Torque controlled buffer wheels

Epic designs and builds motion controls to control the torque of an AC motor driving buffer wheels using a servo controlled slide.

The customer wanted a way to compensate for the wear of the buffer wheels over time and have a constant buffing force. Buffer force is proportional to the rotational torque of the buffer wheels. The buffer torque feedback is fed into the Siemens 1214 PLC torque regulator. The buffer wheels are mounted on a slide which moves in and out to apply the correct force on the part held by the robot. If the buffer wheel torque is less than set point, the servo motor controlled slide moves in, if more than set point the slide moves away from part. As the buffer wheel wears down, the slide will compensate to keep same force on part. As the robot turns the part and the distance changes, the slide will keep constant force.

Buffer wheel force control video

Epic designs and builds controls to apply RTV on lithium battery POD.

Epic Engineering, LLC designs and builds a controls system to apply RTV sealant to a lithium battery POD. The manufacturer previously manually applied the RTV sealant which made the process slow and inconsistent. Epic used Intelligent Actuator Inc. Robo Cylinders to move the RTV head to the perfect profile path. This robot saved the manufacturer a lot of time, money, and much less waste. Please see video. RTV Sealant Robot

PLC power monitor helps manufacturer save $70,000 per year.

Epic Engineering designs a PLC to automatically shut down parts of a customers process when power usage goes above a certain threshold.

A local brick and block manufacturer uses a lot of electric energy to produce bricks and concrete blocks. The manufacturer used to be on a A19 plan with PG&E where the demand was calculated by Kilowatts used and penalties for going into peak usage. They found that they rarely went over 500KW throughout the day. It was determined that if the process could be kept below the 500kw demand throughout the day, they would be able to move to a less expensive rate plan, A6.

Epic used a PLC connected to the P,G,&E power meter to accumulate kilowatt hours used. P,G,&E uses a 15 minute average to calculate real time demand so we replicated that average in the PLC. A warning and fault threshold are operator adjustable on one of the HMI touchscreen screens. A yellow light will flash when the 15 minute KWH exceeds the warning threshold. If the 15 minute average exceeds the fault threshold, a relay will open and stop a predetermined process line. This will reduce the KWH load to get the 15 minute average down below the fault threshold.

It is estimated that the manufacturer is saving about $70,000 per year. The project paid for itself in less then one year.

Indusoft integrates control between Genmark robot and Omron PLC controlled laser for wafer processing

Indusoft integrates Genmark Robot and Omron PLC

Indusoft was used to integrate a Genmark Robot with a Omron PLC controlled laser for wafer etching. The Genmark robot used a serial port for communication to the Indusoft PC HMI. The Omron PLC controlled laser used Ethernet for communication to the Indusoft PC HMI. VB Scripting was used in Indusoft to control sequencing between robot and laser. This is a temporarily set up and will be controlled with hardwire I/O point in the future.

Found loose wire from 2904 miles away.

This past week my customer was having issues with their spud winch #1 intermittently faulting out. We agreed to have conference call at 8am eastern time which was 5am California time. At this point, the drive was tripping out consistently which is what you want when troubleshooting. The large GE drive was indicating speed tracking error. This indicated a speed feedback problem. I had them try to run it while I monitored the drive speed feedback. There was no feedback at all even though the motor rotated several rotations before tripping out. I had my trusty electrician in New York measure the encoder supply voltage at the motor. He measured zero, not good. The encoder cable back to the drive is not a straight shot. The AC drive is actually shared between two motors, spud winch and an anchor winch motor. The feedback gets switched by a relay. I suspected the relay was bad, but it was okay. While on the phone talking to the electrician in New York I had him look for loose wires and he indeed found one. He tightened it up and the cranes spud winch was back in business.

Printing press unwinder going too fast!

Unwinder going too fast

Recently I had a customer who said the unwind section on their printing press was going too fast. In fact, they had no control at all. When the section was started, the motor would try to go full speed. The maintenance person told me he tried adjusting various settings on the drive with no effect. I went to the plant to see what was going on. The DC field on the motor was okay, it had field current. Then we discovered there was a DC tachometer on the motor used for speed feedback to the drive. It would make sense if the tachometer wasn't providing feedback, then the drive would try to go 100% on . I hooked up my voltmeter to the DC tachometer output and we turned the unwinder by hand, no voltage on my meter. We thought we might have a bad tachometer so we looked at the brushes on the tachometer and they looked fine. We then noticed we could turn the shaft of the tachometer independent of the motor. That's it, we had a loose tachometer coupling. We opened it up and found more than a loose coupling, we had a completely disintegrated coupling. See picture. To make sure the tachometer was good we turned the shaft by hand and measured the voltage output. We replaced the coupling and started the line up without issues.

HMI touchscreens get retrofitted on the “Left Coast Lifter” (LCL) floating crane.

The LCL is a behemoth floating crane that lifted huge pieces of bridge into place of the new eastern span Bay Bridge in San Francisco, CA. The LCL crane was designed by American Bridge and built in Shanghai, China by ZPMC in 2007. It floats on a huge barge and is pushed into place by tug boats. The floating crane can then manipulate itself to the exact position by using 8 anchor winches on the corners of the barge. Once in position, the four spuds (piles) are lowered into the bay mud to hold it in position. The LCL has a maximum lifting capacity of 1750 tons or 3.5 million pounds.

Epic Engineering, LLC of San Rafael, CA is the control systems integrator responsible for all the automation and controls aboard the floating crane. Epic has been servicing the LCL since 2008.

There are 18 AC variable speed drives/motors that move the boom, main hoist, anchor winches, and others.  A multitude of operating stations and sensors all feed back into the main computer (PLC) and logic determines allowed moves. Three 550KW diesel generators are onboard to supply the necessary power.

The HMI (human machine interface) displays the current status of all the motors, generators, and sensors. The HMI allows the operator to control which generators needs to be on depending on the required load. Any faults or alarms will be displayed and logged.

The originally supplied HMI’s (2) were two panel PC’s running Windows XP. The PC’s had standard hard drives and cooling fans. Over the years while operating on the salty bay air, the intake cooling fans started to rust and erode.  Also, the end of support for Windows XP spelled the demise for these panel PC’s.

Epic Engineering determined that a hardware and software upgrade was prudent. The old system was a master slave configuration. So if the master PC went down, so did the slave PC. The new configuration is two independent HMI’s. A fan-less panel PC running Windows 7 PRO and a 64GB solid state drive. These “no moving parts” PC’s will last much longer in the salty air. Of course when upgrading to Windows 7 the application software needs to be upgraded too. This gave us a chance to upgrade the firmware on all the GE PLC cards. The GE Machine Edition was upgraded from version 5.5 to 8.5 and Cimplicity 7.0 to 8.2. The new panel PC’s had dual network cards. One was used for the main PLC connection and the other was used to connect to 4G LTE modem that enabled us to VPN into the PC.

The HMI retrofit was completed and the customer now has an up to date and faster system that will last much longer. Plus, Epic now has the ability to monitor and troubleshoot the PLC system from offsite which can save the customer thousands of dollars in travel costs.

Joe Hiti – President – Epic Engineering, LLC

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