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J-KEM Scientific Gemini, User Manual

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J-KEM Scientific Gemini User Manual Download Page 11

 

11

 

3.2 Heater 

Restrictions.

     Each channel of the controller can individually deliver up to 10 amps of current at 

120 VAC, but the combined total current from Channels 1 & 2 can not exceed 15 amps.   These current 
ratings are limited to resistive loads (heating mantles, hot plates, ovens, etc.).   

Use only resistive loads 

that are safely operated at 120 VAC and require less than 10 amps

 

or damage to the controller and a 

safety hazard may result.

 

 
• 

Do not plug oil baths into your controller.   Oil baths are not 120 VAC devices and become a fire 
hazard unless properly connected to the controller.

   (See Appendix for an application note 

describing the use of oil baths with this controller).  Ask about J-KEM’s new 400 series controllers for 

use with oil baths. 

 

 
 
3.3 

Ramp-to-Setpoint & Soak Feature.        

A new feature of J-KEM’s controllers called ‘Ramp-To-Setpoint’ 

allows you to enter a specific heating rate (e.g., heat to 120

o

 C at a rate of 5

o

 C/Hour), a second feature 

called ‘Soak’ then lets you specify how long to stay at that temperature before turning off.    Single and 

multi-step ramps can be run using KEM-Net software. 

 

Examples of Program Ramps 

 

Setpoint

Temperature

Time

Ramp

Soak

Power Off

Setpoint

Temperature

Time

Ramp

Soak

Power Off

 

 

 

The controller is shipped with the Ramp-to-Setpoint feature OFF, the user must specifically turn Ramp-to-

Setpoint ON.   When Ramp-to-Setpoint is OFF, the controller  heats to the entered setpoint at the fastest 

rate possible.   When Ramp-to-Setpoint is ON, the controller heats at the user entered ramp rate. 

 

The Ramp-to-Setpoint feature and its associated parameters are turned on and set in the controller’s 

programming mode.   The parameters of importance are: 

 

SPrr

   

SetPoint Ramp Rate.   Allowable Values:  0 to 9990 deg/Hr.

 

This specifies the rate of heating (cooling).   Note, this parameter specifies the 

desired

 rate of heating 

(cooling), the actual rate of heating is dependent on heater power.

 

 

SPrn

 

  

SetPoint Ramp Run.   Allowable Values:  ON, OFF, Hold

 

This parameter turns the Ramp-to-Setpoint feature ON or OFF.   During an active run, if this parameter is 

set to ‘Hold’, the setpoint ramp stops and 

holds

 at its’ current value.   This continues until the parameter is 

set to ON or OFF.    When set to OFF, the values in SetPoint Ramp Rate and Soak Time are ignored. 

 

SoAK

 

  

Soak Time.    Allowable Values:  “- -”, 0 to 1440 min.

 

This specifies the amount of time to 

soak

 at the setpoint after the temperature ramp is complete.   A setting 

of 

“- -”

 causes the controller to remain at the final setpoint indefinitely.   A numeric value causes the 

controller to stay at the setpoint for the entered time and then turn power off after the time expires. 

 

Summary of Contents for Gemini

Page 1: ...Temperature Control For Research and Industry Gemini User s Manual ...

Page 2: ...POSE IN NO EVENT SHALL J KEM SCIENTIFIC INC BE LIABLE FOR CONSEQUENTIAL INCIDENTAL OR SPECIAL DAMAGES THE BUYER S SOLE REMEDY FOR ANY BREACH OF THIS AGREEMENT BY J KEM SCIENTIFIC INC OR ANY BREACH OF ANY WARRANTY BY J KEM SCIENTIFIC INC SHALL NOT EXCEED THE PURCHASE PRICE PAID BY THE PURCHASER TO J KEM SCIENTIFIC INC FOR THE UNIT OR UNITS OF EQUIPMENT DIRECTLY AFFECTED BY SUCH BREACH Service J KEM...

Page 3: ...ing Profile 19 3 9 Do s and Don ts When Using Your Controller 20 3 10 Resetting the Controller for use With Heating Mantles 21 3 11 Changing the Temperature Display Resolution 21 3 12 Changing Between PID and ON OFF Operating Modes 22 3 13 Troubleshooting 23 4 APPLICATION NOTES 25 4 1 Theory of How the Controller Works Simply 25 4 2 Controlling a Heating Mantle Temperature Directly 26 4 3 Automati...

Page 4: ... is heating too slowly or you need more power e g heating to high temperatures give the heater more power by turning the power level up one setting If the a solid state variac Volume ranges are printed above this switch as a guide to select the correct power level since it s easier to guess the volume being heated than the appropriate percent power to apply to a heater Heat Off turns off the heate...

Page 5: ...nd Low Safety temperature alarms KEM Net is free of charge and can be downloaded from J KEM s web site 1 Go to J KEM s web site at http www jkem com then click on the Download Software link at the bottom of the home page From the list of software downloads click on KEM Net A popup window appears presenting the options of RUN SAVE and CANCEL Selecting the SAVE option brings up a Save File Dialog wi...

Page 6: ...d the tuning parameters Every type of heater has its own unique set of tuning parameters For the controller to heat with stability it must have programmed with the tuning parameters for the heater currently being used Prior to shipment tuning parameters were programmed into the controller that maximize heating performance for laboratory heating mantles since these are the most common heaters used ...

Page 7: ...e equipment up in the exact configuration it will be used For example to tune to a vacuum oven place the thermocouple in the room temperature oven and plug the oven into the controller If the oven or heater has its own thermostat or power control turn both as high as they ll go 2 Set the controller to the appropriate power level see Section 3 6 If tuning Channel 1 make sure the timer switch is set...

Page 8: ...high as they ll go With this procedure it s not necessary for the equipment to start at room temperature This procedure can be performed at any time and any temperature 2 Set the controller to the appropriate power level see Section 3 6 If tuning Channel 1 make sure the timer switch is set so that heating is on see Section 3 5 Turn the controller and heater on then enter the desired set point temp...

Page 9: ... tuning parameters have been changed or the controller has been autotuned and you want to go back to using heating mantles J KEM recommends that the tuning parameters for heating mantles be loaded manually i e don t autotune to the heating mantle by following the step by step instructions given in Procedure 4 of Section 3 10 2 4 Sensor Placement Placement of the sensor is basically common sense Th...

Page 10: ...ing mode of the timer See Section 3 5 for timer operation instructions 8 Channel 1 Power Outlet Plug only 120 VAC devices into this outlet see Section 3 2 9 Channel 1 Temperature Sensor Input Use the same type of sensor probe as the sensor plug installed on the controller see Section 3 7 The correct sensor type will have the same color plug as the input 9 on the front of the controller 10 Channel ...

Page 11: ...Soak Power Off The controller is shipped with the Ramp to Setpoint feature OFF the user must specifically turn Ramp to Setpoint ON When Ramp to Setpoint is OFF the controller heats to the entered setpoint at the fastest rate possible When Ramp to Setpoint is ON the controller heats at the user entered ramp rate The Ramp to Setpoint feature and its associated parameters are turned on and set in the...

Page 12: ...g Programming the Ramp to Setpoint Feature 1 Press and hold in both the and keys on the front of the temperature meter until the word tunE appears in the display then release both keys 2 Press the key 8 times until the word SPrr appears in the display This is were you set the ramp rate in units of degrees hour First hold in the key then while holding in the key press the and keys until the desired...

Page 13: ...key until SP2 A is showing in the display 5 Hold in the key while holding in the key press the key until nonE is showing in the display then let go of all the keys 6 Press the key until LEVL is showing in the display 7 Hold in the key while holding in the key press the key until 3 is showing in the display then let go of all the keys 8 Press the key until rEU d is showing in the display 9 Hold in ...

Page 14: ...ts three normal states of On toFF and t on If the Power Reduction Circuit Section 3 6 is set to the Heat Off position the timer window always displays oFF The four states of the timer circuit are explained below In the off state no power is applied to the heater even if the temperature meter calls for power to be applied The controller always enters the off state when power is turned on or followi...

Page 15: ...n the timer rolls over from 00 to 59 minutes when entering minutes or from 00 to 99 hours when entering hours Push knob for 1 4 second Push knob for 1 4 second Push knob for 1 4 second Push knob for 1 4 second Hold in knob for 1 second Enter Minutes Function Change Push knob for 1 4 second Function Change Program Change Function Change Function Change Function Change Hold in knob for 1 second Prog...

Page 16: ...ber of minutes rotate the timer knob to the left Rotate knob to enter minutes Step 3 To change the number of hours in the display momentarily press the timer knob 1 4 second and the hours digits begin to blink To increase the number of hours rotate the timer knob to the right To decrease the number of hours rotate the timer knob to the left Rotate knob to enter hours Momentarily push knob to lock ...

Page 17: ... for 1 second to enter the time and start the timer When the timer starts the LED under the label ON at Zero lights This indicates that power to the heater will turn ON when the timer counts down to zero Hold in timer knob for 1 second to store time and start timer At any time the timer program can be aborted by holding in the timer knob for 1 second When this is done the display changes to t on T...

Page 18: ...ask 1 L heating mantle SP 80o C 10 100 ml 10 power When the heating mantle size is substantially larger 5X than the volume being heated i e the heating mantle has excess heating capacity for the volume being heated a lower power setting gives better control 150 ml toluene 250 ml flask 250 ml heating mantle SP 35o C 10 100 ml 10 power Even though the solvent volume isn t included in this power sett...

Page 19: ...tory oven o Power Setting 50 500 ml Power Setting 2L Conditions Set point 45 C HPLC Column wrapped with heating tape Power Setting 50 500 ml o Temp C o Time min 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 Temp o C Time min Power Setting 10 100 ml i e 10 power Power Setting 50 500 ml i e 25 power Power Setting 300 ml 2 L i e 50 power Conditions Set point 70o C 50 ml Toluene 100 ml Round bottomed fl...

Page 20: ... loop should not be broken at any point Don t remove either the thermocouple or heater from the solution without setting the power level to the Heat Off With the thermocouple or heater separated from the solution as the thermocouple cools the controller turns the heater on Since this heat is never fed back to the controller it heats continuously Don t use the controller to regulate an exothermic p...

Page 21: ...n while holding in the key press the or key until the value 3 0 appears in the display then let go of all the keys 6 Press the key once and the word CyC t will appear in the display First hold in the key then while holding in the key press the or key until the value 30 appears in the display then let go of all the keys 7 Press and hold in both the or keys until the temperature appears in the displ...

Page 22: ...ained precisely The advantage of PID mode is that it delivers stable temperature control with any heater from heat lamps to vacuum ovens The disadvantage is that the controller must be properly tuned to the heater being used whereas ON OFF mode requires no tuning Since both heating modes have their advantages simplicity vs accuracy instructions to change the controller to ON OFF mode are given bel...

Page 23: ...er The controller comes on but does not heat The timer controls are set incorrectly Change the position of switch 18 or enter a time into the timer See Section 3 5 The heater is broken To verify that the controller is functioning properly place the power level switch on the 2L setting and enter a set point of 100o C Plug a light into the outlet of the controller then wait 1 minute If the light com...

Page 24: ...mocouple Temperature display offset needed To enter a controller display offset 1 Turn on controller Allow to warm up for 30 minutes 2 Record displayed temperature 3 Press both the and keys on the front of the temperature meter for the channel you want to change until tunE appears then let go of the keys 4 Press the key until LEVL appears 5 First hold in the key then while holding in the key press...

Page 25: ...a closed loop feedback system If the process temperature is below the set point the controller turns the heating mantle on and then monitors the temperature rise of the solution If a small rise results indicating a large volume is being heated the controller sets internal parameters appropriate for heating large volumes If a large rise in temperature results the controller responds by loading a se...

Page 26: ...ing the latent heat of the burner to raise the water temperature from 60o to 80o C This calculation is done by the controller and is independent of the operator The next feature of the controller is directly under operator control and has a major impact on the amount of overshoot on initial warm up 2 Again referring to the range analogy you d obtain better control when heating small volumes if the...

Page 27: ...r the routine is started and cleared by turning the controller off This procedure must be started every time you want to record temperatures Procedure to Start Temperature Logging 1 Press and hold in both the or keys on the front of the temperature meter for the channel you want to change until the word tunE appears in the display then release both keys 2 Press the key once and the word LEUL appea...

Page 28: ...r using an oil bath is that a small volume is being heated and you want to use your 200 Series controller for the job you have a second option J KEM sells heating mantles for small volumes 5 10 25 50 ml which can be plugged directly into the temperature controller Your controller regulates volumes as small as 1 ml in a 5 ml flask using a 5 ml heating mantle If you need to heat even smaller volumes...

Page 29: ...ompared to water since the coefficient of heat for hexane is 0 54 calories g o C and water is 1 0 calorie gram o C That means that 1000 watt seconds of input power will raise the temperature of 10 g of hexane 44o C while the same amount of power causes a 24o C rise in water In theory the tuning constants needed to heat hexane are different from those to heat water Fortunately your J KEM controller...

Page 30: ...nd unit will appear in the display Next hold in the key then while holding in the key press the key until the value o C appears in the display Let go of all the keys 6 Press the key once and the word SP1 d appears in the display Next hold in the key then while holding in the key press the key until the value SSd appears in the display Let go of all the keys 7 Press in both the and keys until the t...

Page 31: ...ll the keys 23 Press the key until ZEro appears in the display Next hold in the key then while holding in the key press the or key until the correct value see below appears in the display Let go of all the keys If the TOP meter is being reset enter the value ___________ If the BOTTOM meter is being reset enter the value ___________ 24 Press the key until the word LEVL appears in the display If you...

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