, even though the dip cut power.

Q: When we open our door guards, the IH-SCARA controller goes into E-stop. We've got medium-tension air tubing wrapped around the Z-axis, and sometimes the theta location will be "off" after releasing E-stop.

A: If any of the IH-SCARA axes are moved during the controller boot-up sequence (after power-up, e-stop or reset) before "rd" is on the display (ready), the encoder data will be inaccurate. There is no fix for this at the moment.

Q: What's the difference between wiring for the NPN I/O card and PNP IO card?

A: The main difference is that the power connection for Power (+24V) and Common (0V) are switched. On the NPN I/O card, the power connection is on pin 1A (Brown) and the common is on 25B (Black). The PNP card is the exact opposite from the NPN card.

Q: Our system has grown in size and we're considering the option of a vision system. We didn't purchase the original SCARA system with the 2ch RS232c option installed. Is this something that we can install ourselves?

A: Expansion I/O and 2ch RS232 cards can be added in the field. Anything above and beyond this, however, would require an IA Engineer to modify the controller in-house or on-site.

About IAI

Intelligent Actuator Inc (IAI) is a world leader in the design and manufacture of off-the-shelf single and multi axis servo positioning systems and SCARA robots. IAI provides a broad range of Intelligent Actuator brand actuators ranging in stroke from 50 millimeters to 3 meters in length with speeds up to 1,500 mm per second and payloads up to 80 kg. New RoboCylinder model actuators offer closed loop performance in the price range of pneumatics. IAI also offers class 10 cleanroom actuators and robots and ESD-rated actuators for specialty applications. Ease of programming and superior design of these off-the-shelf systems allows for extremely fast implementation and system start-up. Increase your throughput and productivity with IAI servo actuators! Intelligent Actuator Inc IAI is an industry leader in "Green" Automation. Automation Controls is proud to be IAI's largest hi-tech solution provider in the United States.