Configuration Example of Temperature Control

Configuration Example of Temperature Control
REFERENCE
INFORMATION
Configuration Example of Temperature Control
The following is an example of the configuration of temperature control.
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•
•
Relay output
Voltage output
Current output
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•
•
SSR
Cycle controller
Power controller
Controlled object
Temperature
Controller
Control signal
•
•
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Thermocouple
Platinum resistance thermometer
Thermistor
Infrared non-contact sensor
Controller
Temperature Sensor
The Temperature Sensor consists
of an element protected with a
pipe. Locate the element, which
converts temperatures into electric
signals, in places where
temperature control is required.
Electronic Temperature Controller
The Electronic Temperature Controller
is a product that receives electric signal
input from the temperature sensor,
compares the electric signal input with
the set point, and outputs adjustment
signals to the Controller.
Controller
The Controller is used to heat up or
cool down furnaces and tubs using a
device, such as a solenoid or fuel valve,
to switch electric currents supplied to
heaters or coolers.
Temperature Control
Temperature
1. The temperature stabilizes after
overshooting several times.
Time
2. Proper response
Temperature
The set point is input into the Temperature Controller in order to operate the
Temperature Controller. The time
required for stable temperature control
varies with the controlled object. Attempting to shorten the response time will
usually result in the overshooting or
hunting of temperature. When reduce the
overshooting or hunting of temperature,
the response time must not be shortened. There are applications that require
prompt, stable control in the waveform
shown in (1) despite overshooting. There
are other applications that require the
suppression of overshooting in the
waveform shown in (3) despite the long
time required to stabilize temperature. In
other words, the type of temperature
control varies with the application and
purpose. The waveform shown in (2) is
usually considered to be the best one for
standard applications.
Time
Temperature
3. The response is slow in reaching
the set point.
Time
E--2
REFERENCE
INFORMATION
Characteristics of the Controlled Object
Before selecting the Temperature Controller and Temperature Sensor models, it is necessary to understand the thermal characteristics of the
controlled object for proper temperature control.
Heat capacity, which indicates the degree of ease of
heating, varies with the capacity of the furnace.
Static
characteristics
Static characteristics, which indicate the capability of
heating, vary with the capacity of the heater.
Dynamic
characteristics
Dynamic characteristics, which indicate the startup
characteristics (i.e., excessive response) of heating, vary
with the capacities of the heater and furnace that affect
each other in a complex way.
External disturbances are causes of temperature
change. For example, the opening or closing of the door
of a constant temperature oven will be a cause of
external disturbance thus creating a temperature
change.
External
disturbances
J ON/OFF CONTROL
ACTION
J P ACTION
This is the simplest form of electronic
control, usually used in the least expensive controllers. As shown in the graph
below, if the process value is lower than
the set point, the output will be turned
ON and power will be supplied to the
heater. If the process value is higher than
the set point, the output will be turned
OFF with power to the heater shut off.
This control method is called ON/OFF
control action, in which the output is
turned ON and OFF on the basis of the
set point to keep the temperature
constant. In this operation, the temperature is controlled with two values (i.e.,
0% and 100% of the set point). Therefore, the operation is also called twoposition control action.
Characteristics of
ON/OFF control action
Hysteresis
Set
point
For more stable control, it is necessary to
slow down the rate of temperature rise
when approaching the set point in order
to avoid overshoot. By modifying the
ON/OFF switching pattern, the peaks
and troughs are smoothed out, thus
maintaining a stable temperature. P
action (or proportional control action) is
used for obtaining the output in proportion to the input.
The Temperature Controller in P action
has a proportional band with the set point
in the proportional band. The control
output varies in proportion to the deviation in the proportional band. In normal
operation, a 100% control output will be
ON if the process value is lower than the
proportional band. The control output will
be decreased gradually in proportion to
the deviation if the process value is
within the proportional band, and a 50%
control output will be ON if the set point
coincides with the process value (i.e.,
there is no deviation). This means P
action ensures smooth control with
minimal hunting compared with the
ON/OFF control action.
Time
A narrow proportional
band is set.
A wide proportional
band is set.
Set point
A narrow proportional
band is set.
Set
point
Control output
Heater
Proportional
control action
Example:
If a Temperature Controller with a temperature range of 0° to 400°C has a 5%
proportional band, the width of the proportional band will be converted into a
temperature range of 20°C. In this case,
provided that the set point is 100°C, a full
output is kept turned ON until the process value reaches 90°C, and the output
is OFF periodically when the process
value exceeds 90°C. When the process
value is 100°C, there will be no difference in time between the ON period and
the OFF period (i.e., the output is turned
ON and OFF with the same interval).
Control output
Characteristics of
controlled object
Heat capacity
Offset
A wide proportional
band is set.
Time
Temperature
Set
point
Proportional band
E--3
REFERENCE
INFORMATION
J I ACTION
J ADVANCED PID
CONTROL
External
disturbance
P (proportional
control) action
only
Time
Control output
I action (integral control action or reset)
helps to achieve control at the set point
and is used for obtaining the output in
proportion to the time integral value of
the input.
P action causes an offset. Therefore, if
proportional control action and integral
control action are used in combination,
the offset will be reduced as the time
goes by until finally the control temperature will coincide with the set point and
the offset will cease to exist.
Set point
PD (proportional
and derivative
control) action
A long derivative time is set.
A short derivative time is set.
Set point
Offset ceases
to exist.
Offset
Time
PI (proportional
and integral
control) action
A long derivative time is set.
P (proportional
control) action
only
Set
point
A short derivative time is set.
Time
Conventional PID control uses a single
control block to control the responses of
the Temperature Controller to a target
value and external disturbances. Therefore, the response to the target value will
oscillate due to overshooting if importance is attached to the response to external disturbances with the P and I parameters set to small values and the D
parameter set to a large value in the control block. On the other hand, if importance is attached to the response to the
target value (i.e., the P and I parameters
are set to large values), the Temperature
Controller will not be able to respond to
external disturbances quickly. It will be
impossible to satisfy both the types of
responses in this case.
Advanced PID control eliminates this
weakness while retaining the strengths of
PID control, thus making it possible to
improve both types of responses.
PID Control
Control output
Time
J PID CONTROL
A short integral time is set.
A long integral time is set.
Time
A short integral time is set.
Set
point
PID control is a combination of proportional, integral, and derivative control
actions, in which the temperature is
controlled smoothly by proportional
control action without hunting, automatic
offset adjustment is made by integral
control action, and quick response to an
external disturbance is made possible by
derivative control action.
Response to the target value will become
slow if response to the external disturbance is improved.
Response to the external disturbance will
become slow if response to the target value is improved.
A long integral time is set.
Advanced PID Control
Time
J D ACTION
D action (derivative or rate control action)
is used for obtaining the output in proportion to the time derivative value of the
input. It provides a sudden shift in output
level as a result of a rapid change in actual temperature.
Proportional control action corrects the
result of control and so does integral
control action. Therefore, proportional
control action and integral control action
respond slowly to temperature change,
which is why derivative control action is
required. Derivative control action corrects the result of control by adding the
control output in proportion to the slope
of temperature change. A large quantity
of control output is added for a radical
external disturbance so that the temperature can be quickly in control.
E--4
PID
control
Response to
target value
Response to
external disturbance
Controls both the target value response
and external disturbance response.
REFERENCE
INFORMATION
J PID WITH FUZZY CONTROL
By adding fuzzy control to PID control,
further improvement in response to external
disturbances is possible. PID and fuzzy
control usually operate as PID control. If
there is external disturbance, fuzzy control
will operate in combination with PID control.
OMRON’s fuzzy control estimates temperature change from the difference between
the deviation (i.e., the difference between
the set point and process value) and
deviation change rate, and then makes the
delicate adjustment of the control output.
PID control
Set
point
External
disturbance
An increase in output.
PID and fuzzy control
Suppresses the
output to eliminate
overshooting.
Control on the basis of the deviation and deviation change rate.
Response to the target value.
Response to external disturbance
PID control
PID and fuzzy control
E--5
REFERENCE
INFORMATION
Topical Reference
J SECTION ORGANIZATION
The following Topical Reference discusses how Omron controls perform in
each critical aspect of a temperature or
process control system. The sections are
divided into these categories, then presented in alphabetic order
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This glossary does not address the many
terms commonly used in general industrial control.
Control
Alarm
Temperature Sensor
Output
Setting
Control
Temperature or
deviation
J ANTI-RESET WINDUP
(ARW) FUNCTION
Set point
Proportional band
Deviation
Time
Integral output
ARW stands for anti-reset windup. This
feature reduces or eliminates excessive
Reset (Integral action) error created in
response to the steep rise to the initial
temperature set point. There is usually a
large deviation (i.e., a large difference
between the process value and set point)
when the Temperature Controller starts
operating. Integral control action in PID
control is repeated until the temperature
reaches the set point. As a result, an
excessive integral output causing
overshooting is output. To prevent this,
the ARW function sets a limit to restrict
the output rise in integral control action.
In normal control operation, the integral
output is eliminated until the process
value reaches the proportional band.
Overshooting due to
excessive integral output.
Initial integral output with
ARW function disabled.
Initial integral
output with ARW
function enabled.
Time
J CONTROL CYCLE AND TIME-PROPORTIONING CONTROL ACTION
Temperature
Set point
The control output will be turned ON intermittently according to a preset cycle if
P action is used with a relay or SSR.
This preset cycle is called control cycle
and this control method is called timeproportioning control action.
Proportional
band
Actual
temperature
The higher the temperature is,
the shorter the ON period is.
T: Control cycle
Control output =
TON
TON + TOFF
x 100 (%)
TON: ON period
TOFF: OFF period
E--6
Example;
If the control cycle is 10 s with an 80%
control output, the ON and OFF periods
will be the following values.
TON: 8 s
TOFF: 2 s
REFERENCE
INFORMATION
J CONTROL OUTPUT
ON/OFF output
Relay output
Contact relay output used for control methods
with comparatively low switching frequencies.
SSR output
Non-contact solid-state relay output for switching
1 A maximum.
Voltage output
ON/OFF pulse output at 5, 12, or 24 VDC
externally connected to a high-capacity SSR.
Current output
Continuous 4- to 20-mA or 0- to 20-mA DC
output used for driving power controllers and
electromagnetic valves. Ideal for high-precision
control.
Voltage output
Continuous 0 to 5 or 0 to 10 VDC output used
for driving pressure controllers. Ideal for
high-precision control.
Control
output
Linear output
E--7
REFERENCE
INFORMATION
Control Output Connection Example Using Voltage Output to Drive SSRs
Electronic Temperature Controller
Load
Voltage output
terminals for
driving SSR
Heater
Load power supply
Directly connectable
Number of SSRs
connectable in parallel
Temperature Controller at 12-VDC
Output with 40 mA
5 (8)
E5jJ
(Excluding E5CJ)
3 (4)
E5jK
(Excluding E5CK)
3 (4)
E5AN, E5EN
Temperature Controller at 12-VDC
Output with 30 mA
1 (2)
Values in parentheses
indicate 400 V models.
8
E5ZE
4
G3PA-VD at 240-V output
with 10, 20, 40, or 60 A
Rated input voltage:
5 to 24 VDC
Subminiature, slim model with a
mono-block construction and
built-in heat sink
G3NH with 75 or 150 A
5 to 24 VDC
4
2
Temperature Controller at 12-VDC
Output with 20 mA
E5CS-X
5 (8)
3 (4)
Ideal for high-power
heater control
G3NA at 240-V output
with 5, 10, 20, or 40 A, at
480 V with 10, 20, or 40 A
5 to 24 VDC
3 (4)
E5CN, E5GN
1 (2)
Standard model with
screw terminals
Values in parentheses
indicate 400 V models.
2
E5CJ
1
E5CK
1
5
Temperature Controller at 5-VDC
Output with 10 mA
E5C4
2
12 VDC
5 VDC
Compact, low-cost model
with tab terminals
G3B with 5 A
5 to 24 VDC
6
3
E--8
G3NE with 5, 10, or 20 A
Fits standard 8-pin round socket,
offers 5 A switching current
REFERENCE
INFORMATION
J DERIVATIVE TIME
Deviation
PD Action and Derivative Time
PD action
(with a short derivative time)
PD action
(with a long derivative
time)
Control output
Derivative time is the period required for
a ramp-type deviation in derivative
control (e.g., the deviation shown in the
graph at right) to coincide with the control
output in proportional control action. The
longer the derivative time is, the stronger
the derivative control action is.
P action
D2 action
(with a short
derivative time)
D1 action
TD: Derivative
time
(with a long derivative time)
J FUZZY SELF-TUNING
PID constants must be determined
according to the controlled object for
proper temperature control. The conventional Temperature Controller incorporates an auto-tuning function to calculate
PID constants, in which case, it will be
necessary to give instructions to the
Temperature Controller to trigger the
auto-tuning function. Furthermore, if the
limit cycle method is adopted, temperature disturbance may result. The Temperature Controller in fuzzy self-tuning
operation determines the start of tuning
and ensures smooth tuning without
disturbing temperature control. In other
words, the fuzzy self-tuning function
makes it possible to adjust PID constants
according to the characteristics of the
controlled object.
Auto-tuning Method of a
Conventional Temperature
Controller
Auto-tuning Function: Automatically
calculates the appropriate PID constant
for controlling objects.
Features:
1. Tuning will be performed when the
AT instruction is given.
2. The limit cycle signal is generated
to oscillate the temperature before
tuning.
Target
value
PID constants are calculated by tuning
at the time of change in the set point.
•
When an external disturbance affects
the process value, the PID constants
will be adjusted and kept in a specified
range.
•
If hunting results, the PID constants will
be adjusted to suppress the hunting.
External
disturbance 1
Target
value
PID gain
calculated.
AT starts.
Temperature
oscillated.
PID gain
calculated.
External
disturbance 2
Temperature
in control
Temperature
in control
ST starts.
AT
instruction
Fuzzy Self-tuning in 3 Modes
•
Self-tuning Function
Self-tuning (ST) Function: A function to
automatically calculate optimum PID
constants for controlled objects.
Features:
1. Whether to perform tuning or not is
determined by the Temperature
Controller.
2. No signal disturbing the process
value is generated.
J HUNTING AND OVERSHOOTING
Hunting and Overshooting in ON/OFF
Control Action
Overshooting
Set point
ON/OFF control action often involves the
waveform shown in the following graph.
A temperature rise in excess of the set
point after temperature control starts is
called overshooting. Temperature oscillation near the set point is called hunting.
Improved temperature control is to be
expected if the degrees of overshooting
and hunting are low.
Hunting
E--9
INFORMATION
J HYSTERESIS
ON/OFF control action turns the output
ON or OFF on the basis of the set point.
This means the output frequently
changes according to minute temperature changes, which shortens the life of
the output relay or unfavorably affects
some devices connected to the Temperature Controller. Therefore, a temperature
band is created between the ON and
OFF operations. This band is called hysteresis.
Example:
If the Temperature Controller with a
temperature range of 0°C to 400°C has a
0.2% hysteresis, D will be 0.8°C.
Therefore if the set point is 100°C, the
output will turn OFF at a process value of
100°C and will turn ON at a process
value of 99.2°C.
Hysteresis
D: Hysteresis
Control output
REFERENCE
Temperature
J INTEGRAL TIME
Deviation
PI action (with a short integral time)
PI action
(with a long integral time)
Control output
Integral time is the period required for a
step-type deviation in integral control
(e.g., the deviation shown in the following
graph) to coincide with the control output
in proportional control action. The shorter
the integral time is, the stronger the integral control action is. If the integral time
is too short, however, hunting may result.
P action
T1: Integral
time
(with a short integral time)
(with a long integral time)
J OFFSET
Offset
Proportional band
Set point
Proportional control action causes an
error in the process value due to the heat
capacity of the controlled object and the
capacity of the heater, which results in a
small discrepancy between the process
value and set point in stable operation.
This error is called offset. Offset is the
difference in temperature between the
set point and the actual process
temperature. Offset may exist above or
below the set point.
Offset
(Applicable Model: E5jS)
The self-tuning function is incorporated
by E5jS Digital Temperature Controller.
The function makes it possible to calculate and use an optimum proportional
band automatically according to change
in the temperature.
Set point
J SELF-TUNING FUNCTION
Time
In self-tuning
operation
E--10
REFERENCE
INFORMATION
J TUNING PID PARAMETERS
All PID process/temperature controllers
require the adjustment of the P, I, D and
other parameters in order to allow
accurate control of the load. If the
controller is not tuned, then it cannot
control the temperature or process
variable of that load with any accuracy.
There have been a variety of conventional methods suggested and implemented to obtain PID constants: The
step response, marginal sensitivity, and
limit cycle methods. In general, the P, I
and D parameters are tuned either
manually or via an auto-tuning technique.
Auto-tuning methods make it possible to
obtain PID constants suitable to a variety
of objects.
Limit Cycle Method
ON/OFF control action starts from the
start point A in this method. Then obtain
the PID constants from the hunting cycle
T and oscillation D.
Manual Tuning
Readjustment of PID Constants
PID constants calculated in auto-tuning
operation normally do not cause problems except for some particular applications, in which case, refer to the following
to readjust the PID constants.
Step Response Method
The value most frequently used must be
the set point in this method. Calculate the
maximum temperature ramp R and the
dead time L from a 100% step-type control output. Then obtain the PID
constants from R and L.
Response to Change in Integral Time
Wider
Set
point
Set point
Oscillation
It is possible to reduce hunting, overshooting, and undershooting although a
comparatively long startup time and set
time will be required.
Hunting cycle
Time
Narrower
Set
point
Auto-Tuning
The process temperature reaches the set
point within a comparatively short time
although overshooting, undershooting,
and hunting will result.
Response to Change in Proportional
Band
Response to Change in Derivative
Time
Set point
Wider
Wider
Set
point
Set
point
It is possible to suppress overshooting
although a comparatively long startup
time and set time will be required.
Time
Set point
Marginal Sensitivity Method
Proportional control action starts from the
start point A in this method. Narrow the
width of the proportional band until the
temperature starts to oscillate. Then obtain the PID constants from the value of
the proportional band and the oscillation
cycle T at that time.
Marginal sensitivity
method
The process value reaches the set point
within a comparatively short time with
comparatively small amounts of overshooting and undershooting although
fine-cycle hunting will result due to the
change in process value.
Narrower
Set
point
Narrower
Set
point
The process value reaches the set point
within a comparatively short time and
keeps the temperature stable although
overshooting and hunting will result until
the temperature becomes stable.
It will take a comparatively long time for
the process value to reach the set point
with heavy overshooting and
undershooting.
Time
PID Control and Tuning Methods
Type of PID control
Model
PID
Advanced PID
Auto-tuning methods
PID with fuzzy control
Step response
Limit cycle
E5jJ
----
Fuzzy self-tuning
----
Built-in
Built-in
E5jK
----
Auto-tuning, Fuzzy self-tuning
----
Built-in
Built-in
E5jN
----
Auto-tuning, Fuzzy self-tuning
----
Built-in
Built-in
E5jS
Self-tuning
----
----
—
—
E5ZE
----
----
Auto-tuning (both PID and
fuzzy parameters)
Not built-in
Built-in
E--11
REFERENCE
INFORMATION
Alarm
J ALARM OPERATION
The Temperature Controller compares
the process value and the preset alarm
value, turns the alarm signal ON, and
displays the type of alarm in the preset
operation mode.
Absolute-value Alarm
Deviation Alarm
The absolute-value alarm turns ON according to the alarm temperature regardless of the set point in the Temperature
Controller.
The deviation alarm turns ON according
to the deviation from the set point in the
Temperature Controller.
Setting example
Alarm temperature is set to 110°C.
Setting Example
Alarm temperature is set to 110°C.
Alarm set
point: 10 °C
Alarm set point
Set point (SV):
100°C
Set point (SV):
100°C
Alarm value:
110°C
The alarm set point in the above example
is set to 110°C.
Alarm value:
110°C
The alarm set point in the above example
is set to 10°C.
(Single-phase use only)
Many types of heaters are used to raise
the temperature of the controlled object.
The CT (Current Transformer) is used by
the Temperature Controller to detect the
heater current. If the heaters’ power
consumption drops, the Temperature
Controller will detect the heater burnout
from the CT and will output the heater
burnout alarm.
Current value
J HEATER BURNOUT ALARM
The wires connected to the
Temperature Controller has no polarity.
Heater burnout alarm
Heater burnout
Current
Transformer
(CT)
Control outpu
Heater current waveform
(CT waveform)
Heater
Switch
J LOOP BURNOUT ALARM (LBA)
Applicable Models: E5jK
The LBA (loop burnout alarm) is a function
to turn the alarm signal ON by assuming
the occurrence of control loop failure if
there is no input change with the control
output set to the highest or lowest value.
Therefore, this function can be used to detect control loop errors.
J STANDBY SEQUENCE ALARM
It may be difficult to keep the process
value outside the specified alarm range
in some cases (e.g., when starting up the
Temperature Controller) and as a result
the alarm turns ON abruptly. This can be
prevented with the standby sequential
function of the Temperature Controller.
This function makes it possible to ignore
the process value right after the Temperature Controller is turned on or right after
the Temperature Controller starts temperature control. In this case, the alarm
will turn ON if the process value enters
the alarm range after the process value
has been once stabilized.
E--12
Example of Alarm Output with Standby Sequence Set
Temperature Rise
Upper-limit
alarm set
Set point
Temperature Drop
Upper limit
alarm set
Set point
Lower-limit
alarm set
Alarm
output
Lower limit
alarm set
Alarm
output
REFERENCE
INFORMATION
J ALARM SELECTIONS AVAILABLE BY CONTROLLER SERIES
Alarm type
yp
Alarm output operation
When X is positive
Upper- and
lower-limit
(deviation)
Process/Temperature Controller series
When X is negative
K3TL,
K3NH
E5CSX
E5AN,
E5EN,
E5CN,
E5GN
E5AK,
E5EK,
E5CK
E5jK
-T,
E5EKDRT
E5AJ,
E5EJ,
E5CJ
E5ZE
X
X
X
X
X
X
*2
Upper-limit
(deviation)
X
X
X
X
X
X
X
Lower-limit
(deviation)
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Upper-limit with
standby
sequence
(deviation)
X
X
X
X
X
Lower-limit with
standby
sequence
(deviation)
X
X
X
X
X
Absolute-value
upper-limit
X
X
X
X
X
X
Absolute-value
lower-limit
X
X
X
X
X
Absolute-value
upper-limit with
standby
sequence
X
X
X
Absolute-value
lower-limit with
standby
sequence
X
X
X
E5AK
and
E5EK
only
E5AKT and
E5EKT only
X
X
Upper- and
lower-limit range
(deviation)
Upper- and
lower-limit with
standby
sequence
(deviation)
Heater burnout
detection alarm
(uses a current
transformer input)
*3
*5
*4
E--13
REFERENCE
INFORMATION
Temperature Sensor
J COLD JUNCTION EFFECT
Thermocouples only give an accurate
reading if the “cold” end of the device,
which is connected to the terminals on a
controller, is maintained at 0°C. Since
this is not practical in industrial applications, controllers are calibrated at a
reference temperature, usually 20°C to
25°C, and an allowance made for the
“cold junction” error. A sensor (usually a
semiconductor) built into the controller,
then monitors any changes in this “cold
junction,” and the controller automatically
compensates for these changes (this is
called “cold junction compensation”). For
this reason, thermocouple leads should
always be connected directly to the
controller terminals. If the leads are too
short, they may be lengthened by the
use of special compensating cable or
thermocouple extension wire that
matches the thermocouple type.
Terminal
Temperature
Controller
The thermo-electromotive force VT is
calculated from the following formula:
VT = K (350 -- 20)
Condition:
The terminal temperature is 20°C.
VT = K (350 -- 20) + K S 20 = K S 350
Thermo-electromotive force
of thermocouple
Sensing
point
350°C
Thermo-electromotive force
generated by cold junction
compensating circuit
Cold junction
compensating circuit
J COMPENSATING CONDUCTOR
Compensating
conductor
Connection
terminal
Terminal
An actual application may have a
sensing point located far away from the
Temperature Controller. Specialconductor thermocouples are expensive.
Therefore, the compensating conductor
is connected to the thermocouple in such
a case. The compensating conductor
must be in conformity with the
characteristics of the thermocouple,
otherwise precise temperature sensing
will not be possible.
Example of Compensating Conductor
Use
K (350 -- 30) + K (30 -- 20) +K S 20 + K S 350
Temperature
Controller
Thermo-electromotive
force of thermocouple
Thermo-electromotive force
generated by cold junction
compensating circuit
Thermo-electromotive force through
compensating conductor
J HOT JUNCTION AND COLD JUNCTION
A thermocouple has a hot junction and
cold junction. The hot junction is for temperature sensing and the cold junction is
connected to the Temperature Controller.
Metal A
Hot
junction
Metal B
J INPUT COMPENSATION
A preset point is added to or subtracted
from the temperature detected by the
temperature sensor of the Temperature
Controller to display the process value.
The difference between the detected
temperature and displayed temperature
is set as an input compensation value.
Furnace
Input compensation value: 10°C
(Displayed value is 120°C)
(120 -- 110 = 10)
E--14
Cold
(reference
junction
(0°C)
REFERENCE
INFORMATION
J PLATINUM RESISTANCE THERMOMETER (RTD)
The resistance of a metal will increase as
the temperature of the metal increases.
Platinum is especially responsive to
temperature changes. RTD’s are usually
made of fine platinum wire wrapped
around a mica or ceramic plate, then
encased in a stainless steel tube.
Three-wire Resistance Thermometer
Omron’s temperature/process controllers
accept three-wire platinum resistance
thermometer sensors. One of the conductors is connected to two wires and
the other resistance conductor is connected to another wire, the wiring of
which eliminates the influence of resistance from the extended lead wires.
Connection of Three-wire Platinum
Resistance Thermometer
Platinum resistance thermometer
Temperature
Controller
J SET POINT (SP) RAMP
The SP ramp function controls the target
value change rate with the variation
factor. Therefore, when the SP ramp
function is enabled, some range of the
target value will be controlled if the
change rate exceeds the variation factor
as shown at right.
Target
value
after
changing
Target
value
before
changing
SP ramp
SP ramp
set value
SP ramp
time unit
Change
point
Time
J THERMISTORS
These are temperature sensitive semiconductors, usually encased in a glass
bead. For industrial applications, this
would be housed in a stainless steel tube
in common with the other forms of sensors described here.
Their main advantage lies in the large
change of resistance with temperature
compared with other forms of RTD, and
of course there is no cold junction effect.
The main disadvantage of thermistors is
that the characteristic is particularly non-
linear, making them a reasonable choice
only where they are required for control
over a very limited temperature band; for
example, the control of photographic
chemical solution temperatures.
at the unheated ends of the wires, and is
the signal used by the controller to
determine the actual temperature. The
most commonly used thermocouples are
Iron/Constantan construction (known as
Type J) and Nickel-chromium/
Nickel-aluminum construction (known as
Type K).
J THERMOCOUPLE
A thermocouple consists of two different
metal wires with the ends connected
together. When this assembly is heated,
a very small voltage, which is
proportional to the temperature, appears
E--15
REFERENCE
INFORMATION
Output
J HEATING AND COOLING CONTROL
Two control outputs (one for heating and
one for cooling) can be provided by a
temperature controller. The relation between these two control outputs is expressed by the V-shaped portion of the
diagram. As shown, the two outputs may
be overlapped, or there may be a dead
band between the two.
Temperature
Controller in
heating and
cooling
control
Heating and Cooling Outputs
Heating
Cooling
Controlled
object
Heating
output
Cooling
output
Heating
output
Set point
Cooling
output
Set point
The Temperature Controller in normal
operation will increase control output if
the process value is higher than the set
point (i.e., if the Temperature Controller
has a positive deviation).
Control output (%)
J NORMAL OPERATION
Set point
Low
High
J POSITION-PROPORTIONING CONTROL
This control is also called ON/OFF servo
control. In this control system, the temperature and the degree of opening
(position) of the control valve are fed
back to the temperature controller.
J REVERSE OPERATION
Temperature Controller in
position-proportioning control.
Control output (%)
The Temperature Controller in reverse
operation will increase control output if
the process value is lower than the set
point (i.e., if the Temperature Controller
has a negative deviation).
Open
Controlled
object
Close
Low
Set point
Potentiometer
reading valve
opening.
High
J TRANSMISSION OUTPUT
E--16
tween the upper and lower limits will be
turned ON if the E5CK-jF is used.
Transmission output
A Temperature Controller with current
output independent from control output is
available. The process value or set point
within the available temperature range of
the Temperature Controller is converted
into 4- to 20-mA linear output that can be
input into recorders to keep the results of
temperature control on record. If the
Temperature Controller is the E5AX-AF
that has a set limit value, the output will
turn ON within the set limit value. The
upper and lower limits can be set for
transmission output in the E5CK-jF.
Therefore, the transmission output be-
Temperature
Controller with
transmission
output
Recorder
Temperature sensor
Process value
Lower limit
Upper limit
Possible setting range
REFERENCE
INFORMATION
Setting
J MULTIPLE SET POINTS
Two or more set points independent from
each other can be set in the Temperature
Controller in control operation.
J SET LIMIT
The set point range depends on the temperature sensor and the set limit is used to
restrict the set point range. This restriction
affects the transmission output of the Temperature Controller.
Possible setting range
J SETTING MEMORY BANKS
The Temperature Controller stores a maximum of eight groups of data (e.g., set value
and PID constant data) in built-in memory
banks for temperature control. The Temperature Controller selects one of these
banks in actual control operation.
Memory Bank 0
Set value
P constant
I constant
D constant
:
:
:
Bank 1
Bank 7
Bank 1 is selected.
Temperature
control with
data in memory
bank 1.
J SHIFT SET OPERATION
The set point can be shifted to a different
value to be used by the Temperature Controller in shift set operation.
Set temperature: 200°C
Shift set point: --50°C
Set point:
--150°C
Shift set operation
E--17
REFERENCE
INFORMATION
DeviceNett Overview
J WHAT IS THE DEVICENET?
DeviceNet is a low-cost communications
link to connect industrial devices to a network and eliminate expensive hardwiring.
Typical devices include limit switches,
photoelectric sensors, valve manifolds,
motor starters, process sensors, bar
code readers, variable frequency drives,
panel displays and operator interfaces.
The direct connectivity provides improved communication between devices
as well as important device-level diagnostics not easily accessible or available
through hardwired I/O interfaces.
DeviceNet is a simple, networking
solution that reduces the cost and time to
wire and install industrial automation
devices, while providing interchangeability of “like” components from multiple
vendors.
J DEVICENET FEATURES AND FUNCTIONALITY
Network size
Up to 64 nodes
Network length
g
Selectable end-to-end network distance varies with speed
Baud rate
Distance
125 Kbps
500 m (1,640 ft)
250 Kbps
250 m (820 ft)
500 Kbps
100 m (328 ft)
Data packets
0 to 8 bytes
Bus topology
Linear (trunk line/drop line); power and signal on the same network
cable
Bus addressing
Peer-to-peer with multi-cast (one-to-many);
Multi-master and Master/Slave special case;
polled or change-of-state (exception-based)
System features
Removal and replacement of devices from the network under power.
J DEVICENET PHYSICAL LAYER AND MEDIA
Chapter 9, Volume 1 in the DeviceNet
Specifications defines the allowable topologies and components. The variety of
topologies that are possible are shown in
the figure below. The specification also
deals with system grounding, mixing
thick and thin media, termination, and
power distribution.
The basic trunk line-drop line topology
provides separate twisted pair busses for
both signal and power distribution. Thick
or thin cable can be used for either trunk
lines or drop lines. End-to-end network
distance varies with data rate and cable
size.
Devices can be powered directly from
the bus and communicate with each other using the same cable. Nodes can be
removed or inserted from the network
without powering-down the network.
Terminator
Node
Power taps can be added at any point in
the network which makes redundant
power supplies possible. The trunk line
current rating is 8 amps. An opto-isolated
design option allows externally powered
devices (e.g., AS drives starters and solenoid valves) to share the same bus
cable. Other CAN-based networks allow
only a single power supply (if at all) for
the entire network.
Tap
Terminator
Node
Drop line
Node
Node
Node
Node
Node
Node
Node
Node
Zero drop
E--18
Node
Short drops
Node
Node
REFERENCE
INFORMATION
Control Period and Manipulated Variable
All time proportional controls have a control period or a similarly named parameter. The parameter, regardless of its name, behaves the
same way in each control
A control period (CP) is the maximum amount of time that the output is on. The CP is defined by the controller’s algorithm. Long CP’s
work better for slower processes, e.g., a temperature change of one degree or less per minute. Shorter CP’s work better for faster rates of
change such as several degrees per second.
The Manipulated Variable (MV) also control the output within the limits of the CP. The MV is sometimes referred to by other names by
some manufacturers. These names include control output, percentage output, and manipulated output. The MV is the percentage of output power that the algorithm uses to control the output. For example, if the algorithm specifies a CP of 20 seconds and an MV of 50%, the
output will be on for a total of 10 seconds (see illustration below). Note that the output would not be ON for 10 consecutive seconds.
CP = 20 (Omron default)
MV = 50%
What would happen in an ideal situation is that the output would trigger ON and OFF throughout the entire 20 seconds, so that at the end
of the 20 seconds, the TOTAL TIME ON would be 10 seconds.
Changing the MV would change the TOTAL TIME ON. For example, with the same CP of 20 and an MV of 75%, the TOTAL TIME ON
would be 15 seconds. As in the previous example, the output would not be on for 15 consecutive seconds.
A 5-second control period allows the MV to have the shortest possible ON time. One percent of 5 seconds is 0.05 seconds or 50 ms.
Therefore, 50 ms is the minimum ON time.
Different types of processes require different CP’s. If you are controlling a slow-moving process, a long CP allows time for the process to
react to the controller’s output signal. However, for a faster moving process, if the output stays on too long, the process variable (e.g.
temperature) exceeds the set point. The controller would then try to readjust itself by shutting off the output, but because the CP is too
large, the output stays off too long and the PV undershoots the set point. The only way to correct this type of hunting is to shorten the CP
of the controller.
E--19
REFERENCE
INFORMATION
Manual Tuning of PID Values
When PID values should be adjusted manually, refer to the following:
J PID (P) CONTROL ACTION
Offset occurs when the proportional band is large, but the possibility of
overshooting is less likely. On the contrary, when the proportional band is
small, overshooting occurs and the control waveform becomes an ON/OFF
control (the occurrence of hunting).
Tuning adjustment:
D
Generally, the proportional band should be adjusted from a larger to
smaller value.
D
When there is gentle hunting, the hunting can be made smaller by
making the proportional band wider.
J INTEGRAL (I) ACTION
Integral action is performed to diminish the offset caused by proportional control
in proportion to the elapsed time. When too short of an integral time is set to
eliminate offset, integral action becomes stronger and it may cause hunting.
Tuning adjustment:
D
Generally, integral time should be adjusted from a longer to shorter time.
D
When there is gentle hunting or repetition of overshooting, too strong of an
integral action is suspected in many cases. Hunting can become smaller if
a longer time is set. (It is also possible to make integral action weaker by
making the proportional band wider.)
J DERIVATIVE (D) ACTION
Derivative action obtains the original control status as soon as possible by
giving a large quantity of the manipulated variable for rapid external
disturbance. When a longer derivative time is set, the control is disturbed since
the large quantity of the manipulated variable is continuously working. (Usually
hunting occurs in shorter periods than the hunting caused by inappropriate
proportional band and integral time.)
Tuning adjustment:
D
Generally, derivative time should be adjusted from a shorter to longer time.
D
When hunting occurs in a short period, early response of the control
system and too strong derivative action are suspected. Shorten the
derivative time.
E--20
REFERENCE
INFORMATION
Glossary
Adaptive Tuning
Cold Junction Compensation
Used to continuously monitor and
optimize PID constants while the
controller operates. Three tuning
algorithms are used to recalculate the
PID constants within 500 ms after the
process value stabilizes at set point:
Step-response method, disturbance
tuning and hunting tuning
Electronic means of compensating for
the ambient temperature at the cold
junction of a thermocouple so it
maintains a reference to 0°C.
Anti-reset Wind-up (ARW)
A feature of PID controllers that prevents
the integral (auto-reset) circuit from
operating when the temperature is
outside the proportional band.
Alpha (α)
This represents the temperature
coefficient of the change in electrical
resistance of a material. For each °C in
temperature the electrical resistance
changes. It is the defining parameter for
platinum resistance temperature
detectors (RTD sensors). The unit of
measure is ohms/ohms/°C.
Analog
Data collected and represented by
continuously variable quantities, such as
voltage measurement or temperature
variation.
Contact Output
Relay control outputs are often available
in these contact forms:
Form A Contact (SPST-NO)
Single-pole, single-throw relays use the
normally open and common contacts to
switch power. The contacts close when
the relay coil is energized and open
when power is removed from the coil.
Form B Contact (SPST-NC)
Single-pole, single-throw relays use the
normally closed and common contacts.
These contacts open when the relay coil
is energized and close when power is
removed from the coil.
Form C Contact (SPDT)
Single-pole, double-throw relays use the
normally open, normally closed and
common contacts. The relay can be
wired as a Form A or Form B contact.
Control Action
A continuously variable signal that is
used to represent a value, such as the
process value or set point value. Typical
ranges include 4 to 20 mA, 0 to 20 mA, 1
to 5 VDC, and 0 to 5 VDC.
The control output response relative to
the difference between the process
variable and the set point. For reverse
action (usually heating), as the process
decreases below the set point, the output
increases. For direct action (usually
cooling), as the process increases above
the set point, the output increases.
Auto-tuning
Control Mode
This feature automatically calculates
then resets the PID values based on
temperature control performance over a
sampled period. In some of Omron’s
controllers, auto-tuning also optimizes
the settings for fuzzy logic control values.
The type of control action used by the
controller can include ON/OFF,
time-proportioning, PD, and PID. Other
combinations and refinements are used.
Analog Output
Burnout Function
An action to release the output when the
thermocouple has burned out, platinum
RTD develops an open or short, or
infrared problems occur.
CE
A marking on products that comply with
European Union requirements pertaining
to safety and electromagnetic
compatibility.
Celsius
A temperature scale in which water
freezes at 0°C and boils at 100°C at
standard atmospheric pressure. The
formula to convert Fahrenheit
temperatures to Celsius is as follows:
°F = (1.8 x °C) + 32.
CSA
Canadian Standards Association is an
independent testing laboratory that
establishes commercial and industrial
standards, as well as tests products and
certifies them.
C-UL
This symbol appearing in literature and
marked on products indicates Canadian
recognition of Underwriters Laboratories,
Inc. approval of particular product
classes. The C-UL approval may stand in
place of Canadian Standards Association
certification. All references to C-UL are
based on prior listing or recognition from
the original UL file.
Dead Band
The time period in a control system
between a change in stimuli and any
measurable response in the controlled
variable. In the deadband, specific
conditions can be placed on control
output actions. Operators select the dead
band width. It is usually above the
heating proportional band and below the
cooling proportional band.
Derivative
The rate of change in a process variable
which forms the “D” in a PID control
algorithm. This control action anticipates
the rate of change of the process and
compensates to minimize overshoot and
undershoot. Derivative control is an
instantaneous change of the control
output in the same direction as the
proportional error. This is caused by a
change in the process variable (PV) that
decreases over the derivative time.
Deviation
A departure of a controlled variable from
a command such as set point.
Deviation indication
A system of indication in which a
departure of a detected value from the
set point is indicated.
DIN (Deutsche Industrial Norm)
A German standards agency that sets
world-recognized engineering and
industrial standards.
DIN 43760
The standard that defines the
characteristics of a 100-ohm platinum
RTD having a resistance vs. temperature
curve specified by a = 0.00385 ohms per
degree.
Drift
A gradual change over a long period of
time that affects the reading or value.
Changes in ambient temperature,
component aging, contamination,
humidity and line voltage all contribute to
drift.
Droop
Controllers using only proportional
control can settle at a value below the
actual set point once the system
stabilizes. This offset is corrected with
the addition of Integral control in the
control algorithm.
Electromagnetic Compatibility
To conform with CE’s EMC requirements,
equipment or a system must operate
without introducing significant
electromagnetic disturbances to the
environment or be affected by
electromagnetic disturbances.
Electromagnetic Interference
There are many possible sources for
electromagnetic interference (EMI) in an
industrial control setting. It can originate
as electrical or magnetic noise caused by
switching AC power on inside the sine
E--21
REFERENCE
INFORMATION
wave. EMI interferes with the operation
of controls and other devices. The EMC
section in Specifications shows a
controller’s resistance to EMI.
Electromechanical Relay
A power switching device that completes
or interrupts a circuit by physically
moving electrical contacts into contact
with each other. These are used primarily
for ON/OFF control operation.
Event
A programmable ON/OFF output signal.
Events can control peripheral equipment
or processes, or act as an input for
another control loop. Event input boards
are an option for most Omron controllers.
Infrared
Manual Mode
The portion of the electromagnetic
spectrum with wavelengths ranging from
one to 1000 microns. These wavelengths
are ideal for radiant heating and
non-contact temperature sensing.
A selectable mode that has no automatic
control aspects. The user sets the output
levels.
Input Digital Filter
A device used to sample the input slower
than the scan rate to allow the controller
to monitor an input that changes very
rapidly and still have sufficient
information from the process to control it.
Input Scaling
The ability to scale input readings (% of
full scale) to the engineering units of the
process variable.
Fahrenheit
Input Type
A temperature scale that has 32° at the
ice point and 212° at the boiling point of
water at sea level. To convert Fahrenheit
to Celsius, subtract 32 from °F and
multiply the remainder by 0.556.
The type of device used to provide a
signal of temperature change. These
include thermocouples, RTDs, linear or
process current or voltage inputs.
Full Indication
A system of indication in which a
detected value is indicated with a setting
range.
Control action that eliminates offset, or
droop, between set point and actual
process temperature. This is the “I” in the
PID control algorithm.
Fuzzy Logic
Joint Industrial Standards (JIS)
A rule-based control algorithm that
enables control devices to make
subjective judgments in a way similar to
human decision-making. Within a
process controller, fuzzy logic uses some
basic information about the system,
which is input by the user, to emulate the
way an expert operator who was
manually controlling the system would
react to a process upset.
A Japanese agency that establishes and
maintains standards for equipment and
components. It’s function is similar to
Germany’s Deutsche Industrial Norm.
Heat Sink
This alarm indicates a problem in the
control loop, e.g., a sensor has become
disconnected or a problem has
developed with the final control element.
An object that conducts and dissipates
heat away from an object in contact with
it. Solid state relays usually use a finned
aluminum heat sink to dissipate heat.
Hot Junction and Cold Junction
If a thermocouple is generating a voltage,
this means that there is a temperature
difference between the two ends of the
thermocouple. The hot end is the one
that makes contact with the temperature
process being controlled. The cold end is
at the sensor input terminals.
Integral Action (I)
Linearity
A measure of the deviation of an
instrument’s response from a straight
line.
Loop Break Alarm
Manipulated Variable
The final output percentage (0 to 100%)
that will be sent to a control element.
This percentage can be related to a
valve position, a 4-20 mA signal, or the
amount of ON time from a pulsed control
output.
Manipulated Variable Forcing
Oscillation of the process temperature
between the set point and the process
variable. Derivative control is used in the
control algorithm to reduce hunting.
The manipulated variable can be forced
to a specified user-programmed value
under the following circumstances:
1. A sensor break occurs
2. An error in the process occurs
3. Stop mode is activated
Hysteresis (Dead Band)
Manipulated Variable Limiting
A temperature band between the ON and
OFF of an output in the ON/OFF control
action. No heating or cooling takes place.
The band occurs between the ON and
OFF points.
A control option used when the process
cannot handle the full output of the
heater or final control device. To limit the
manipulated variable, the user programs
the controller so that it never sends a
100% output to the final control element.
Hunting
E--22
Multiple Set Points
Two or more set points independent from
each other which can be set in the
temperature controller.
National Electrical Manufacturers
Association (NEMA)
The United States organization that
establishes specifications and ratings for
electrical components and apparatus.
Conformance by manufacturers is
voluntary. However, Underwriters
Laboratories will test products to NEMA
ratings for operating performance and
enclosure ratings.
National Institute of Standards
and Technology (NIST)
Formerly the National Bureau of
Standards, this United States agency is
responsible for establishing scientific and
technical standards.
NEMA 4X
This enclosure rating specification
certifies that a controller’s front panel
resists water washdown and is corrosion
resistant in indoor usage.
Normal Action
A control action which will increase the
control output if the process value is
higher than the set point. This action is
suitable for a cooling system.
Offset
A controlled deviation (the difference in
temperature between the set point and
the actual process temperature)
remaining after a controlled system
reaches its steady state. The offset
(droop) is created by the correlation
between the thermal capacity of the
controlled system and the capacity of
heating equipment.
ON/OFF Control Action
A control action which turns the output
fully on until the set point is reached, and
then turns off. Also called “two-position”
control action.
Overshoot
The number of degrees by which a
process exceeds the set point
temperature.
Process Variable
The parameter that is controlled or
measured, such as temperature, relative
humidity, flow and pressure.
Proportional Band
The range of temperature in which a
manipulated variable is proportionate to
any deviation from the set point.
REFERENCE
INFORMATION
Proportional Control Action (P)
Reverse Action
Underwriters Laboratories (UL)
A control action in which the manipulated
variable is proportionate to any deviation
from the set point.
A control action in which the output
power will be inversely proportional to
the deviation. An increase in the process
variable will cause a decrease in the
output power, making this action suitable
for a heating system.
This independent testing laboratories
establishes commercial and industrial
standards, as well as tests and certifies
products in the US. They also offer
testing to Canadian Standards
Association requirements with products
bearing the “cUL” marking.
Proportional Period
A cycle of ON and OFF operations of the
output relay in a time-division
proportional control action.
Proportioning Control Plus
Derivative Function (PD)
A time-proportioning controller that has a
derivative function. The derivative
function monitors the rate at which a
system’s temperature is either increasing
or decreasing and adjusts the cycle time
of the controller to minimize overshoot or
undershoot.
Proportioning Control with
Integral and Derivative Functions
(PID)
A time-proportioning controller that has
integral and derivative functions. The
integral function automatically raises the
stabilized system temperature to match
the set point temperature to eliminate the
difference caused by the
time-proportioning function. The
derivative function monitors the rate of
rise or fall of the system temperature and
automatically adjusts the cycle time of
the controller to minimize overshoot and
undershoot. Also called “three-mode”
control.
Range
The difference between the lower and
upper limits of a measurement quantity.
Rate Action (D)
The controller senses the rate of change
of temperature and provides an
immediate change of output to minimize
the eventual deviation.
Remote Set Point
A remote set point allows a controller to
receive its set point from a source other
than itself.
Reset (Auto Reset) Action
There is a manual adjustment that can
be applied to the offset by changing the
set value dial or moving the offset screw
on the control panel. The auto-reset
function automatically adjusts the set
value to eliminate offset.
Resistance Temperature Detector
(RTD)
A coil of wire, usually platinum, whose
resistance increases linearly with a rise
in temperature. RTD’s generally have a
higher accuracy rating than
thermocouples.
Serial Communications
A method of transmitting information
between devices by sending all bits
serially over a communication channel.
RS-232 is used for point-to-point
connections of a single device, usually
over a short distance.
RS-422/RS-485 communicates with
multiple devices on a single, common
cable over longer distances.
Set Point
The value set on the process or
temperature controller to control the
system.
Undershoot
This is the amount by which the process
variable falls below the set point before it
stabilizes.
Zero Cross Switching
Used in solid state relays, this action
provides output switching only at or near
the zero-voltage crossing point of the AC
sine wave. It reduces electromagnetic
interference and high inrush currents
during initial turn-on.
Soft Start
A method of applying power gradually
over a period of seconds to controlled
devices such as heaters, pumps and
motors. This lengthens the service life of
the load by limiting in-rush current to
inductive loads.
Solid State Relay (SSR)
A switching device with no moving parts
that completes or interrupts a circuit
electrically.
Thermal Response
The time required for the response curve
of the temperature sensor to rise to a
specified percentage level (usually either
63% or 90%).
Thermistor Sensor
A small bead of semiconducting material
at the tip detects temperature. The
resistance of the bead decreases
significantly with a rise in temperature for
a highly sensitive input device.
Thermocouple Sensor
A device the converts heat to electricity.
Usually made of two wires, each of a
different metal or alloy. The wires are
joined at one end, known as the “hot
end”. The hot end makes thermal contact
with the process to be controlled. The
cold end terminals are connected to the
sensor input. Voltages are created at
both the hot and cold ends. The
controller measures the cold end
temperature to determine the hot end
temperature.
E--23
REFERENCE
INFORMATION
Enclosure Ratings
J NEMA RATINGS AT A GLANCE FOR NON-HAZARDOUS LOCATIONS
Type of enclosure
Protection against
g
these
environmental
i
t l conditions
diti
1
2
3
3R
3S
4
4X
5
6
6P
11
12
12K
13
Accidental contact with the enclosed
equipment
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Falling dirt
X
X
----
----
----
X
X
X
X
X
X
X
X
X
Falling liquids, light splashing
----
X
----
----
----
X
X
----
X
X
X
X
X
X
Dust, lint, fibers and flyings
(non-combustible, non-ignitable)
----
----
----
----
----
X
X
X
X
X
----
X
X
X
Windblown dust
----
----
X
----
X
X
X
----
X
X
----
----
----
----
Hosedown and splashing water
----
----
----
----
----
X
X
----
X
X
----
----
----
----
Oil and coolant seepage
----
----
----
----
----
----
----
----
----
----
----
X
X
X
Oil or coolant spraying and splashing
----
----
----
----
----
----
----
----
----
----
----
----
----
X
Corrosive agents
----
----
----
----
----
----
X
----
----
X
X
----
----
----
Occasional temporary submersion
----
----
----
----
----
----
----
----
X
X
----
----
----
----
Occasional prolonged submersion
----
----
----
----
----
----
----
----
----
X
----
----
----
----
J IEC (INTERNATIONAL ELECTROTECHNICAL COMMISSION) RATINGS
The IEC defines degrees of protection
provided by electrical enclosures with
respect to personnel, equipment within
the enclosure and ingress of water. The
degree of protection is expressed by the
letters “IP” followed by two numerals
(Example: IP67). See the table at right
for an explanation of the numerals. The
following information is drawn from IEC
publication 144 of 1963 and 529 of 1976.
By contrast to NEMA, “IP” ratings do not
apply to protection against the risk of
explosion or conditions such as humidity,
corrosive gases, fungi or vermin. Also,
different parts of a piece of equipment
can have different degrees of protection
and still comply with the standards. An
example would be the opening in the
base of an enclosure.
1st characteristic numeral
2nd characteristic numeral
Protection against contact and penetration of solid bodies
Protection against the penetration of lqiuids.
0
Not protected
0
Not protected.
1
Protection against solid objects greater than 50 mm.
1
Protection against dripping water.
2
Protection against solid objects greater than 12 mm.
2
Protection against dripping water when tilted up to 15°.
3
Protection against solid objects greater than 2.5 mm.
3
Protection against rain.
4
Protection against solid objects greater than 1 mm.
4
Protection against splashing water.
5
Dust protected.
5
Protection against water jets.
6
Dust tight.
6
Protection against heavy seas.
----
----
7
Protection against the effects of immersion
----
----
8
Protection against immersion.
E--24
REFERENCE
INFORMATION
J THERMOELECTRIC VOLTAGE FOR THERMOCOUPLE SENSORS (in mV)
Type K Thermocouples
Meet NBS 561, DIN 43710 1977, BS 4937 1973, JIS-C 1602-1981
Temperature °C
0
10
20
30
40
50
60
70
80
90
0
0.000
0.397
0.798
1.203
1.611
2.022
2.436
2.850
3.266
3.681
100
4.095
4.508
4.919
5.327
5.733
6.137
6.539
6.939
7.338
7.737
200
8.137
8.537
8.938
9.341
9.745
10.151
10.560
10.969
11.381
11.793
300
12.207
12.623
13.039
13.456
13.874
14.292
14.712
15.132
15.552
15.974
400
16.395
16.818
17.241
17.664
18.088
18.513
18.938
19.363
19.788
20.214
500
20.640
21.066
21.493
21.919
22.346
22.772
23.198
23.624
24.050
24.476
600
24.902
25.327
25.751
26.176
26.599
27.022
27.445
27.867
28.288
28.709
700
29.128
29.547
29.965
30.383
30.799
31.214
31.629
32.042
32.455
32.866
800
33.277
33.686
34.095
34.502
34.909
35.314
35.718
36.121
36.524
36.925
900
37.325
37.724
38.122
38.519
38.915
39.310
39.703
40.096
40.488
40.879
1000
41.269
41.657
42.045
42.432
42.817
43.202
43.585
43.968
44.349
44.729
1100
45.108
45.486
45.863
46.238
46.612
46.985
47.356
47.726
48.095
48.462
1200
48.828
49.192
49.555
49.916
50.276
50.633
50.990
51.344
51.697
52.049
1300
52.398
52.747
53.093
53.439
53.782
54.125
54.466
54.807
—
—
Type J Thermocouples
Meet NBS 561, BS 4937 1973, JIS-C 1602-1981
Temperature °C
0
0
10
20
30
40
50
60
70
80
90
0.000
0.507
1.019
1.536
2.058
2.585
3.115
3.649
4.186
4.725
100
5.268
5.812
6.359
6.907
7.457
8.008
8.560
9.113
9.667
10.222
200
10.777
11.332
11.887
12.442
12.998
13.553
14.108
14.663
15.217
15.771
300
16.325
16.879
17.432
17.984
18.537
19.089
19.640
20.192
20.743
21.295
400
21.846
22.397
22.949
23.501
24.054
24.607
25.161
25.716
26.272
26.829
500
27.388
27.949
28.511
29.075
29.642
30.210
30.782
31.356
31.933
32.513
600
33.096
33.683
34.273
34.867
35.464
36.066
36.671
37.280
37.893
38.510
700
39.130
39.754
40.382
41.013
41.647
42.283
42.922
43.563
44.207
44.852
800
45.498
46.144
46.790
47.434
48.096
48.716
49.354
49.989
50.621
51.249
900
51.875
52.496
53.115
53.729
54.341
54.948
55.553
56.155
56.753
57.349
1000
57.942
58.533
59.121
59.708
60.293
60.876
61.459
62.039
62.619
63.199
1100
63.777
64.355
64.933
65.510
66.087
66.664
67.240
67.815
68.390
68.964
1200
69.536
—
—
—
—
—
—
—
—
—
Type J-DIN Thermocouples (Fe-CuNi)
Meet DIN 43710 1977
Temperature °C
Note:
0
10
20
30
40
50
60
70
80
90
0
0.000
0.520
1.050
1.580
2.110
2.650
3.190
3.730
4.270
4.820
100
5.370
5.920
6.470
7.030
7.590
8.150
8.710
9.270
9.830
10.222
200
10.950
11.510
12.070
12.630
13.190
13.750
14.310
14.880
15.440
16.000
300
16.560
17.120
17.680
18.240
18.800
19.360
19.920
20.480
21.040
21.600
400
22.160
22.720
23.290
23.860
24.430
25.000
25.570
26.140
26.710
27.280
500
27.850
28.430
29.020
29.590
30.170
30.750
31.330
31.910
32.490
33.080
600
33.670
34.260
34.850
35.440
36.040
36.640
37.250
37.850
38.470
39.090
700
39.720
40.350
40.980
41.620
42.270
42.920
43.570
44.230
44.890
45.550
800
46.220
46.890
47.570
48.250
48.940
49.630
50.320
51.020
51.720
52.431
The reference junction for thermocouples is at 0°C.
E--25
REFERENCE
INFORMATION
Type R Thermocouples
Meet NBS 561, BS 4937 1973, JIS-C 1602-1981
Temperature °C
0
10
20
30
40
50
60
70
80
90
0
0.000
0.054
0.111
0.171
0.232
0.296
0.363
0.431
0.501
0.573
100
0.647
0.723
0.800
0.879
0.959
1.041
1.124
1.208
1.294
1.380
200
1.468
1.557
1.647
1.738
1.830
1.923
2.017
2.111
2.207
2.302
300
2.400
2.498
2.596
2.695
2.795
2.896
2.997
3.099
3.201
3.304
400
3.407
3.511
3.616
3.721
3.826
3.933
4.039
4.146
4.254
4.362
500
4.471
4.580
4.689
4.799
4.910
5.021
5.132
5.244
5.356
5.469
600
5.582
5.696
5.810
5.925
6.040
6.155
6.272
6.388
6.505
6.623
700
6.741
6.860
6.979
7.098
7.218
7.339
7.460
7.582
7.703
7.826
800
7.947
8.072
8.196
8.320
8.445
8.570
8.696
8.822
8.949
9.076
900
9.203
9.331
9.460
9.589
9.718
9.848
9.978
10.109
10.240
10.371
1000
10.503
10.636
10.768
10.902
11.035
11.170
11.304
11.439
11.574
11.710
1100
11.846
11.983
12.119
12.257
12.394
12.532
12.669
12.808
12.946
13.085
1200
13.224
13.363
13.502
13.642
13.782
13.922
14.062
14.202
14.343
14.483
1300
14.624
14.765
14.906
15.047
15.188
15.329
15.470
15.611
15.752
15.893
1400
16.035
16.176
16.317
16.458
16.599
16.741
16.882
17.022
17.163
17.304
1500
17.445
17.585
17.726
17.866
18.006
18.146
18.286
18.425
18.564
18.703
1600
18.842
18.981
19.119
19.257
19.395
19.533
19.670
19.807
19.941
20.080
1700
20.215
20.350
20.483
20.616
20.748
20.878
21.006
—
—
—
Type S Thermocouples
Meet NBS 561, DIN 43710 1977, BS 4937 1973, JIS-C 1602-1981
Temperature °C
Note:
E--26
0
10
20
30
40
50
60
70
80
90
0
0.000
0.055
0.113
0.173
0.235
0.299
0.365
0.432
0.502
0.573
100
0.645
0.719
0.795
0.872
0.950
1.029
1.109
1.190
1.273
1.356
200
1.440
1.525
1.611
1.698
1.785
1.873
1.962
2.051
2.141
2.232
300
2.323
2.414
2.506
2.599
2.692
2.786
2.880
2.974
3.069
3.164
400
3.260
3.356
3.452
3.549
3.645
3.743
3.840
3.938
4.036
4.135
500
4.234
4.333
4.432
4.532
4.632
4.732
4.832
4.933
600
5.237
5.339
5.442
5.544
5.648
5.751
5.855
5.960
6.064
6.169
700
6.274
6.380
6.486
6.592
6.699
6.805
6.913
7.020
7.128
7.236
800
7.345
7.454
7.563
7.672
7.782
7.892
8.003
8.114
8.225
8.336
900
8.448
8.560
8.673
8.786
8.899
9.012
9.126
9.240
9.355
9.470
1000
9.585
9.700
9.816
9.932
10.048
10.165
10.282
10.400
10.517
10.635
50.34
5.136
1100
10.754
10.872
10.991
11.110
11.229
11.348
11.467
11.587
11.707
11.827
1200
11.947
12.067
12.188
12.308
12.429
12.550
12.671
12.792
12.913
13.034
1300
13.155
13.276
13.397
13.519
13.640
13.716
13.883
14.004
14.125
14.247
1400
14.368
14.489
14.610
14.731
14.852
14.973
15.094
15.215
15.336
15.456
1500
15.576
15.697
15.817
15.937
16.057
16.176
16.296
16.415
16.534
16.653
1600
16.771
16.890
17.008
17.125
17.243
17.360
17.477
17.594
17.711
17.826
1700
17.942
18.056
18.170
18.282
18.394
18.504
18.612
—
—
—
The reference junction for thermocouples is at 0°C.
REFERENCE
INFORMATION
J TEMPERATURE vs. RESISTANCE FOR PLATINUM RTD SENSORS (Ohms)
Sensors Conform to JIS-C 1604 1981 Standard
Temperature °C
--200
0
10
20
30
40
50
60
70
17.14
21.46
25.80
30.12
34.42
38.68
42.91
47.11
80
90
51.29
55.44
--100
59.57
63.68
67.77
71.85
75.91
79.96
83.99
88.01
92.02
96.02
0
100.00
103.97
107.93
111.88
115.81
119.73
123.64
127.54
131.42
135.30
100
139.16
143.01
146.85
150.67
154.49
158.29
162.08
165.86
169.63
173.38
200
177.13
180.86
184.58
188.29
191.99
195.67
199.35
203.01
206.66
210.30
300
213.93
217.54
221.15
224.74
228.32
231.89
235.45
238.99
242.53
246.05
400
249.56
253.06
256.55
260.02
263.49
266.94
270.38
273.80
277.22
280.63
500
284.02
287.40
290.77
294.12
297.47
300.80
304.12
307.43
310.72
600
317.28
320.54
323.78
327.02
330.24
—
—
—
—
314.01
—
Sensors Conform to DIN 43760 1968, BS1964 1904 Standard
Temperature °C
0
10
20
30
40
50
60
70
--200
18.53
22.78
27.05
31.28
35.48
39.65
43.80
--100
60.20
64.25
68.28
72.29
76.28
80.25
84.21
0
100.00
103.90
107.79
111.67
115.54
119.40
100
138.50
142.28
146.06
149.82
153.57
200
175.84
179.51
183.17
186.82
190.46
300
212.03
215.58
219.13
222.66
400
247.06
250.50
253.93
257.34
500
280.93
284.26
287.57
600
313.65
316.86
320.05
700
345.21
—
—
80
90
47.93
52.04
56.13
88.17
92.13
96.07
123.24
127.07
130.89
134.70
157.32
161.04
164.76
168.47
172.16
194.08
197.70
201.30
204.88
208.46
226.18
229.69
233.19
236.67
240.15
243.61
260.75
264.14
267.52
270.89
274.25
277.60
290.87
294.16
297.43
300.70
303.95
307.20
310.43
323.24
326.41
329.57
332.72
335.86
338.99
—
—
—
—
—
—
342.10
—
E--27
REFERENCE
INFORMATION
J RESISTANCE RATIO THERMISTOR SENSORS
Temperature Characteristics
Operating
p
g
t
temperature
t
°C
E--28
Ratio
deviation
--55
3.514
—
--50
3.415
--40
3.168
--30
Operating
p
g
t
temperature
t
°C
0° to 100°C
Ratio
Ratio
deviation
Operating
p
g
t
temperature
t
°C
50° to 150°C
Ratio
Ratio
deviation
--10
3.689
—
40
3.774
—
±0.022
0
3.415
±0.030
50
3.415
±0.037
±0.029
10
3.096
±0.033
60
3.051
±0.036
2.851
±0.034
20
2.755
±0.034
70
2.700
±0.034
--20
2.497
±0.036
30
2.419
±0.033
80
2.377
±0.031
--10
2.148
±0.033
40
2.110
±0.029
90
2.089
±0.027
0
1.841
±0.028
50
1.841
±0.025
100
1.841
±0.023
10
1.592
±0.022
60
1.617
±0.020
110
1.630
±0.019
20
1.403
±0.017
70
1.436
±0.016
120
1.454
±0.016
30
1.264
±0.012
80
1.293
±0.013
130
1.309
±0.013
40
1.165
±0.009
90
1.181
±0.010
140
1.191
±0.011
50
1.094
±0.006
100
1.094
±0.008
150
1.094
±0.009
110
1.026
—
160
1.015
—
Operating
p
g
t
temperature
t
°C
Note:
--50° to 50°C
Ratio
100° to 250°C
Ratio
Ratio
deviation
Operating
p
g
t
temperature
t
°C
150° to 300°C
Ratio
Ratio
deviation
Operating
p
g
t
temperature
t
°C
200° to 350°C
Ratio
Ratio
deviation
90
3.627
—
140
3.672
—
190
3.665
—
100
3.415
±0.022
150
3.415
±0.026
200
3.415
±0.025
110
3.186
±0.023
160
3.161
±0.025
210
3.167
±0.025
120
2.953
±0.023
170
2.916
±0.024
220
2.926
±0.024
130
2.722
±0.023
180
2.683
±0.023
230
2.695
±0.023
140
2.499
±0.022
190
2.466
±0.021
240
2.477
±0.021
150
2.290
±0.020
200
2.265
±0.019
250
2.274
±0.020
160
2.096
±0.019
210
2.083
±0.018
260
2.088
±0.018
170
1.921
±0.017
220
1.917
±0.016
270
1.919
±0.016
180
1.764
±0.015
230
1.768
±0.014
280
1.767
±0.014
190
1.626
±0.013
240
1.634
±0.013
290
1.633
±0.013
200
1.504
±0.012
250
1.515
±0.011
300
1.517
±0.011
210
1.398
±0.010
260
1.409
±0.010
310
1.411
±0.010
220
1.305
±0.009
270
1.316
±0.009
320
1.317
±0.009
230
1.225
±0.008
280
1.232
±0.008
330
1.223
±0.008
240
1.155
±0.007
290
1.159
±0.007
340
1.160
±0.007
250
1.094
±0.006
300
1.094
±0.006
350
1.094
±0.006
260
1.041
—
310
1.036
—
360
1.036
—
“Ratio deviation” means a deviation in the ratio of resistance from specified temperature per each 1°C change in the measured
temperature.
REFERENCE
INFORMATION
J INTERCHANGEABLE THERMISTOR SENSORS
Resistance vs. Temperature Characteristics
These values apply to thermistor sensors used with E5C2 temperature controllers.
Range
--50° to 100°C
Range
0° to 150°C
Range
50° to 200°C
Resistance
6 KΩ at 0°C (nominal)
Resistance
30 KΩ at 0°C (nominal)
Resistance
3 KΩ at 100°C (nominal)
Constant B
3390K
Constant B
3450K
Constant B
3894K
Temperature °C
Resistance
(KΩ)
Temperature °C
Resistance
(KΩ)
Deviation
(KΩ)
Temperature °C
Resistance
(KΩ)
Deviation
(KΩ)
Deviation
(KΩ)
--50
75.360
±4.280
--20
77.070
—
30
28.050
--40
42.900
±2.280
--10
47.410
—
40
19.310
—
—
--30
25.230
±1.260
0
30.000
±1.350
50
13.570
±0.470
--20
15.210
±0.720
10
19.490
±0.800
60
9.717
±0.310
--10
9.414
±0.422
20
12.970
±0.500
70
7.081
±0.214
0
6.000
±0.261
30
8.828
±0.323
80
5.243
±0.151
10
3.934
±0.158
40
6.140
±0.212
90
3.939
±0.108
20
2.637
±0.100
50
4.356
±0.144
100
3.000
±0.080
30
1.812
±0.065
60
3.147
±0.098
110
2.314
±0.058
40
1.266
±0.043
70
2.317
±0.068
120
1.805
±0.043
50
0.904
±0.029
80
1.734
±0.048
130
1.424
±0.033
60
0.685
±0.020
90
1.318
±0.035
140
1.134
±0.025
70
0.487
±0.014
100
1.017
±0.026
150
0.912
±0.019
80
0.366
±0.010
110
0.794
±0.019
160
0.735
±0.015
90
0.279
±0.007
120
0.628
±0.014
170
0.596
±0.012
100
0.216
±0.005
130
0.502
±0.011
180
0.487
±0.010
110
0.168
—
140
0.405
±0.008
190
0.400
±0.008
120
0.133
—
150
0.330
±0.006
200
0.331
±0.006
160
0.272
—
170
0.226
—
Range
100° to 250°C
Range
150° to 300°C
Range
200° to 350°C
Resistance
550 Ω, 200°C (nominal)
Resistance
4 KΩ at 200°C (nominal)
Resistance
8 KΩ at 200°C (nominal)
Constant B
4300K
Constant B
5133K
Constant B
5559K
Temperature °C
Resistance
(KΩ)
Temperature °C
Resistance
(KΩ)
Temperature °C
Resistance
(KΩ)
Deviation
(KΩ)
Deviation
(KΩ)
Deviation
(KΩ)
80
12.660
—
130
23.060
—
180
13.390
90
8.626
—
140
17.440
—
190
10.290
—
—
100
6.281
±0.194
150
13.330
±0.350
200
38.000
±0.190
110
4.649
±0.134
160
10.290
±0.260
210
6.305
±0.146
120
3.495
±0.096
170
8.027
±0.194
220
5.015
±0.111
130
2.664
±0.069
180
6.312
±0.147
230
4.014
±0.086
140
2.056
±0.051
190
5.006
±0.113
240
3.240
±0.067
150
1.510
±0.039
200
4.000
±0.087
250
2.634
±0.054
160
1.273
±0.029
210
3.221
±0.068
260
2.156
±0.042
170
1.017
±0.022
220
2.611
±0.053
270
1.779
±0.033
180
0.824
±0.017
230
2.131
±0.042
280
1.474
±0.027
190
0.669
±0.013
240
1.751
±0.034
290
1.228
±0.022
200
0.550
±0.010
250
1.445
±0.027
300
1.030
±0.018
210
0.455
±0.008
260
1.202
±0.022
310
0.868
±0.014
220
0.381
±0.007
270
1.004
±0.018
320
0.738
±0.012
230
0.319
±0.005
280
0.842
±0.014
330
0.631
±0.010
240
0.270
±0.004
290
0.711
±0.012
340
0.542
±0.008
250
0.230
±0.003
300
0.602
±0.010
350
0.468
±0.007
260
0.197
—
310
0.513
—
270
0.169
—
320
0.428
—
Note:
“Resistance deviation” means a deviation of actual resistance at the specified temperature per each 1°C change in the measured
temperature.
E--29
REFERENCE
E--30
INFORMATION
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