August 7, 2013
New MVS Survey
Oh behalf of HTStec, The LabSquad is pleased to inform you that their latest survey titled "LAB INSTRUMENT SUPPORT STRATEGIES TRENDS 2013" is now underway.
"Proper maintenance of laboratory instrumentation is an important consideration to ensure that lab assets remain available to researchers. Minimizing downtime makes the research process more efficient. A variety of support options are available from original equipment manufacturers (OEM), small third party independent service organizations (ISO), large multi-vendor service (MVS) providers and internal support staffs. Understanding the needs of lab users is essential for service providers to ensure customer success."
If you count on your lab instruments being in 'research ready; condition, please take a moment and fill out this most important survey. JUST CLICK HERE
July 22, 2013
Unlike a brushless DC motor which rotates continuously when a fixed DC voltage is applied to it, a step motor rotates in discrete step angles. Stepper Motors are manufactured with incremental steps per revolution of 12, 24, 72, 144, 180, and 200, resulting in stepping angles of 30, 15, 5, 2.5, 2, and 1.8 degrees per step. The stepper motor can be controlled with or without feedback.
Stepper motors work on the principle of electromagnetism. There is a soft iron or magnetic rotor shaft (rotor -= rotate...it spins) surrounded by the electromagnetic stators (stators = stationary...they're fixed locations). The rotor and stator have poles which may be teethed or not depending upon the type of stepper. When the stators are energized the rotor moves to align itself along with the stator (in case of a permanent magnet type stepper) or moves to have a minimum gap with the stator (in case of a variable reluctance stepper). This way the stators are energized in a sequence to rotate the stepper motor.
There are two basic types of steppers-- bipolar and unipolar.Unipolar
- A unipolar driver's output current direction cannot be changed.
- There are two sets of the coils for each phase in a motor.
- Only one set of the coils can be energized at a time.
- Each coil represents one phase.
- Driver's output current direction can be changed. 100% of the winding is utilized in the bipolar drive. That means the two sets of the coils in each phase can be connected either in series or in parallel to become one set of a coil
- Current direction changed from the driver creates another mechanical phase.
- The number of mechanical phases is always twice the number of electrical phases
- Bipolar drivers provide 40% more holding torque than unipolar drivers, but typically run at higher temperatures
For this last reason, proper heat dissipation is important with bipolar drivers. A bipolar stepper has 4 wires and Unipolar steppers have 5,6 or 8 wires. The rotor has a permanent magnet attached to it. The stator is made up of coils as shown in the image to the left. There are eight coils in this unipolar stepper motor. Every coil in the motor behaves as an electromagnet, when they are energized by electrical pulses. For this particular motor, the opposing coils are paired and each pair shares a common wire.You can see that there are five electrical conntections of the PCB (one common, and four to control each coil pairing).
Stepper motors tend to be less expensive than servo motors (more on servos in Part III), and they are easier to control due to the fact that their precise incremental movements do not require posistional feedback. Simply command this 'open loop' motor and the location is predictable. Now, if a pulley attached to motor shaft comes loose, or if a timing belt attached to the pulley were to lose a tooth due to wear, it is conceivable that the device being controlled could act in an unpredictable way (gets lost) and could fail (crash).
Stepper motor control circuits can be viewed with an oscilloscope.You would need to identify the driver chip or indexing controller being used and look at the pulse train (disconnect any pulleys first).with the motor attached. The motor itself can be tested with an ohmmeter. If you have a bipolar motor, place the ohmmeter between the positive and negative input terminals of each winding. The resistance of the two windings should be exactly the same. If not, the motor must be replaced. If you have a unipolar motor, place the ohmmeter between the positive terminal and the com terminal and then between the negative and com terminals. Do this for each winding. In each case, the resistance should be the same for all measurements; if not, the motor must be replaced.
July 15, 2013
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 rotor
- 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.
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
June 3, 2013
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.
May 14, 2013
“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 aremaking 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 providedfield 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. Thisis 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?
May 10, 2013
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 informationmissing. 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…
April 29, 2013
Not every instrument failure requires a call to the manufacturer (OEM) or an independent service organization (ISO). Some simple and common failures can be rectified by just about anyone with some common sense and common tools. Can’t help much with the common sense, but the tool part is a lot more straight forward.
***WARNING *** if you are not comfortable working with electricity please don’t mess around and call for help from you own facilities support folks or and ISO. If you kill yourself, don’t write me a nasty-gram from the afterlife.
The handheld DMM - Digital Multimeter (aka the voltmeter). The name voltmeter is used pretty loosely by a lot of tech’s and only describes one function of this device. Very capable DMM’s can be found at the local hardware store for under US$50. For a good tutorial click here.
Voltage - Most DMM’s can measure a wide range of AC or DC voltage. One of the most common problems when you fire up an instrument and get nothing is no AC power. Most US labs will operator on 110 or 200VAC. A zero volt reading means you probably have popped a circuit breaker. If the AC outlet you are plugged into had a ground fault button, try pressing the reset button and try again. If you get voltage at the outlet, but no action on the instrument, you may have blown a fuse. Not comfortable checking voltage? Try plugging the instrument into a known good working outlet instead. More knowledgeable techs can test DC voltages for printed circuit boards (PCB’s) inside the instrument. Most instrument power supplies will convert AC power into lower voltage DC power and distribute it throughout the instruments. Many PCB’s have incoming power marked at a connector coming from the main power supply.
Resistance - Resistance is a measure of a devices ability to restrict the flow of electrons in a circuit. If you crack open an instrument and see a charred component, it is likely a burned out resistor. If you can still see the value of that resistor (some have the value printed, others may use a series of colored bands), you can use the DMM to verify if it is blown (open circuit, infinite resistance). While you may be able to unsolder and replace this component, there is no guarantee that it will not blow again, as something else may have failed that caused too much current to flow thru it or too much voltage across it, causing it to cook. If you come across a cooked resistor (or any other component), better to have someone replace the entire module. Almost no FSE’s will spend time doing component level failure analysis as it is time consuming and ultimately more expensive.
Continuity – Some DMM’s allow you test for continuity (the closure of a circuit) that will result in a beeping signal. No beep, no continuity. A quick crossing of the probe leads will tell you what sound you are listening for. This is what you will use to check you fuses or diode. A diode allows current to flow in one direction only. Diodes can be checked by reversing the leads across the component. It should beep with the leads in one position, not beep in the other. Some instruments have a main fuse as part of the receptacle that the AC cord plugs into. MAKE SURE YOU UNPLUG THE INSTRUMENT BEFORE YOU DO THIS!!! You can pop this open and check if the fuse is good or not.
Current - Not really something I would advise a notice to attempt. While voltage is measured across a load, current is measured in series with a load. So, in order to check current, you need to break the circuit and use the DMM to measure current flowing through the meter as part of the circuit. Lots of potential to hurt yourself here…leave to a professional.
Temperature – One of the features of many digital mulitmeters versus their older analog counterparts is the inclusion of a thermometer probe. This can be very hand for diagnosing random failures that are related to run away heating problems - a common example might be an intermittent cooling fan failure. Try taking a cover off near the fan, tape the probe somwhere close and note the temperature during normal operation with fan running (and cover back on). Then open it up, and unplug the fan (replace the cover) and monitor the temperature increase. If you do this, be vigilant and don’t leave the instrument unattended. You are looking not only for a temperature spike but also abhorrent instrument behavior…so you want to be able to shut it down ASAP.
Okay, so there you have it. Some basic things you can do with a DMM. Just remember, when it comes to anything involving electricity, you should always consult with your facilities management. Never perform electrical testing alone and never in the presence of liquids (especially flammables). When in doubt…leave to someone in the know.
April 9, 2013
It’s been over 35 years since the movie Marathon Man came out and I still have a fear of dentists. That imagery has nothing whatsoever to do with the topic of this blog, but the title reference was too good to pass up…
Everybody who works in a research lab no doubt has had to go through a mandatory lab safety course or certification. Companies provide such training both to ensure the safety of their employees and processes as well as to avoid future litigation should an accident occur. What is not always as clear is how to ensure the safety of visitors, or in the case of instrument support, Beyond providing lab coats and safety goggles, there are a couple of basic precautions that can be taken to ensure the well being of visitors and support techs;
1) Contact Person – all visitors should have the phone and email info for an employee who has been through a company approved safety training program. Visitors should be required to seek out this person for any concerns they have prior to conducting their work, or in the event of an emergency. Also, make sure you have the techs emergency contact (work and personal) info in the event that person requires medical attention.
2) Disclosure – Make sure you inform the tech of any biological or chemical hazards regarding the instruments. Point out instrument decontamination certificates and give direction on how to dispose of wastes (chem wipes, q-tips, wear items, gloves, lab coats). Also let them know your protocols for dealing with reagent spills or exposure.
3) Evacuation Instructions – Let the tech know how to exit the building in the event of an emergency. In addition to typical lab accidents, in today’s world that could also include fire alarms, terrorist attacks, workplace violence). Point out any per-determined ‘rally point’ once out of the building. Also, let them know how to re-enter the building or sign out if they do not return so they can be accounted for.
4) Facilities Support – Never let a visiting tech hard wire equipment to your facilities electrical junction boxes. If such a need arises, have your own knowledgeable facility personnel on hand to disconnect power and supervise all work. Same goes for plumbing high pressure air lines or water lines.
5) Basic Safety Training – make sure the tech has received basic lab safety training from their employer. Ask in advance for them to bring a certificate of such training, specific to the visiting tech.
With a little bit of extra consideration, it is easy to ensure the safety of lab visitors. And, it your service tech looks even remotely like Sir Laurence Oliver in the photo above, don’t be surprised if he or she incessantly asks, “Is is safe yet?”
March 26, 2013
As many of you know, systems can be very expensive so end-users are making critical decisions on behalf of their employers, both on how well their money is being spent and what are reasonable expectations as to when the system will begin to show a return on that investment. There is always concern about that ramp up time and the problems you may encounter along the way, so the question of warranty becomes very important to the lab manager or principal user of the system.
Most system integrators go through a very similar process regardless of who the end user is. It generally all starts with a customer needs assessment, whereby a sales manager (usually accompanied by an Application Scientist) asks a number of questions prior to generating a system concept proposal. While it may seem tedious to the end-user, (I know what I want, why can’t these people just give me their quote?) this is a critical step in ensuring long term success. I have been involved in a number of situations where a customer had budgeted hundreds of thousands of dollars but could not provide a single manual method they wanted to automate. Not good.
Weeks (more like months) after the system is designed/proposed and agreed upon/purchased by the customer, a date is usually scheduled for a FAT (factory acceptance test) whereby the customer visits the integrator and goes through a “buy-off” checklist prior to shipment. This buy-off is best done with the actual customer methods (minus real chemistry) to ensure that the system performs as agreed upon prior to shipment. Remember, shipment means breaking down the system and packaging so that it can be “re-integrated” yet again upon arrival at the customer site whereupon it goes through the SAT (site acceptance test) which is basically the same buy-off as the SAT, albeit with actual chemistry. Once completed, you get a handshake (maybe a hug if it goes really well) and “TA-DA !”you own the system.
Most integrated systems come with a one year warranty. This can mean different things to different integrators but in my experience, entails parts and labor only (travel is not included). It also does not include operator induced failures like crashing a robot into an instrument. In general, most systems include a fair number of third party instruments that the integrator does not manufacture and they don’t make a lot of money providing them. These instruments come with their own warranties (usually 1 yr) and the integrator almost always passes these on to the end-user, acting as the first point of contact if a failure occurs. Since the instruments can often reside at the integration firm for several weeks prior to FAT, it is important for end-users to understand their warranty…’what is covered?’, for how long?’ and ‘when does the clock start ticking (upon shipment, acceptance)?’.
As mentioned in prior posts, an extended warranty for an integrated system can often cost 10-15% of the purchase price of the system. Some integrators offer an incentive (discount) if you purchase such an extension with they system, or prior to expiration of the standard one year warranty. Should you choose that option?
In short, the answer is no and I will tell you why. Let’s assume we are talking about a $350K ELISA system that includes a robot mover, bar code reader, liquid handler, plate washer, ambient storage hotels and plate reader. Those majorcomponents probably account for less than 50% of the price of that system. The remainder is comprised of things that don’t wear or break (system tables, enclosures, scheduling software, PC and …labor). That last one is a biggie. Integration is hard work and proper design, build, programming and testing prior to SAT can include hundreds of person-hours. That is commonly referred to as NRE or non-recurring engineering. A warranty for such a system could cost upwards of $50K, or more (not including travel) but you really should only care about the instruments…not the other stuff.
So, if you are faced with a decision regarding extending the warranty of your integratedsystem…push back. It’s pretty easy to determine the list price for each instrument in a system and request a contract that is based on just those costs. You could also go directly to each manufacturer and request contract pricing on their product only. If that is too time consuming or a management hassle you don’t need, you may want to reach out to one of the major MVS (multi-vendor services) providers (Thermo, PE, Johnson Controls, Agilent, GE) or smaller ISO (independent services organizations) like The LabSquad.
Don’t be nervous about system support…be informed.
February 13, 2013
With sincere apologies to The Bard, this is a quandry that is often faced by many lab managers when their facilities group or a vendor informs them that a preventive maintenance procedure is being scheduled.
How do you know when the time is right to actually do such work (spend money)? Just because the manufacturer recommends that a PM be done every 6 or 12 months, is that the right thing to do? What if the instrument rarely gets used?
All too often, lab managers or those whose budgets will be tapped for PM services are in the position of ‘erring on the side of caution’ or take a break/fix approach. Spending unnecessarily is obviously not desirable, however waiting till something breaks can cost dearly. There has to be a better way.
A number of common lab instruments have PC based controllers (liquid handlers, readers, integrated systems) and many of those instruments include ‘log files’, which are used by operators to troubleshoot assays or techs to repair instruments. Savvy lab managers and OEM’s can use these logs to track actual usage as opposed to just following suggested time intervals. It requires someone to actually look up the log files (if they exist) and be able to interpret the data but unfortunately there are not a lot of alternatives.
The LabSquad (caution: gratuitous self promotion ahead) is looking for off-the-shelf monitoring solutions that can be adapted to lab use. Other industries commonly use data logging equipment to monitor temperature or humidity but machine usage (especially outside of manufacturing environments) is relatively uncommon. Additional obstacles present themselves in that not all lab instruments use a PC controller and there are not a lot of inexpensive data loggers to choose from. Not to be deterred, we are also looking at custom developed solutions that could be added to any lab instrument which would monitor usage and be inexpensive (cost less than US$100). Just to make it interesting, we would like such devices to wirelessly communicate with a host PC or tablet such that someone could simply pass by a lab like the fellow who reads your home water meter does by driving by your house to assess the usage of key instruments.
While The LabSquad makes it’s living by performing PM’s and repairs, we do strongly believe that we can help labs better spend their support budgets by investing available support funding more wisely. Some instruments (the workhorses) might need more frequent attention, while lesser used devices might have their PM’s pushed out further.
As Paloneus says in Hamlet, Act 2 Scene 2; “Though this be madness, yet there is method in it.” Let us know what you think about PM scheduling and how your lab goes about keeping your instruments ‘research ready.’