July 15, 2013 by Kevin Keras

Motor Madness - Part I

If it moves...it probably has a motor.  There are a number of different types of motors within lab instruments and while repair or diagnosis of many of them are beyond the expertise even the most savvy field service technician, it is helpful to know a bit about them and what makes them tick (or spin).

The most common motors are simple AC or DC motors. As their names imply, each uses a different current scheme to achieve basic rotation but a simple brushed DC motor has five parts:

  • Armature or rotortl_files/labsquad/blog_images/Motor Madness/BrushedDCMotor2_opt.jpeg
  • Commutator
  • Brushes
  • Axle (shaft)
  • Field magnet

In many motors, the outer metal housing contains at least two field magnets (North and South).

The armature, also called the rotor as it rotates about the axel, is an electromagnet made by coiling thin wire around  two or more poles of a metal core.

The commutator is a pair of plates attached to the axle.  These plates provide the two connections for the coil of the electromagnet.

The commutator and the brushes enable for the "flipping" of the electric field" part of the motor.tl_files/labsquad/blog_images/Motor Madness/motor-labels.gif

Brushed DC Motors have two coils of wire around a rotor in the middle. Surrounding the coil are two magnets, both facing in the same direction. When the coils are facing the magnets, electricity flows into them. When electricity flows into a coil, it creates a magnetic field, and this magnetic field pushes the coils away from their magnets. As the rotor turns, the current shuts off. When the rotor has turned 180 degrees, each rotor faces the opposite magnet. The coils turn on again, this time with the electricity flowing in the opposite direction. This creates another pulse, pushing the rotor around again. The rotor has electric contacts on it, and there are small metal brushes that bump against the contacts. The brushes send in electricity, turning the motor on and off at the right times.

Operationally, all you need to do is apply the proper DC voltage at the nominally rated current and the motor will spin. For simple devices this can be done via an on/off switch.

A brushless DC motor has a permanent magnet on the inside of the rotor, such that its north and south poles are perpendicular to the axle. Coils surround the rotor.  These coils function similar to a brushed motor in that hey give out timed pulses to push the magnet, spinning the rotor. Because there are no brushes however, the motor cannot control itself. Instead, it is attached to a speed controller ciruit, which gives pulses of electricity at a certain speed to control the motor. The faster the coils pulse, the faster the motor will spin.  This is called Pulse Width Modulation or PWM (more on that in Part 3).

On a final note, other than brushes, there reall isn't much that can be easily fixed on a DC motor.  For older devices that are no longer supported, you can find rebuild services that can repair toasted armature (more common on larger motors).   The most tempting way to test a DC motor is of course to apply power...but please, if you do this make sure to disconnect the motor from any mechanical drive components (pulleys, bests, chains, linkages...etc) first.   As always, if you choose to ignore this advice, please do not send nasty emails, legal notices or graphic images of your physical injuries...

Next Up: Part 2 - Stepper Motors

 

(comments: 0) | Add a comment

June 28, 2013 by Kevin Keras

By The Book

Did you ever work with a field service engineer who was just plain awesome...someone who always went above and beyond to ensure your success?  If so, you have probably asked yourself ''what would I do without them? ' Sadly, that hypothetical question, all too often, becomes reality.

For any number of reasons (some good, some not so good) people are transient.  As the old saying goes, no one is truly irreplaceable, so the best protection vendors can provide for their customers is to ensure that more common procedures are documented. For example, irrespective of who is doing the work, a preventative maintenance procedure should always be the same. Each step, every tool, replacement part, lubrication or adjustment should be captured in a document that can be used to cross train FSE's so that your instruments always receive consistent maintenance.

Whether you are working with a new FSE to support a new install, or existing instrument don't hesitate to ask to see the procedure they will be following. Motl_files/labsquad/blog_images/By The Book/BookHead.jpgst vendors won't share all the details, but many will let you have a glance and most will provide checklist that highlights the work to be done.

If a vendor cannot produce documents for common procedures (like a PM). before they commence their work you should be concerned. I'm not saying that you are about to be mis-treated, however how can you be certain that the requisite work will be accomplished if there is no guideline? You wouldn't conduct an assay without a documented procedure and you shouldn't allow anyone to work on your instruments without one either.

If they can't show you 'the book', then throw the book at them!

(comments: 0) | Add a comment

June 21, 2013 by Kevin Keras

Multi Vendor Service Webinar

LabManager

LabManager Magazine annual webinar on multi-vendor services.[nbsp

Presenations from:

  • Agilent CrossLab
  • Thermo Fisher Unity Lab Services
  • Perkin Elmer OneSource


Click HERE to view. (takes a few seconds to load...be patient)

 

(comments: 0) | Add a comment

June 20, 2013 by Kevin Keras

Mike, Cancer & Chaos Theory

Big Mike

My friend and colleague Mike Williams was diagnosed with Neuroendocrine cancer. Also known as carcinoids, these slow growing tumors are often found in the digestive system (can also be found in the lungs and other organs) and are referred to as 'cancer-like'...but make so mistake, they are cancer by every definition of the word and those receiving a diagnosis similar to Mike's are often told to 'get their affairs in order...'

Unlike Russ, another friend of mine who lost his 2 year battle with a similar cancer last week, Mike was diagnosed over 6 years ago.   Mike has endured multiple surgeries and chemotherapy regimens as well as a long list of experimental drugs and drug cocktails.   Last month, he presented at the Midwest Lab Robot Interest Group meeting (LRIG) and spoke eloquently about the role automation and instrumentation has had on cancer patients from a first person perspective.   His talk can be viewed by clicking here.

In his closing comments, Mike points out that what many of us consider to be routine or mundane activities have real world implications for patients.  It's sort of like the butterfly effect... postpone an instrument service call or back order a critical component and you might delay an assay run that could yield novel data about a promising compound which could effect follow up studies, that then delays publication, resulting in missing a journal submission deadline that moves out the dissemination of clinically relevant info that might effect otherwise terminally ill patients...etc.

Mike is a shining example of perseverance, hope, faith and applied science.   I am so happy to see him presenting and grateful that he could take the time to share his journey with us.  I'll never look at a service request the same way again...  Godspeed Mike Williams.

(comments: 0) | Add a comment

June 6, 2013 by Kevin Keras

Power To The People!

tl_files/labsquad/blog_images/power-people/reddy-kilowatt.jpgOne of the most challenging problems faced by field service techs and engineers is intermittent failures that appear to have no discernible root cause.   Well…as least not an obvious one like a loose cable or belt.   More often than not, the most common cause of such failures is overlooked…electrical power.    Incoming AC (alternating current) power has been around so long that most of us take it for granted.  So long as the lights come on, we assume all is well.    That’s not always true.

In North America, most labs have either 110VAC  (actually somewhere between 105-125VAC) or 240VAC (for larger instruments like freezers or floor mount centrifuges). The AC power that feeds most lab instruments is converted into DC power via the instruments internal power supply which also steps it down to power integrated circuits, dc motors, relays, solenoids..etc (generally in the 5-24VDC range).    Power supplies are pretty robust devices that can provide constant, clean DC voltage, but like many things in life the quality of the output is a function of the quality of the input.  Garbage in = Garbage Out.

Unlike DC voltage which if looked at with an oscilloscope would show a flat line,  AC voltage is actually a sine wave and in most cases, the rated voltage of a circuit is represented by the avevoltagerage (RMS) of the voltages under the curve over time (usually 50 or 60 HZ or cycles per minute).   Now, garbage might be a harsh term but what we are really talking about are several common problems;

Voltage Spikes – Sometimes called a surge, a result of incoming voltage exceeding the rated voltage by 10% or more.   This typically happens when an inductive load (like a centrifuge) is turned off.   The centrifuge pulls a lot of current  and taking that load away (current) allows the voltage to quickly increase (ie, spike).   If an instrument has a well designed regulated power supply then no problem, but transient spikes (think lightening) have been known to take out the best designed power supplies.

Voltage Dips – a temporary drop of  more than 10%  (ex: 120V * .9 = 108V).  Probably not a killer, but what if your device is spec’d at 120V and the input line power is only 110VAC?  Now with a voltage dip you are talking 99VAC …  Some instrument power supplies have the ability to detect under voltages and report errors, many do not.   And…guess what usually happens after a dip?   You guessed it, a spike!

Noise – AC-powered devices can create a characteristic hum at  multiples of the frequencies of the AC power that they use.  Hums are commonly produced by spinning motor and transformer core laminations vibrating in time with the magnetic field.   The noises can wreak havoc on under-voltage situations as they can temporarily cause an instrument on the hairy edge to work temporarily.  Shut the noisy device off and the line dips down again causing the instrument to fail (or act really weird).

What to do if you suspect power issues?  Well for starters, whenever an instrument starts to show ‘random’ failures;

  • Have facilities verify incoming power.  A digital voltmeter can be used for this, but make sure they are using the RMS (root, mean, square) setting to capture the average voltage.   When in doubt, put a scope on it.  Scopes can also show noise as well as nominal voltages.
  • Isolate the instrument in question.  Make sure there are no other devices on the same circuit.
  • Put a digital or analog chart recorder on the circuit and monitor the line over chart recorderseveral days. Sometimes called a strip recorder, the analog version looks like the lie detectors you see in crime shows.  A needle draws on the paper producing peaks whenever it sees a spike or dip.  Newer digital units do the same thing but are much less intimidating to  less truthful members of society…
  • Note the time that failures occur.   Not surprisingly, spikes and dips tend to occur in larger facilities when people arrive at work, go to lunch, take breaks or go home around the same times.   PC’s , HVAC,  lights are turned on/ off – all in the name of conservation…the laws on unintended consequences.
  • Plug the instrument into  a line conditioner, then plug the conditioner into the circuit.  Power conditioner are good for removing noise and higher-end models (don’t go to Home Depot for this…) offer some protection for spikes and under-voltages.   Not to be confused with Un-interruptable Power Supplies (UPS) which offer a measure of time insurance in the event of a total power loss.   Even basic UPS’ are available with spike and dip protection but even without they are still not a bad investment if you have dirty or unreliable incoming power and no easy way to fix it…

Net/net – don’t be so quick to blame an instrument for abhorrent behavior.   Sometimes it is best to recall a bit of Shakespeare…”the fault dear Brutus lies not in our stars, but im ourselves (or our facilities).”

(comments: 0) | Add a comment

June 3, 2013 by Kevin Keras

Good Reads about Multi-Vendor Support

Thought I would share a few articles and interviews that talk about Asset Management and Multi-Vendor Service support.

Next Generation Pharmaceutical-Outsourcing Asset Management,  Bob Moore – GE Healthcare, interview

Lab Manager Magazine – The Evolving Service Model   ; Good overview of service offerings from GE, Agilent, PE and Thermo Fisher.

BioScience Technology.com – Managing More Lab Assets

GEN – Lab-Asset Management Gets Smarter; older article (circa 2008) but shows that Asset Mgt within life sciences has been around for awhile.

(comments: 0) | Add a comment

May 21, 2013 by Kevin Keras

Separation Anxiety?

Most labs have used floor mount or bench top centrifuges for separation based assays for decades.  Whether spinning samples to remove air bubbles, spinning down cellular debris or isolating supernatent, there are numerous manual access centrifuges on the market, but when it comes to automation, the choices are limited.

For a number of years, Agilent (formerly Velocity11) has offered the compact VSpin.  VSpin has a two position rotor with buckets for std microplates.   It can spiV11_prod_big_vspinn up to 300o rpm/ 1000g and has an automated door that allows direct access to plates using an offset robot gripper.   Units can be stacked on top of each other for increased  use of vertical workspace.  The Optional Access2 loader can also grab the plate and present it externally to a liquid handler gripper or top loading plate mover like Twister2 or KiNEDx.

Hettich also provides a larger unit called the Rotanta 460 which can accommodate 4 plates at speeds up to Hettich_Rotanta_46_RSC_Front_Hatch6200prm,  but is a bit more of a challenge to integrate as the robot gripper fingers need to reach into the unit from the top.  I have seen this done with Mitsubishi and Staubli robots and Tecan actually integrates this unit under an EVO liquid handler accessible via an open locator in the deck.Ixion3

Sias’s Ixion is a compact unit, similar in size to the VSpin, however plate access (total of two) is through the top just like the Rotanta and can spin up to 2000rpm.   This unit integrates nicely with Sias’ Xantus liquid handlers.

Finally, BioNex offers the HiG centrifuge which can also spin two plates.  The bright orange color makes this unit hard to ignore…and a closer look shows that this unit may be BioNex HiGthe best of the bunch.   With an automated lid that retracts from the top, the HiG does not need a plate loader like the VSpin as plates can be accessed by just about any robot gripper.   At 5000g, BioNex claims this unit to be the fastest robot accessible centrifuge available.

Maintenance requirements for each of these devices is similar.   All include high-speed motors so proper ventilation is a must.   Bearings must be greased, sensors cleaned and pneumatics (door opening, plate loaders) checked for leaks.   Additionally, rotors and buckets should be checked for cracks or other signs of wear.   As noted in previous blogs, rotational speeds can be verified using a digital tachometer but you may need to remove covers to gain access to the rotor (kids, don’t try this at home…call a professional).   As always, if you ignore that last piece of advice, don’t come crying to me when your friends make fun of you because you have a mircrotitre plate permanently embedded in your cheek…

(comments: 0) | Add a comment

May 14, 2013 by Kevin Keras

Every Picture Tells A Story, Don’t It?

A picture is worth a thousand words…so even at a reduced frame rate of 15FPS, one minute of video has to be worth 900,00 words.” – Me

For better or worse, advances in cellular communications arecameraphonemaking the once seemly impossible, trivial.  Specifically, I am referring to video communication.   Just about everyone has a ‘smartphone’ these days and it is hard to find a new phone that does not include a camera.   The resolution of these cameras is incredible (the Apple iPhone 5 = 8 MegaPixels) and product stunningly clear videos and images.

Video applications such as Apple’s FaceTime and Skype make face to face remote communications simple, fast and cheap.   For service organizations, this has providedthermal imagingfield based techs with an incredible tool for diagnosing instrument failures.    There are even iPhone apps that now allow users to perform thermal imaging (how cool is that…no pun intended)!  Let’s face it, the pressure these on-site techs feel when faced with a failed instrument can be enormous.  End user anxiety and a ticking clock only add to the stress.   The ability to ‘phone a friend’, point the phone at the instrument and have a real-time conversation about such failures brings an added dimension to peer review.

On the wired side, I have visited many research labs that have added low-cost USB or Ethernet cameras to their automation systems that allow them to monitor status remotely (many times from home, over a weekend or at night).   When combined with remote network access tools like PC Anywhere or LogMeIn, it is possible to deal with simple application errors and continue assays or applications that would otherwise had to wait for human to come into the lab and simple press a key.   Remote observation in this fashion requires network access and must always include IT departments to prevent unauthorized access.

Still, many labs will not allow non-employee cameras or video use within their labs.  Thisskype5is short-sighted (IMO), and unfortunate.   I understand the competitive nature of pharmaceutical or biotech research and the commercial implications of potentially providing competitors with a glimpse of a labs inner workings, but let’s face it…it would take a pretty savvy bunch of people to gleam something worthwhile from a phone camera.  Instrument failures that render an instrument ‘down’ are generally easier to diagnose and repair, however it the aberrant or irregular failures that could benefit immensely from remote observation.   Unless an instrument or system is under a service contract it can be very expensive to pay for a service tech to sit and watch for a reported failure (they always happen when the tech leaves, right?).

Most labs require non-disclosure agreements or safety training prior to granting non-employees access their labs and the time is well past to include the use of remote diagnostic tools, particularly cellular video in such protocols.   Perhaps seeing is believing?

(comments: 0) | Add a comment

May 10, 2013 by Kevin Keras

What is the opposite of TMI?

I am a big fan of Lab Manager Magazine.   I am an on-line and print subscriber anlab managerd find it to be a great source of information regarding lab trends and support.

Having said that…I was a bit disappointed by a recent “Ask The Expert” interview by Tanuja Koppal, PhD.  It was called “Optimizing Lab Services: Evaluating the Single-Vendor Option.”   You can read the full article by clicking here.

Although there are some good insights there were some major pieces of informationthe-godfather-brando-150x150missing.  For starters, it does not mention who the subject of the interview is.  I will give Dr. Koppal the benefit of the doubt and assume the interviewee is not fictitious, but I have a hard time understanding why he/she would need to anonymized.   Is there an MVS Mafia out there that requires a witness protection program?   Secondly, all the MVS providers whom the user evaluated are also anonymized.   I guess I could understand that given that many of these larger providers may have legal teams that would give any crime syndicate a scare.

In the spirit of peer review, I think it would be extremely helpful to both MVS providers and potential customers to know who this customer is and how they made the selection they did.

Who knows, using this feedback, maybe next time they need a contract, someone would be able to make them an offer they couldn’t refuse…

(comments: 0) | Add a comment

April 29, 2013 by Kevin Keras

Well Equipped…Part II

WD40 Duct Tape Flow Chart“One only needs two tools in life WD-40 to make things go, and duct tape to make them stop.” –  G. Weilacher

While true in many facets of instrument support, there is one other tool which lab support techs will find invaluable – the digital tachometer.    A more precise name would be a strobe tachometer, which neatly describes the basic theory of operation…a strobe light which is used to monitor the rotational speed of the rotor.

The LW Scientific Hand-Held tachometer can be found at a variety of web stores for under $200.   

tach

This device is easy to use and comes with reflective tape targets that you can place on the rotor arm.  Simply point the tach at the rotor in the general area of the target and hold it steady…after a few seconds you will see a reading that while changing, stays within the commanded speed.   This device can monitor speeds from 20-50,000 RPM which makes it ideal for most lab centrifuges and has a range of 50-400mm.  It’s accurate to +/- 20 RPM, so obviously you would want to be a bit skeptical at the low end range…

Interestingly, most separation assays call for acceleration of the sample not the rotational speed.  From a repair or assay integrity perspective, checking RPM’s will suffice as a general method to determine that the instrument is performing as specified by the manufacturer.    For those who are more curious, there is a great Wiki with more info.

Some centrifuge brands have sight glass windows that allow the digital tach to observe rotor speed while the unit is running…others do not.  Now comes the inevitable caution…caution! (notice I even used an exclamation point).    Seriously, most centrifuges Beck_L8are capable of causing great physical harm due to their extremely high speeds.   Safety interlocks that prevent internal access while spinning are there for a reason.   While a trained tech can defeat such locks, it is not advisable for a novice.   If you any doubts click this image to learn how dangerous high-speed centrifuges can be…

Manufacturer or third-party FSE’s re-calibrate the speed of a centrifuge by adjusting one or more potentiometers on the control board.  Initial speed setting is typically done without a rotor in the unit.

One last caution kids…speed kills.   Let’s be careful out there.

(comments: 0) | Add a comment