DX5100 TableTop Quick Start

RMT Ltd.
Thermoelectric Module Controller
DX5100 – Table Top
Quick Start
User Guide
RMT Ltd.
Moscow 2014
Version 1.01
Controller DX5100 Table Top. Quick Start
RMT Ltd.
Table of Contents
Features and benefits ......................................................................................................................... 3
Specifications ..................................................................................................................................... 3
Common ......................................................................................................................................... 3
Performance ................................................................................................................................... 3
Dimensions ..................................................................................................................................... 5
Thermal mounting considerations ...................................................................................................... 7
How to Get Connected ....................................................................................................................... 7
RS485 Connection .......................................................................................................................... 7
TEC Connection .............................................................................................................................. 7
Thermistor and TEC Connection .................................................................................................... 7
Power Connection........................................................................................................................... 8
Getting Started ................................................................................................................................... 9
Operation Modes ................................................................................................................................ 9
DX5100 Vision .................................................................................................................................. 10
Thermistor Settings .......................................................................................................................... 11
Procedure Description .................................................................................................................. 11
Thermistor Current Settings .......................................................................................................... 11
Choice of Thermistor Type ........................................................................................................... 13
Temperature as Function of Resistance: ...................................................................................... 13
Calibration of Temperature Measurement Channel ..................................................................... 14
Setting Alarm Limits.......................................................................................................................... 16
Setting Limits of TEC Voltage ....................................................................................................... 16
Setting Temperature Limit Values ................................................................................................ 16
PID Tuning ........................................................................................................................................ 18
PID Tuning Tips ............................................................................................................................ 18
Routine Operation ............................................................................................................................ 20
Autostart ........................................................................................................................................ 20
Mode "Program" ............................................................................................................................ 21
T-Regulation (Relay) ..................................................................................................................... 21
Constant Voltage .......................................................................................................................... 22
PID regulation (Constant Temperature)........................................................................................ 22
Monitoring ......................................................................................................................................... 23
TEC Control: DC versus PWM ......................................................................................................... 24
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Controller DX5100 - Table Top. Quick Start
Features and benefits
-
Bi-directional temperature regulation (heating and cooling) of a TEC with high accuracy
-
Work with RTD sensor and thermistors of both NTC and PTC types (known T=f(R) resistance
range 70 Ohm…996 kOhm)
-
One or two TECs controlled
-
TEC operation current and voltage range as ±4A and ±8V per channel.
-
PID temperature regulation mode
-
Constant voltage operation mode (4 wire possibility)
-
T-Regulation (relay) mode
-
Mode of temperature programming in time
-
DC regulation of TEC in all operation modes
-
Diagnostics of TEC performance by the Z-metering approach
-
PID auto-tuning function
-
Independent work without remote computer, based on preset and programmed start.
-
Communication interfaces USB and RS485
-
Network of up to 32 Channels is available jointed by RS485 bus
-
Software for controlling
-
Protocol WAKE for user software programming
Specifications
Common
Name
Units
Value
Comments
Yes
Yes
Yes
Yes
TEC bi-directional
(heating and cooling)
Operation Modes
PID
Constant voltage
Temperature Program
Т-regulation (relay)
Possibility of Operation Modes Of
Regulation after Restarting
Local control
Remote control
Yes
Yes
Yes
USB
RS485
WAKE
32 (128)
Communication interfaces
Communication protocol
Maximal number of channels in network
Programmable thresholds
Temperatures
Max voltage
Operational temperatures range
Storage temperatures range
Humidity
Power supply
°C
°C
%
V
2
1
0…+45
-20…+60
5…95%
12
2 buttons
BIN & SYM
Combined by RS485
Each Channel
Performance
Name
Maximum current
Maximum voltage
Maximum power
Version 1.01 2014
Units
Value
Absolute Maximum Parameters
A
4
8
V
32
W
Comments
Per channel
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Controller DX5100 Table Top. Quick Start
Name
RMT Ltd.
Units
Value
2
Regulation channels number
Parameters of TEC Voltage Regulation
Voltage Range
V
-8…+8
Accuracy of voltage regulation
mV
1
Resolution of voltage setting
mV
0.13
Resolution of measurement
6
V
Output ripple, not more
10
V
Efficiency of converters
%
85
Temperature Regulation
4-wire sensing
Yes
Resolution
°C
0.001
Stability
°C
0.005
Accuracy
°C
0.5
Types of Thermosensors
Platinum thermistor
Pt
Other types of thermistors
NTC, PTC
Resistance range
Ohm
70…996K
Mode «Program»
Programs number, max
16
Program steps number, max
50
Steps number in a process
800
Program step duration, max
s
65 535
Time interval accuracy
s
1
Different operational modes when
Yes
temperature programming in time
Programs cascading
Yes
Comments
Typical values.
Depend on
thermistors type
Known T=f(R)
0..15
0..49
Programs in series
The given data are true for the ambient temperature 23±5°C and humidity 45±15%
Important! The DX5100 Table Top controller is based on DC current regulation by TEC
in all operational modes (See chapter “TEC Control: DC versus PWM”).
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Controller DX5100 - Table Top. Quick Start
Dimensions
3
2
1
8
4
9
6
3
2
10
5
7
1
2
3
4
5
6
7
8
9
10
11
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11
Housing
Left panel
Right panel
TEC2 Connecting
TEC1 Connecting
Indicator (LCD Display)
Control buttons
Power switch
Power connector
Connector miniUSB
RS485 Connector
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Controller DX5100 Table Top. Quick Start
RMT Ltd.
PHOENIX CONTACT Connectors
MC 1,5/ 2-ST-3,81
MC 1,5/ 3-ST-3,81
1803578 - 1pcs
1803581 – 1pcs
MC 1,5/10-ST-3,81
1803659 - 2pcs
PHOENIX CONTACT cable housing
KGG-MC 1,5/ 2
1834343 –
1pcs
KGG-MC 1,5/ 3
1834356
1pcs
KGG-MC 1,5/10
1834424
2pcs
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Controller DX5100 - Table Top. Quick Start
Thermal mounting considerations
The DX5100 TABLE TOP controllers may generate a significant amount of heat TEC pumping
power. They must be adequately heat sinked in order to prevent overheating of the controller. An
external heat sinking may be necessary depending on TEC pumping power and ambient
temperature.
Important! Ensure adequate heat dissipation from DX5100 in order to prevent its
overheating.
How to Get Connected
There are connection terminals on both sides of the controller.
RS485 Connection
Signal A of interface RS485
Signal B of interface RS485
Signal GND of interface RS485
TEC Connection
Important! Ensure proper heat dissipation from hot side of your TEC by using proper
heat sink and good thermal contact between TEC hot side and a heat sink
Important! Any TEC must be connected according to its polarity to operate in cooling
mode.
Thermistor and TEC Connection
DX5100 Table Top controllers have two channels for TEC control. You can run one channel only or
both channels simultaneously.
Important! Thermistor position must be carefully selected according to the design
of an object (heat load) on a cold side of TEC, ensuring minimum possible temperature
gradient between the thermistor and TEC cold side. Perfect thermal contact between the
thermistor and an object (heat load) is required.
The thermistor may be connected by a 4-wire or 2-wire circuit as shown on the figure below.
We recommend always connect the thermistor by two twisted pairs for 4-wire circuit. 2-wire
connection may be used for thermistor resistance exceeding 1000 Ohm. For this connection,
correspondent connecting terminals contacts should be bridged.
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RMT Ltd.
to FAN
if need
TEC
to FAN
if need
TEC
Thermistor
Recommended connections of TEC and thermistor
Thermistor
Connections possible for thermistor resistance
exceeding 1000 Ohm
Connections of TEC and thermistor to the controller
Power Connection
Connect the power supply having the polarity in mind. The power supply source should provide
voltage 12±10% V.
Power +
Power Important! Power supply must be chosen based on the number and the total power
consumption of the controller power boards. If the maximum power available for the
control of a TEC (Imax and Umax) is less than the maximum value of the power board
(boards) of the controller, the power supply block can have a lower power
correspondingly.
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Controller DX5100 - Table Top. Quick Start
Getting Started
You will need a PC to get DX5100 controller up and running when you switch it for the first time.
After that, you may not need it in everyday use.
Operation Modes
There are several modes of regulation available by DX5100:





Regulation is off (idle)
Mode "Program"
T-regulation (relay)
PID regulation
Constant voltage maintenance
Important! Before selection of operation mode, important setting and calibration
procedures must be obtained. The procedures are described below. Missing these
procedures may result in permanent failures and fatal damages to controllers, TECs
and objects controlled.
All controllers are set to “Idle” mode before shipment. The controller must be in “Idle”
mode if you set or re-set any parameter in order to exclude permanent failures and
fatal damages to controllers, TECs and objects controlled during the procedure. Check
operation mode carefully before starting any setting or re-setting procedure.
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Controller DX5100 Table Top. Quick Start
RMT Ltd.
DX5100 Vision
Install the DX5100 Vision program supplied or downloaded from the manufacturer's website
http://rmtltd.ru/downloads/.
Switch on your 12 V DC power supply. Indicating LED near 12 V DC input wil go red. Apply 12 V
DC to DX5100 interior using 12 VDC switch on DX5100. Indicating LED will go green
Connect the controller to a computer via the cable miniUSB.
By default, the controller has a rate setting of 19200 kbps.
DX 5100 needs one command and one noncommand interface. When you run the program, it
scans the serial ports of the system and determines the command interface of the connected controller
DX5100. Another COM-port is highlighted by colour next to it. This is a noncommand interface. Mark both
the COM-ports and press the button «Open».
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Controller DX5100 - Table Top. Quick Start
Thermistor Settings
Attention! It is strongly recommended to back up the parameters of the controller
before adjusting the thermistor. See "Backup/restore of parameters". DX5100
Vision. Technical Manual.
Procedure Description
Select “Thermistor setting” in DX5100 VISION
The thermistor setting means finding and storing parameters of the ADC channels for each
thermistor in the non-volatile memory.
Thermistor Current Settings
Select the channel you wish to set. It is not necessary to set thermistor in second channel if you
use only one channel of DX5100.
If necessary, you can get the current settings of the thermistor and estimate the accuracy of
measurements. Press the button «Show current Thermistor settings»
The program will read from the controller the type of the function converting resistance to
temperature  = (), and its coefficients, and will try to identify the thermistor. In that case the
coefficients match with the predefined values, the screen will display the following information:
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RMT Ltd.
If the coefficients do not match (the sensor is unknown), the program will build the dependence of
temperature versus resistance to obtain the coefficients and determine the sensor nominal (platinum
sensor at Т = 0 °С, for NTC thermistor at Т = 25°С).
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Controller DX5100 - Table Top. Quick Start
Choice of Thermistor Type
To simplify the setup procedure, the program
offers a choice of predefined characteristics of
thermistors. The list includes parameters for 4
platinum thermistors and 47 NTC thermistors with
different alpha and beta coefficients.
If you have chosen a thermistor from the list,
you can go to the next section, "Calibration of
temperature measurement channel".
If your thermistor is not listed in the menu, you
must use "User defined" option.
The program will ask you to choose a type of
function for calculating temperature and operating
1
temperature range .
Temperature as Function of Resistance:
The controller allows using 2 types of functions for calculating temperature versus resistance:

Polynomial 5th order function:  =  +   +   +   +   +  

Steinhart-Hart equation:


=  +  () +  ()
When Steinhart-Hart equation method is selected, you must enter 3 points of the dependence of
temperature on resistance. This information is
usually provided by a thermistor manufacturer. Two
points should be at the extremes of working range,
while the the third one - in a middle between
extremes. The distance between points must be at
least 10 degrees.
The
Steinhart-Hart
equation
describes NTC thermistors very well.
When choosing a polynomial
function of temperature calculation you must
enter correspondent coefficients, also
available from thermistor manufacturer.
1
The ambient temperature must fall within the operating temperature range, but if you are sure it
does, you can disable the checking of this condition.
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RMT Ltd.
Results of calculations may be checked by clicking
"Calc".
Calibration of Temperature Measurement Channel
Since the calibration procedure of the thermistor in the channel have been carried out by the
manufacturer, you only need to select the thermistor type and nominal:
Click the button «Calibrate». The program will ask for the confirmation:
Double-check parameters and click OK. Then select the calibration mode.
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Controller DX5100 - Table Top. Quick Start
Automatic mode should be chosen. In the automatic mode, the controller will set the parameters
corresponding to your thermistor ;
If necessary, the current settings of the thermistor can be checked and the accuracy of
measurements can be assessed. This procedure is described in the section «Viewing Current Settings
of Thermistor. Checking Measurements.» DX5100 Vision. User Guide.
Using the fields for resistance or temperature inputs in «Check function of approximation»
(upper boxes on a screenshot below), you can check the agreement of the calculated and
experimental values. See the section «Verification of the function of temperature calculation.»
DX5100 Vision. User Guide.
The block «Measurement of the resistance of the thermistor» allows verification of correct
functioning of the temperature measurement channel just by clicking “Measurement”.
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Controller DX5100 Table Top. Quick Start
RMT Ltd.
Setting Alarm Limits
Setting Limits of TEC Voltage
Select correspondent option in DX5100 VISON menu
Important! To prevent a thermoelectric cooler (TEC) failure, it is necessary to set correct
limit values of TEC voltage. Refer to the TEC specifications .
Setting Temperature Limit Values
Select correspondent option in DX5100 VISON menu
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Controller DX5100 - Table Top. Quick Start
The tab "Limiting temperatures" allows to specify the maximum and minimum temperatures. If
temperature is beyond these limits within the time specified, a corresponding alarm is on and channel will
be switched off.
The meaning of the parameters to be set is explained by the following picture.
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Controller DX5100 Table Top. Quick Start
RMT Ltd.
PID Tuning
Select “PID tuning” in “Operation” menu of DX5100 VISION. To fine-tune the PID controller there is
a tab:
Here you can set the PID controller coefficients andplot the setpoint attaining curve at different
values of the coefficients.
Finding of optimum parameters of regulation of the given object is quite a delicate and relatively
long procedure. It is a consecutive experimental tuning of parameters. Details may be found in DX5100
Technical Manual.
Attention! Factory PID settings are just the most common values. Use of the
controller without initial PID check and tune with controller TEC and object may result in
non-proper temperature control and system failure.
To simplify the PID controller optimum parameters choice, in the ТЕС Controller DX5100 the
function auto-PID is realized. We recommend to use auto-PID function for setting PID parameters for the
first time.
This function realizes the known Ziegler-Nichols algorithm.
To run auto-PID, select PID setpoint temperature in menu. Setpoint temperature should be the
same as nominal stabilization temperature of your object. Then click on “AUTO-PID” in the PID Setting
menu. When the process is finished, all coefficients will be displayed in correspondent bars and transient
process will be plotted.
If you are not satisfied by transient process or other issues you can tune PID coefficients further by
yourself. The chapter “PID tuning tips” below describes how different constants affect transients and
overall quality of temperature stabilization. Note the “tips” describe the procedure since the very
beginning. We recommend to play around values obtained by using “auto-PID” procedure, using “start”
and “stop” to check the result of the change.
Attention! Maximum TEC voltage must be set BEFORE starting auto-PID
Attention! Note The manufacturer does not confirm that the parameters obtained using
built-in auto-PID function are the most optimum PID parameters. It is recommended to
check up the obtained parameters and if necessary to carry out a more accurate tuning
of the PID parameters depending on the required quality of the thermal regulation.
PID Tuning Tips
The tuning quality can be estimated by different criteria: by the rate of achieving the setpoint, by the
minimal overshot, by accuracy of setpoint maintenance.
The tuning quality can also be estimation by the transient process of achieving the setpoint.
Recommendations for PID tuning by the form of the starting curve are given below.
1.
Set values of integrated and differential components equal to zero:
Ki=0; Kd=0
Modify the value of the proportional component factor so that the form of the transient process
corresponds to that of curve 2 or 3 (see the figure below).
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Controller DX5100 - Table Top. Quick Start
2. Modify the value of the differential component factor so that the form of the transient process
corresponds to that of curve 2.
Ttarget
T0
3. The integrated component is intended to remove a residual mismatch between the
temperature value achieved in the system and the setpoint. Modify the value of the proportional
component factor so that the form of the transient process correspond to that of curve 3 (one
well-defined relaxion spike with minimum possible oversoot).
Ttarget
T0
The figure below shows results of manual changing of PID coefficients on controller performance.
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RMT Ltd.
Routine Operation
Once ALL setting procedures are completed, DX5100 is ready for routine operation.
As mentioned above, there are following operation modes of DX5100

Regulation is off (idle)

Mode "Program"

T-regulation (relay)

Constant voltage maintenance

PID regulation
Operation modes are briefly described below.
Autostart
Controller allows you to use it in the stand-alone mode (without a computer). Factory setting is
“idle”, but Controller may switches to “Autostart” operation when operation mode is changed from “Idle”.
Object temperature is controlled automatically upon applying of 12 V DC power to DX5100 interior. The
mode required should be selected by using “Boot Mode” tab in DX5100 VISION.
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Controller DX5100 - Table Top. Quick Start
Controlling of indication and regulation.
The main parameters will be displayed on DX5100 display; you can select parameters you wish to
monitor (set and actual temperature in both channels, TEC voltage and current, etc) by using control
buttons, as it is shown on the figure below
R
Rt
L
L
R
0
mode=OFF
1
R
Rt
N
L
R
Rt
N
L
mode=PRG
R
L
L
Pr=Pr-1
Pr=Pr+1
mode=OFF
Rt
R
0
mode=OFF
1
L – left button, single click;
R- right button, single click;
Rt – right button,hold;
Rt
N
L
R
N
Rt
N – no clicks of any button in 5 seconds.
mode=PRG
Pr=Pr-1
Pr=Pr+1
mode=OFF
Schematic illustration of changing parameters indicating by DX5100 display.
Mode "Program"
The Controller has a function "Program" - changing of operation mode in time. This function is
carried out by the programs stored in the non-volatile memory.
For modifying programs of temperature changing in time there is a tab «Program manager».
T-Regulation (Relay)
Immediately after starting this mode, for the fastest possible achievement of the temperature
setpoint, the TEC maximum allowable voltage is supplied. Heating or cooling mode is chosen depending
on the sign of the mismatch of a current temperature and the setpoint. After reaching the setpoint the
TEC is exposed to the stepped voltage equal to the specified value UTreg (can be set by command 26).
Depending on the mismatch (the difference between the setpoint and actual temperature) and on the sign
of the voltage, either UTreg is supplied or 0 volts.
The described process is explained by the figure below.
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RMT Ltd.
T[K]
296
294
292
290
288
286
284
282
Tneed=280K
U[V]
UTECmax=8V
UTreg=2V
0
Constant Voltage
In the mode the TEC constant voltage is maintained in the appropriate polarity.
A User should set a value of constant voltage allowing for a sign. The sign «-» stands for the
heating polarity.
PID regulation (Constant Temperature)
The given mode provides maintenance of constant temperature of an object (TEC). Maintenance of
temperature is carried out by TEC voltage calculated according to PID regulation.
In this mode the voltage value and polarity are controlled. The temperature is controlled within the
allowed limits.
The size of the voltage is controlled and does not exceed the limiting value.
The PID coefficients are set by the User.
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Controller DX5100 - Table Top. Quick Start
Monitoring
The VISION program has the mode of monitoring the controller.
The monitor allows you to monitor a change in time of up to two parameters simultaneously, as well
as a current operating mode.
In addition, you can run and stop any regulation mode.
Choice of parameter
of plot 1
Regulation start and
stop buttons
Monitoring start and
stop buttons
Current value of
parameter of plot 1
Current
value
parameter of plot 2
of
Choice of parameter of plot 2
Modes
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RMT Ltd.
TEC Control: DC versus PWM
Thermoelectric Temperature Controllers (for managing thermoelectric coolers) are usually based
on the PID or PI (proportional–integral–derivative or proportional–integral) regulation mechanism, which is
a control loop feedback generally used in industrial control systems. A PID/PI controller calculates an
"error" value as the difference between a measured process variable and a desired setpoint. The
controlling signals can be various: DC, AC, PWM.
A thermoelectric cooler (TEC) is a DC device. Therefore, when there is a TEC application, AC is
evidently excluded. However TEC supply with the help of pulse-width modulation (PWM) has become
very popular nowadays, as this method is relatively cheaper. Here variable supply may be applied by the
time proportioning form - a period time T and signal amplitude Im are fixed, and variation is achieved by
varying the duty cycle  E.g., a TEC is supplied by the average current I0.
Im
I0

t
T
PWM electric current vs time. I0 – average current, duty cycle is /T
The regulation is achieved as: I 0=f(/T), where T=const. It works well for instance for resistive
heaters, LEDs and others.
However, we should always bear in mind that an alternating current of any nature can be
detrimental to TEC efficiency (temperature difference). It can be easily understood, if we present the input
value (electric current or voltage) in PWM as a superposition of the average and variable values. The
average value results in the thermoelectric cooling, whereas the variable one produces the Joule heating
only.
Pulse-width modulation is compared to DC supply for an example of single-stage 30-pair
thermoelectric cooler.
TEC 1MC06-030-05 Thot=300 K, vacuum
16
70
Pdc
Ppwm(Im=2A)
Ppwm(Im=3A)
Ppwm(Im=4A)
14
60
12
50
40
Power, W
Temperature difference, K
80
DTdc
DTpwm(Im=2A)
DTpwm(Im=3A)
DTpwm(Im=4A)
30
20
10
8
6
4
2
10
0
0
0
1
2
3
4
Electric current, A
a) Temperature dirrefernce vs DC or PWM
average currents
0
10
20
30
40
50
60
70
Temperature difference, K
b) Power consumption to reach temperature
difference by DC or PWM average
currents
Comparison use of DC and PWM supply to TEC operation. TEC type 1MC06-030-05:
PWM with different amplitude currents Im=2, 3, 4 A, duty cycle grows 0…1.
The example illustrates degradation of TEC efficiency if using PWM instead of DC supply. The use of
PWM always gives lower cooling performance of TEC and means always considerable higher power
consumption in comparison with the use of DC supply.
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Controller DX5100 - Table Top. Quick Start
Supply method applicable for TECs without interfering with its operation efficiency is DC. It is true for all
the problems involving TEC operation, as well as TEC control.
Important! The DX5100 Table Top device series is based on DC current for all
operational modes.
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