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3.2

Heater Restrictions.    The heating outlets (10) deliver 15 amps of current at 120 VAC into resistive 
loads (heating mantles, hot plates, ovens, etc.).  Use only resistive loads that are safely operated at 120 
VAC and require less than 15 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 
will become a fire hazard
 (to use oil baths, request application note AN1 or download it 
from http:/www.jkem.com).

Devices other than resistive loads can be plugged into the heating outlets but certain 
restrictions apply.

Device Type

Restrictions

Comments

Incandescent lamps
Infrared heaters

 1200 watts

Set the power reduction circuit 
to the > 2 L position.

Inductive loads:
 * solenoids
 * transformers
 * motors

 6 amps; 720 watts

 1/3 horsepower

The controller must be
programmed for this use. 
Request application note AN5.

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.

Examples of Program Ramps

.

Setpoint

T

em

pe

ra

tu

re

Time

Ramp

Soak

Power Off

Setpoint

T

em

pe

ra

tu

re

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 desired rate of heating (cooling).  Note, this parameter specifies the desired rate of 
heating (cooling), but in cases of extremely high ramp rates the reaction will not actually heat faster than 
the power of the heater will allow.

12

Summary of Contents for 250

Page 1: ...Temperature Control for Research and Industry Model 250 Temperature Controller User Manual...

Page 2: ...2...

Page 3: ...OSE 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 A...

Page 4: ...ts When Using Your Controller 16 3 9 Resetting the Controller for Use With Heating Mantles 17 3 10 Changing the Temperature Display Resolution 17 3 11 Changing between PID and ON OFF Operating Modes...

Page 5: ...e volume of solution being heated not the size of the flask being used The power level switch can be thought of as a solid state variac Volume ranges are printed above this switch as a guide to select...

Page 6: ...ntrols and data logs up to 16 controllers simultaneously Until KEM Net is available J KEM is offering KEM Log at no charge KEM Log provides remote control and data logging for one J KEM controller KEM...

Page 7: ...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 programme...

Page 8: ...ct on the cooling outlet 1 Set the 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 in...

Page 9: ...heater has its own thermostat or power controls turn both as 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...

Page 10: ...ning 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 manual...

Page 11: ...e same color plug as the thermocouple input 6 on the front of the controller 7 Controller On Off switch For maximum display accuracy turn on the controller 30 minutes prior to use WARNING Due to the n...

Page 12: ...feature of J KEM s controllers called Ramp To Setpoint allows you to enter a specific heating rate e g heat to 120o C at a rate of 5o C Hour a second feature called Soak then lets you specify how long...

Page 13: ...he 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...

Page 14: ...or message inPt FAiL blinks in the temperature meter display and the controller stops heating 3 6 Power Reduction Circuit This circuit 8 is the interface to J KEM s patented power control computer whi...

Page 15: ...volume isn t included in this power setting it should be used because low temperatures are better regulated with less power Avoid switching between power levels while the controller is heating Specifi...

Page 16: ...Conditions Set point 70o C 50 ml Toluene 100 ml Round bottomed flask Graph 1 This graph shows typical heating profiles for a laboratory oven and an HPLC column In the example of the oven the heating c...

Page 17: ...oop 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 th...

Page 18: ...ey 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 i...

Page 19: ...hat 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 t...

Page 20: ...n the display tunE FAiL Autotune routine failed Turn off controller for 10 seconds See Section 2 2 Displayed temperature is incorrect Note Type J The controller has not warmed up The display temperatu...

Page 21: ...ing 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 set of para...

Page 22: ...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 range had mor...

Page 23: ...y after 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 ho...

Page 24: ...he controller may need to be autotuned for the oil bath see User s Manual but this is discouraged unless you ll be using the oil bath frequently 2 If the reason for using an oil bath is that a small v...

Page 25: ...ed to water since the coefficient of heat for hexane is 0 54 calories g o C and water is0 1 0 calorie gram o C That means that 1000 watt seconds of input power will raise the temperature of 10 g of he...

Page 26: ...ay Let go of all the keys 10 Press the key once and the word int t will appear in the display Next hold in the key then while holding in the key press the key until the value 10 appears in the display...

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