Scilogex - 861431019999 SCI280-Pro Circular-top Digital Magnetic Hotplate Stirrer, 5.3" Diameter Ceramic Coated Steel Hot Plate, 280C Max, 200-1500RPM, 110V 60Hz, US plug

I bought the MS-H280 Pro hotplate and stirrer to provide a temperature stabilized liquid bath to characterize semiconductor parameter change with temperature. The features I needed were digital control of temperature, built-in stirrer and an external temperature sensing probe. The MS-H280 Pro met those requirements at a reasonable price and a suitable size.Scilogex has a promotion running for hotplates purchased during 2013 that provides a free platinum temperature sensor, a model PT1000 for the MS-H280. Adding the PT1000 sensor greatly increases the usefulness of the hotplate.As an aside for those not familiar with how temperature control works with the MS-H280 and other similar products, the user enters a set point temperature and the hotplate tries to maintain that temperature by comparing the set point with measured temperature. The default measurement sensor is built into the hotplate heating element but there's obviously the potential for a significant difference between the heating element temperature and, for example, the temperature of water in a flask being heated. The optional platinum temperature sensor plugs into the hotplate and can be immersed in the liquid being heated so that the commanded temperature is compared with the liquid temperature, offering the potential of precise temperature control of the target.To see how well the MS-H280 Pro controlled liquid temperature with the external probe, I heated 500 ml of distilled water in an Erlenmeyer flask with a stirring bar (200 RPM) and two temperature probes. One being the platinum control sensor and the second an Agilent E2308A thermistor connected to an Agilent 34410A digital multimeter, with logging every 10 seconds via an IEEE-488 bus to a laptop computer. I had previously verified the E2308A/32410A combination as within +/- 0.25 deg C at 0C and 100C.I manually incremented the MS-H280 set point in 10 deg C increments from 50C to 100C with approximately 60 minutes per set point and a final 60 deg C setpoint after the 100C run. The logged data was post processed and plotted.I found:1) the MS-H280 LED temperature display provides the sensor reading and over the 50-100C range where I compared the results it agreed with the Agilent sensor values within 1 deg C which is the MS-H280's resolution.2) Starting from room temperature and heating to the first setpoint of 50C, I observed about 1.5C overshoot, followed by a stable 49C plateau, with a small bit of ripple of about 0.5C peak to peak.3) I found no overshoot on any of the subsequent 10C increments; just the 0.5C ripple. The peak temperature seems to be the set point and when the set point is approached the control algorithm turns the heating element off. The liquid temperature coasts upward a fraction of a degree and then drops, at which point the heating element is enabled. There seems to be a bit of hysteresis (desirable for control loop stability) in the algorithm.4) I found no indication of undershoot in the 100C to 60C setpoint reduction.All in all, I'm very pleased with the MS-H280 and external platinum sensor.

First unit I received had defective temperature control and insufficient heat to boil water. Replacement unit took 10 days to arrive--very inconvenient. The second unit was in apparent "good" working order except that it is also useless (insufficient heat) for boiling water so I sent it back for refund.Update: They charged me $42 for restocking fee, even though their unit is defective! This company is not only falsely advertising the capability of the product, but they are also apparently comfortable stealing your money when you return their uselessly defective merchandise.I recommend DON"T WASTE YOUR MONEY--Buy elsewhere!So far I’ve had two of these things and both are useless for heating and boiling water. I measured 390 Watts using a calibrated (+/- 0.3%) digital power meter. These are NOT 500 Watts as it falsely says in their specifications. Subtracting some overhead for the power supply and controls the hot plate couldn't be more than about 350 watts.What's even worse is the thermo-conductive design is extremely inefficient; probably partially due to the ceramic coating on the burner surface and partially due to other factors. This thing takes about 40 minutes to bring 1 liter of water from ambient to 100 C, and then it never achieves a rolling boil -- only a few bubbles every few seconds. If you plan on using this for distillation or for making condensate, etc. - FORGET IT!I e-mailed the company telling them I suspected a defect and asked them how many watts the unit should draw - but they refused to answer my question, only telling me that I need to use a flat bottom flask. These guys obviously think like idiots because of course that's the first thing I did. I also made a special insulating ring out of silver-coated aluminum and fiberglass, which I placed around the hot plate and bottom of the flask. My setup had the maximum surface area in contact with the hot plate and an insulating "mantle", and still my liquid only absorbed 218 watts of heat energy (calculated, based on empirical measurements).I did every reasonable thing I could to get this thing to work and I tried two different units to make sure I didn’t have a defect; so it is my conclusion this thing is crap! And so are their customer support and their ethics for stealing my $42 restocking fee just to put the crap unit back in their inventory so they can sell it to the next sucker!

Would have given it a 5 star but it didn't include the PT1000 Sensor support rod & clamp for use with it. An extra 50 bucks which I think is a little steep. However the review I've see complain about not being able to boil water. I for one am not wanting it to boil water I have a tea pot on my stove for that. It works well holding temperature below 100c on water. I found that it can control the temperature of oils. It does over shoot the set point so adjusting the set point needs to be gradual. You have to be careful on adjusting the set point as it could jump a large amount or just go to lowest setting. I used regular cooking oil and some popcorn oil to test mine and it will take the temperature and hold very well. So It works well as and oil bath as long as you don't take the temperature high enough to burn the oil. Tested the popcorn oil up to 100c had no problem going up to 110c. Since the oil had butter added it actually kind of remove it as a buttery smell thru out the kitchen. So I know it works well with oil. So if you want to boil water it will not get to 100c at all. I could only get it up to 96c, but it will work with oil and hold it within -+1c. Since I'm not making rocket fuel I see no problem with the essential oil so far. 5star on that part so far.