WeatherStation User's Manual
Contents
1. PrecisionControl We Control Your Environment WeatherStation User s Manual All right reserved Page 1 of 15 Precision Control LLC March 2006 ENVIROMENTAL CHAMBER INSTALLATION INSTRUCTION Unpack system Remove system from the box and remove eight thumbscrews Note don not remove thumbscrews covered with red tape Remove Do not remove cm Using 3mm wrench remove microscope nosepiece as shown on picture bellow A Remove camera cover All right reserved Page 2 of 15 Precision Control LLC March 2006 om Remove two plugs from microscope stand ref picture bellow Da Remove back panels from chamber and install them on the microscope base All right reserved Page 3 of 15 Precision Control LLC March 2006 Ta Remove Temperature controller from the chamber install it next to the microscope base Remove temperature control sensor from plastic bag secured on the top of temperature controller and install it on the Microscope pillar or Route X amp Z motor cables as well as temperature control sensor cable underneath Y motor Install and secure Y motor cover Saal with two M3x10 SCs oe Lower all the way down DIC support unit Secure microscope tower All right reserved Page 4 of 15 Precision Control LLC March 2006 10 Carefully install main component Note Enclosure should be slightly tilted when installed 11 Using eight M6x20 thumbscrews secure bac2. airflow setting for a quieter operation The higher airflow also improves the uniformity of the temperature in the chamber and capability of controlling larger cambers A BNC connector provides an analog temperature measurement output for a chart recorder RS232 communication provides software driven full control of WS Operation The POWER switch controls the main power for fan heater and microprocessor controller The HEATER switch controls only the heater when this switch is off and POWER is on the controller and fan will still be powered WeatherStationBT may then be used as precision digital thermometer with better than 0 2 C accuracy and 0 1 C resolution Fan Speed Control The fan speed control nub on the front panel will control the airflow rate from 20 to 50 cubic feet per minute CFM Lower flow rate will offer a quite operation and is suitable for most of application However the higher flow rate can generate more turbulence so that the temperature in the chamber will be more uniform It will speed up the heating and allowing controlling larger size chamber For safety reason the fan can t be turned off unless the instrument is off Caution void blocking the airflow Although a built in thermal cutoff switch is designed to reduce the hazard fan failure or obstruction in the airflow has the potential for overheating the system and damaging the instrument or even causing a fire All right reserved Pa
3. units used by the WeatherStation When this is changed all temperature settings are automatically converted S dEC Set Decimal Places Decimal places of precision to display temperature can be measured up to 1 degree resolution Ftr E Input Filter OFF no filtering diSP filter only the display value Cont filter the control input values both display and input values are filtered If a system has a lot of random temperature fluxuations Ex sensor is in a box with turbulent air flow the derivative term in PID control will not give appropriate feedback unless the input is filtered FLtr Filter Value O to 60 seconds Power Output Options PL 1 Power Limit maximum heat 0 to 100 if set to 80 a PID calculated output of 80 or 100 will both give 80 Value of 50 will also give 50 PSL 1 Output Power Scale Low actual power output when the controller is set to 0 PSH 1 Output Power Scale High actual power output when the controller is set to 100 If the low scale is set to 20 and high is 40 then a PID calculated output of 50 will give an actual output of 30 If the power output that is required to maintain the temperature set point is not between 25 and 75 either adjust the scale parameters or change the fan speed appropriately Unit Units of Measurement Determines PID units US or SI Ramping Control RP Ramping mode OFF no ramping Str ramp at startup On ramp at startup and All right reserved Page 14 of
4. 15 Precision Control LLC March 2006 when the set point changes RP Sc Ramp Scale hours or minutes RpP rt Ramp Rate degrees per unit hour or minute as chosen in RP Sc Temperature Re Transmit A01 U Analog Output Units volts or milli amps voLt or MA 03 Lo Analog Output Scale Low 03 hi Analog Output Scale High rl So Retransmit Source current temperature or temperature set point Proc or SP r3 Lo Retransmit Scale Low r3 Hi Retransmit Scale High r3 CO Retransmit Offset Example Set rl So Proc and AQ1 U volt to make it retransmit the measured temperature in volts Set 03 Lo 0 03 hi 10 r3 Lo 0 and r3 Hi 100 to make 0 to 100 degrees translate to O to 10 volts Changing the temperature sensor The controller starts out on the Home page WS temperature sensor a Pt 100 DIN RTD has been matched with the controller If the sensor must be replaced the system should be recalibrated To recalibrate fill a beaker with distilled water and ice made of distilled water There should be more ice than the water in the beaker Put in a magnetic stirrer bar and stir the ice water beaker on a magnetic stirrer Connect the sensor to the instrument place the sensor in the beaker of water and wait for 15 minutes or until the temperature reading on the instrument stabilizes The reading should be zero If it is not zero get into the Programming page by holding down then pressing and holding both for about 6 seconds Press
5. ations menu press The Total heat power is the sum of the three PID terms Power Heat Po ht 100 ProP it dE The proportional and derivative terms range from 1 to 1 and the integral term goes from 0 to 1 The PID controller determines the magnitude of each term from temperature measurements and the values of three PID parameters ProP it and dE In All right reserved Page 9 of 15 Precision Control LLC March 2006 the following table AT T SV where T is the current temperature and SV is the temperature set value Term Parameter Paremeter Units Equation Proportional ProP Proportional Band Heat Pb ht DegreesC ProP 1 Pb ht AT Integral it Integral Heat It ht Minutes it 1 It ht 1 Pb ht AT dt Derivative dE Derivative Heat dE ht 1 Minutes dE dE ht 1 Pb ht d AT dt The proportional term looks at the current value of AT the integral term evaluates how long it has been there and the derivative term depends on how fast it is changing The heat power is always 100 if AT lt 2 Pb ht and 0 if AT gt 2 Pb ht When IAT is less than twice the proportional band the derivative term slows down the approach rate to help keep the temperature from overshooting the set point When ATI lt Pb ht the other two terms are activated The proportional term can bring the temperature within a few degrees of the set point by itself but not all the way since dE 0 when AT 0 The integral term adds the
6. dE ht 0 06 These parameters are determined by the auto tune process for a typical condition If the stability is poor the user can use the auto tune to adapt to the special condition Put the temperature sensor very close to the subject and let the outlet hose blow the air directly onto the subject Note that the heat output scale can be controlled with this system by simply adjusting the fan speed Analog temperature read out The BNC connector on the rear of the WeatherStationBT case is for temperature read out It is set at slope 50 mV C and a range from 0 C 0 V to 200 C 10 V For example at 50 C the read out should be 2 5 V Slope and range can be changed in the secondary menu Accuracy will be 1 of range If greater accuracy is desired adjust sensitivity and offset of recording device to match the reading on the WeatherStationBT panel Please note that the input of the recording device should be off ground The outside of the BNC connector therefore should not be grounded Grounding the outer shell of the BNC may seriously interfere with proper recording Watlow Controller Functions Front Panel WATLOW 1 2036 All right reserved Page 12 of 15 Precision Control LLC March 2006 Up Key Increments a value or changes a menu item Down Key Decrements a value or changes a menu item Advance Key Moves to next menu item Qo O Infinity Key Returns to Home page The controller starts out on the H
7. e sheet at the front of the air entrance Varying the distance between the port and the plate to make the temperature more uniform Connect the temperature sensor to the WeatherStation Feed the temperature sensor into the chamber and place it at the desired position Most common position is at the back stage of the microscope Turn on WS POWER switch Use O and v to adjust the temperature set point on the lower display to the desired value The upper display shows the temperature reading from the sensor Turn on WS HEATER switch and the system will start to work It might take 30 40 minutes for the air inside a chamber to stabilize from room temperature to 37 C Automatic control This uses PID Proportional Integral and Derivative control to automatically find the heater power output necessary to reach and maintain the temperature set point Three parameters can be adjusted to optimize it for different systems These can be entered manually or determined automatically by the controller Auto tune The controller will evaluate the process and select the PID values to maintain good control Once the user starts a learning process the controller lets the temperature go up and down three to four times until good PID parameters are established After auto tuning it immediately begins regulating the temperature using these values Manually setting PID values In this mode user can manually adjust the PID parameters which appear in the Oper
8. eater The smart controller responds quickly and precisely to thermal changes while maintaining temperature control WS can be adapted quickly to different environments by selecting one of three operating modes Auto tuning manual tuning or standard Proportional Integral Derivative PID tuning One of the main applications of the WS is for controlling the temperature of a chamber not included that covers live cell imaging systems in which a stable and uniform temperature of the sample and optics is essential With WS the temperature of the sample and optics can be controlled within 0 2 C During the operation the air is drawn out of the chamber through the flexible hose heated at WS heater and then re circulated back to chamber by the return hose The temperature sensor can be placed at the air outlet of the hose or near the sample where the temperature control is most critical This configuration allows the entire optics of the imaging system to stay at a uniform and stable temperature without any drift No vibration noise is introduced because the WS can be placed away from the optical isolation table The sensor is also electrically quiet The temperature sensor is shielded for very high impedance recording The newly improved WS provides more than three times more airflow than the original model The airflow rate is also adjustable It allows the user to use the high speed flow to speed up the initial heating up and then use the lower
9. ed by derivative action If reducing dE ht does not make the system more stable try increase the input filter value make sure Ftr E is set to Cont and adjust FL tr to desired number of seconds See the Temperature Input Options section of the Setup page in the appendix If it is particularly difficult to stabilize your system try decreasing the heat output range The heat output range should be adjusted so that it takes about 25 to 75 of the heater power as shown by the Po ht parameter to maintain the temperature set point The heat output range can be adjusted with parameters in the Power Output options section of the Setup page in the appendix Here are some examples of PID parameters for systems with varying response times Slow response process Pb ht 7 It ht 20 0 dE ht 1 67 All right reserved Page 11 of 15 Precision Control LLC March 2006 Normal response process Pb ht 4 It ht 7 0 dE ht 0 58 Fast response process Pb ht 3 It ht 3 0 dE ht 0 25 Manual control The operator manually controls the percentage of the total power of heater that is used Go into this mode by setting Pb ht to MAn The lower display in the HOME position shows the output in percent Using WS as a constant temperature blower This is an easy method to provide a constant temperature for a small subject To do this leave both the air inlet and outlet hoses on the instrument Set the controller parameters to Pb ht 3 It ht 4 2
10. ge 8 of 15 Precision Control LLC March 2006 Temperature Sensor The sensor is shielded and grounded with a stainless steel sleeve The sensor can be directly inserted near sites that involve electric recording without introducing any interference from the heating unit It can be safely placed in water but it will ground the system unless a moisture resistant coating 1s applied We recommend using silicone or epoxy to coat the stainless steel portion of the sensor The coating should not be applied unless it is absolutely necessary since it will slow the response time Applications Using WS with chambers that covers the live cell imaging microscope System The circulation of the heated air will make the temperature easier to control keeping the humidity and preventing potentially dangerous sample from pollute the laboratory environment In order to achieve temperature uniformity we recommend the heated air to be introduced to the top of the chamber and cold air to be sucked out from the lower part of the chamber Because the hotter air is lighter and tends to stay on the top this arrangement will cause more turbulence and make the temperature more uniform Ifa uniform temperature for a large area is needed both in flow and out flow air should be baffled A simple baffle can be made by drill some 10 mm holes evenly distributed on a piece of acrylic sheet The number of holes and size of the plate will depend on the size of the chamber Place th
11. integral term is zero since it resets every time the temperature passes outside the proportional band Therefore the total heat output is 1 0 0 0 0 1 90 After one minute the proportional term has changed to 1 5 34 37 0 6 and the integral term has increased to 1 It ht 1 Pb ht AT dt 1 4 1 5 4 0 2 The new heat output is 0 6 0 2 0 1 70 All right reserved Page 10 of 15 Precision Control LLC March 2006 Of course this is assuming a constant d AT dt A real system is more complicated since the decrease in heat output as the set point is approached will slow down the increase in temperature The diagrams below show the temperature and PID parameters as the set point is approached in a well tuned system The temperature is in degrees Celsius and time is in seconds 600 seconds 10 minutes 100 200 300 400 500 600 Proportional nt edral Derivative 1 2 1 0 8 0 6 0 4 0 2 0 0 2 0 4 0 6 0 8 1 2 I An easy way to use this mode 1s to use the Auto tune first to get a preliminary value then to manually fine tune the system If the integral action is too small large It ht or the proportional band Pb ht is too big the temperature will take a long time to reach the set point However making the values of It ht or Pb ht too small will make the system unstable causing oscillations about the set point Oscillations about other points besides the set point are usually caus
12. k panels Note Tighten thumbscrews only after all of them have been Installed Ae BBS iis T Se FEN Hisa 12 Connect and secure two hoses to the hose connectors on the chamber Note reference diagram below for proper orientation E All right reserved Page 5 of 15 Precision Control LLC March 2006 Hose Connection Diagram Chamber AIR IN AIR OUT Temperature Controller AIR OUT 13 Connect temperature control sensor and power cable to temperature controller 14 If applicable connect CO2 tube to push to release connector marked CO2 Port 1 on the back of the chamber All right reserved Page 6 of 15 Precision Control LLC March 2006 15 Replace and secure microscope nosepiece place CO2 humidifier bottle and CO2 and connect CO2 tubing 16 If applicable chamber inside main enclosure according to the labeling x i al d 4 ida hS i 4 E E Fr F _ _ ai ai ai i _ _ a ii a 17 Follow the User s Manual instructions to set desire temperature settings All right reserved Page 7 of 15 Precision Control LLC March 2006 For WeatherStation Temperature Controller is a precise temperature controlled air heater for bioscience laboratories Sending temperature controlled air directly to the site provides an attractive alternative to a heated water bath or electric h
13. mperature controller from the SI to the US system rE ht Reset Heat repeats per minute Used in US system It is equal to 1 It ht dE ht Derivative Heat derivative time in minutes Used in SI system rA ht Rate Heat rate time in minutes Used in US system It is exactly the same as dE ht All right reserved Page 13 of 15 Precision Control LLC March 2006 h hyS Heat Hysteresis How far the temperature goes below the set point before the heat turns on Used only when heat control method is set to on off ProP Proportional Term View the active proportional term for PID diagnostics it Integral Term View the active integral term for PID diagnostics dE Derivative Term View the active derivative term for PID diagnostics Notes The PID parameters are only visible if the heat control method ht M is set to Pid Others are only used when the controller is in US or SI mode see the Unit parameter in the Setup page Setup Page Hold down O and v for 3 seconds to get to setup menu moves from one parameter to the next The setup page contains settings that are not needed as often as those in the Operation page This section of the manual will list the parameters that are relevant to the operation of the WeatherStation Any which do not appear in the list should not be changed Parameters are grouped into categories in this list in order to make them easier to find Temperature Input Options C F Celsius Fahrenheit Sets the temperature
14. necessary offset by continuously increasing at a rate proportional to AT If the system starts losing heat ex someone opens the chamber door the derivative term will detect the rapid drop in temperature and increase the power output accordingly The heat output is usually zero above the set point since the proportional term is negative in this region and the integral term is usually zero However the integral term will still be positive if the temperature has just passed the set point and the derivative term will be positive if the temperature is approaching the set point from above In some cases the sum of these other terms will be greater than the proportional term so the WeatherStationBT will still be heating the chamber even though it is already hotter than the set point This situation makes more sense if we remember that heat has to be constantly added in order to cancel out the heat lost to the air surrounding the chamber If 40 heat is required to maintain the temperature at the set point then 39 will cool it down Here is an example of a possible PID setting Temperature Set Point SP 37 C Proportional Band Pb ht 5 C Integral Heat Time It ht 4 minutes Derivative Time dE ht 0 5 minutes Suppose that the current temperature is 32 C and is rising at 2 C minute At this point the proportional term is 1 Pb ht AT 1 5 32 37 1 0 and the derivative term is dE ht 1 Pb ht d AT dt 5 1 10 2 0 1 The
15. ome page Press to scroll through the Operations page Hold down O and v for 3 seconds to go into the Setup page Press at any time to return to the Home page Home Page Temperature Current temperature of probe Always present on the upper display Set Value Temperature set point Appears on the lower display when in Automatic mode Percent Heat Output Appears on the lower display when in Manual mode Can be set anywhere from 0 to 100 If A M is set to Auto Po ht can t be manually changed but it will still appear in the Operations page for diagnostic purposes Operations Page Po ht Power Heat When A M set to auto shows instantaneous percent heat output A M Auto Manual Mode Set to Auto or MAn In Auto mode heat is controlled according to the ht M setting In manual mode the user inputs the percent heat output Aut Autotune On Off appears if A M set to Automatic When turned on the upper display on the Home page flashes tune until the unit is done auto tuning ht M Heat Control Method OFF Pid or on of Pb ht Proportional Band Heat determines temperature band in which PID control is used Proportional and integral controls are active within Pb ht of the set point and derivative control is active within 2 Pb ht All PID parameters including Pb ht only appear when ht M set to PId control It ht Integral Heat minutes per repeat Used in SI system The Unit parameter in the setup page changes the te
16. to scroll to P4 and change it from none to Cal Press to return to the Home page and scroll through the Operations page till you get to the newly inserted calibration offset parameter Adjust the calibration offset until the temperature reads zero Afterwards it is a good idea to go back into the Programming page and remove CAL from the Operations page so that it is not accidentally changed For more information visit www watlow com Contact Information Email hotline precitioncontrol net Website www precisioncontrol net Phone 253 203 6264 Fax 253 203 6265 All right reserved Page 15 of 15 Precision Control LLC March 2006
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