DX5100 Frame Quick Start

RMT Ltd.
Thermoelectric Module Controller
DX5100-Frame
Quick Start
User Guide
RMT Ltd.
Moscow, 2015
Version 1.04
DX5100-FRAME. Quick Start
RMT Ltd.
Table of Contents
Features and benefits .................................................................................................................................. 3
Specifications .............................................................................................................................................. 3
General .................................................................................................................................................... 3
Performance............................................................................................................................................. 3
Options .................................................................................................................................................... 4
Dimensions .............................................................................................................................................. 5
Thermal mounting considerations................................................................................................................. 6
How to Get Connected ................................................................................................................................. 6
Connection terminals in case of one channel design ................................................................................. 6
Connection terminals in case of two channels design................................................................................ 6
Connector descriptions ............................................................................................................................. 6
TEC Connection ....................................................................................................................................... 7
Thermistor Connection ............................................................................................................................. 7
Power Connection .................................................................................................................................... 8
DX5100 Vision ............................................................................................................................................. 8
Thermistor Settings ...................................................................................................................................... 9
Procedure Description .............................................................................................................................. 9
Thermistor Current Settings ...................................................................................................................... 9
Choice of Thermistor Type ......................................................................................................................11
Temperature as Function of Resistance: ..................................................................................................11
Calibration of Temperature Measurement Channel ..................................................................................12
Setting Alarm Limits ....................................................................................................................................13
Setting Limits of TEC Voltage ..................................................................................................................13
Setting Temperature Limit Values ............................................................................................................14
PID Tuning..................................................................................................................................................16
PID Tuning Tips ......................................................................................................................................16
PID Tuning..................................................................................................................................................18
PID Tuning Tips ......................................................................................................................................18
Operation Modes ........................................................................................................................................20
Autostart .................................................................................................................................................20
Mode "Program" ......................................................................................................................................21
T-Regulation (Relay) ...............................................................................................................................21
PID regulation (Constant Temperature) ...................................................................................................21
Constant Voltage .....................................................................................................................................21
Monitoring...................................................................................................................................................21
Working with LCD and buttons ....................................................................................................................23
TEC Control: DC versus PWM ....................................................................................................................25
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DX5100-FRAME. 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 by one Controlling Board
-
Power channels of two versions: high-power 4Aх8V and low-power 3Aх5V
-
TEC operation current and voltage range as ±4A and ±8V per channel.
-
PID temperature regulation mode
-
Constant voltage operation mode
-
T-Regulation (relay) mode
-
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 RS232 and RS485
-
Networking of up to 32 channels by RS485 bus
-
Software for RS232 and RS485 protocols
-
Protocol WAKE for user software programming
Specifications
General
Name
Units
Value
Comments
Operation Modes
PID
Constant voltage
Temperature Program
Т-regulation (relay)
Yes
Yes
Yes
Yes
Yes
PC control/programming
Stand-alone pre-programmed operation (boot
start)
Yes
USB
RS485
WAKE
32 (128)
Communication interfaces
Communication protocol
Maximum number of channels in network
Programmable thresholds
Temperatures
Max voltage
Operational temperatures range
Storage temperatures range
Humidity
Power supply
TEC bi-directional
(heating and cooling)
°C
°C
%
V
2
1
0…+45
-20…+60
5…95%
12.0+/-10%
BIN & SYM
Combined by RS485
Every Channel
Performance
Maximum current
Maximum voltage
Maximum power
Maximum current
Ver. 1.04. 2015
Name
Units
Value
Absolute Maximum Parameters (Options: Frame 1…4)
A
4
V
8
W
32
Absolute Maximum Parameters (Options: Frame 5, 6)
A
3
Comments
Per channel
Per channel
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DX5100-FRAME. Quick Start
RMT Ltd.
Name
Units
V
W
Value
Maximum voltage
5
Maximum power
15
Regulation channels number
2
Parameters of TEC Voltage Regulation
Voltage Range
V
-8…+8
Voltage Range
V
-5…+5
Accuracy of voltage regulation
mV
1
Resolution of voltage setting
mV
0.13
Measurement resolution
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
Operational modes switch along with
Yes
temperature programming in time
Programs cascading
Yes
Comments
Digital Board
Options: Frame 1…4
Options: Frame 5, 6
Typical values. Depend
on thermistors type
Known T=f(R)
0..15
0..49
Programs in series
All parameters are specified at ambient temperature 23±5°C and humidity 45±15%
Options
The controllers DX5100 Frame are available in six equipment options
Device
Option
Frame 1
Frame 2
Frame 3
Frame 4
Frame 5
Frame 6
Channel
parameters
8V x 4A
8V x 4A
8V x 4A
8V x 4A
5V x 3A
5V x 3A
Number of
channels
1
1
2
2
2
2
Display
module
+
+
+
Frame
type
Low profile
Normal profile
Normal profile
Normal profile
Low profile
Normal profile
Overall
dimensions, mm
126x114x21
126x114x28
126x114x28
126x114x28
126x114x21
126x114x28
Weight,
g
Important! The DX5100 Table Top controller is based on DC current regulation by TEC
in all operational modes for maximum cooling efficiency (See chapter “TEC Control: DC
versus PWM”).
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DX5100-FRAME. Quick Start
Dimensions
Normal profile housing
2
1
6
Frame 2
Frame 3
Frame 4
Frame 6
7
4
5
3
Recommended Airflow Direction
Low profile housing
2
1
Frame 1
Frame 5
4
5
3
1
2
3
4
5
6
7
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Housing base
Cover
Connecting terminals
Power switch
Connector miniUSB
Indicator (LCD Display) (only Frame 2, 4, 6)
Control buttons
(only Frame 2, 4, 6)
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Thermal mounting considerations
The DX5100 FRAME controllers may generate a significant amount of heat. Heat generated must be
adequately removed in order to prevent the controller from overheating. An external heat sink is necessary,
and active air circulation may be required depending on ambient temperature and power supplied to TECs.
Important! Ensure adequate heat dissipation from DX5100 in order to prevent its
overheating .
How to Get Connected
There are connection terminals on one side of the controller. There are two terminal versions, depending on
the number of channels.
Connection terminals in case of one channel design
RS485
A
TEC1
B GND
1 2 3
Rt1
F
4 5 6 7 8 9
S
OUT1
S
INPUT
1
F
10 11 12 13 14 15
12VDC
E
16 17 18 19 20 21 22 23 24 25 26 27
28 29
Connection terminals in case of two channels design
RS485
A
B GND
1 2 3
TEC2
Rt2
F
S
TEC1
S
F
4 5 6 7 8 9
Rt1
F
S
OUT2
S
F
10 11 12 13 14 15
OUT1
2
INPUT
E
1
12VDC
E
16 17 18 19 20 21 22 23 24 25 26 27
28 29
Connector descriptions
Contact #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
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Circuit
Signal A of interface RS485
Signal B of interface RS485
Signal GND of interface RS485
TEC+
TECF+(force) connections to thermistor.
S+(Kelvin sense) connections to thermistor.
S- (Kelvin sense) connections to thermistor.
F- (force) connections to thermistor.
TEC1+
TEC1F+(force) connections to thermistor.
S+(Kelvin sense) connections to thermistor.
S- (Kelvin sense) connections to thermistor.
F- (force) connections to thermistor.
Normally closed contact of the relay Chanel
Common relay Chanel
Normally open contact of the relay Chanel
Normally closed contact of the relay Chanel
Common relay Chanel
Normally open contact of the relay Chanel
Control of channel (digital input)
Common of digital input
Enables to control (digital input)
Control of channel (digital input)
Common of digital input
Notes
RS485
Channel 2
Channel 1
Channel 2
Channel 1
Channel 2
Channel 1
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DX5100-FRAME. Quick Start
Contact #
27
28
29
Circuit
Enables to control (digital input)
Power +
Power -
Notes
Power Supply
TEC Connection
Important! Ensure proper heat dissipation from a hot side of your TEC by using proper
heatsink and good thermal contact between TEC hot side and a heatsink.
Important! Any TEC must be connected according to its polarity to operate in cooling
mode .
Thermistor Connection
Important! The position of temperature sensor (thermistor) must be carefully selected
according to the design of an object (heat load) on a cold side of TEC. The design must
ensure 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 connection 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 (contacts 12-13 and 14-15 in channel 1, contacts 6-7 and
8-9 in channel 2).
TEC
Rt
F
S
TEC
S
F
4 5 6 7 8 9
10 11 12 13 14 15
Rt
F
Channel 2
Channel 1
4-wire connection of thermistor
S
S
F
4 5 6 7 8 9
10 11 12 13 14 15
Channel 2
Channel 1
2-wire connection of thermistor
Connection of TEC and thermistor to the controller
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RMT Ltd.
Power Connection
Connect a power supply observing correct polarity. A power supply source should provide voltage 12±10% V.
Important! Power supply must be chosen basing on total power consumption of the
controller. Power supply must provide at least 80 W output if 2 x 32 W regulation
channels are used at full power. Less powerful supplies may be used otherwise. In any
case, power available from power supply must exceed total power output of both
regulation channels by at least 20%.
DX5100 Vision
You will need a PC to get DX5100 controller up and running when you switch it for the first time. Note you
may not need PC after you stored your programs/settings in DX5100 controller.
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 the program runs, it scans 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. Select both COM-ports and click on «Open».
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DX5100-FRAME. Quick Start
Thermistor Settings
Important! All controllers are set to “Idle” mode before shipment. The controller must
be in “Idle” mode if you set or re-set any parameter. This excludes permanent failures
and fatal damages during the procedure, which are possible otherwise. Check
operation mode carefully before starting any setting or re-setting procedure.
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
The thermistor setting means finding and storing parameters of the ADC channels for each thermistor in the
non-volatile memory.
Thermistor Current Settings
At first, you can check current settings of the thermistor and estimate the accuracy of measurements. Click
on «Show current Thermistor settings»
The program will read the data of thermistor currently set in controller, and will try to identify the thermistor. If
the coefficients match to the predefined (internal library) values, the following information will be displayed:
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If the coefficients do not match to data in internal library (i.e. the sensor is unknown), the program will build the
dependence of temperature versus resistance to obtain the coefficients and determine the sensor nominal).
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DX5100-FRAME. Quick Start
Choice of Thermistor Type
To simplify the setup procedure, the program offers a choice of predefined characteristics of thermistors from
the library. The list includes 4 platinum thermistors and 47 NTC thermistors with different alpha and beta
coefficients.
If the sensor you use is on the list, just select it and go to the next section, "Calibration of temperature
measurement channel".
Otherwise, you must define and set the thermistor data by using "User defined" option. The program will
ask you to choose a type of R(T) function (see below), and operating temperature range. It is important that
normal ambient conditions (usually 25+/-5 oC) are within the range you selected.
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 different values of
temperature and correspondent resistance. This
information is usually provided by a thermistor
manufacturer. Two values should be at the
extremes of working range, while the the third one in a middle between extremes. The difference
between values must be at least 10 K.
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RMT Ltd.
The Steinhart-Hart equation describes NTC thermistors very well.
When choosing a polynomial
function, correspondent coefficients must be
entered, also available from thermistor
manufacturer.
Results of calculations may be checked by clicking "Calc".
Calibration of Temperature Measurement Channel
Click the button «Calibrate». The program will ask for the confirmation:
Double-check parameters and click OK. Then select the calibration mode.
Automatic mode must be chosen. The controller will be preset according to parameters of your thermistor
(either chosen from the list of standard thermistors, or “User defined” as described above).
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DX5100-FRAME. Quick Start
If necessary, the current settings of the thermistor can be checked and the accuracy of measurements can
be assessed. This procedure is described in details in the section «Viewing Current Settings of Thermistor.
Checking Measurements.» DX5100 Vision. User Guide.
Briefly, you can check the agreement of the calculated and experimental values using the fields for
resistance or temperature inputs in «Check function of approximation» (upper boxes on the screenshot
below). The block «Measurement of the resistance of the thermistor» allows more detailed verification of
correct functioning of the temperature measurement channel by clicking on “Measurement”.
Setting Alarm Limits
Setting Limits of TEC Voltage
Select correspondent option in DX5100 VISON menu :
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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.
The tab "Limiting temperatures" allows to specify the maximum and minimum “limit” temperatures. If the
temperature is out of these limits for the time specified, a corresponding alarm is on and the channel is switched off
automatically.
The meaning of the parameters to be set is illustrated by the following picture.
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DX5100-FRAME. Quick Start
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PID Tuning
Select “PID tuning” in “Operation” menu of DX5100 VISION. There is a tab to fine-tune the PID of the
controller as shown below.
Here you can set the PID controller coefficients and check transient process of reaching the setpoint 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 its tuning having your particular TEC and object
(heat load) connected may result in non-proper temperature control and system failure.
Controller DX5100 has “auto-PID” option allowing to simplify the choice of optimum P-I-D finding
considerably. We recommend always use auto-PID for checking/setting of PID parameters for the first time.
The function realizes the 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 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 every change.
Attention! Maximum TEC voltage must be set BEFORE starting auto-PID
Attention! Note the manufacturer does not guarantee the parameters obtained using
built-in auto-PID function are the most optimum. It is recommended to check the
obtained parameters and, if necessary, to carry out 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 Kp so that the form of the transient process
corresponds to that of curve 2 or 3 (see the figure below).
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DX5100-FRAME. Quick Start
Kp1>Kp2>Kp3>Kp4>Kp5
Ttarget
T0
2. Modify the value of the differential component factor Kd so that the form of the transient process
corresponds to that of curve 2.
Ttarget
T0
3. The integrated component Ki 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 corresponds to that of curve 3 (one relaxation spike with minimum
possible overshoot).
Ttarget
T0
The figure below shows an example of results of manual changing of PID coefficients on controller
performance.
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DX5100-FRAME. Quick Start
RMT Ltd.
PID Tuning
Select “PID tuning” in “Operation” menu of DX5100 VISION. There is a tab to fine-tune the PID of the
controller as shown below.
Here you can set the PID controller coefficients and check transient process of reaching the setpoint 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 its tuning having your particular TEC and object
(heat load) connected may result in non-proper temperature control and system failure.
Controller DX5100 has “auto-PID” option allowing to simplify the choice of optimum P-I-D finding
considerably. We recommend always use auto-PID for checking/setting of PID parameters for the first time.
The function realizes the 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 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 every change.
Attention! Maximum TEC voltage must be set BEFORE starting auto-PID
Attention! Note the manufacturer does not guarantee the parameters obtained using
built-in auto-PID function are the most optimum. It is recommended to check the
obtained parameters and, if necessary, to carry out 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.
3.
Set values of integrated and differential components equal to zero:
Ki=0; Kd=0
Modify the value of the proportional component factor Kp so that the form of the transient process
corresponds to that of curve 2 or 3 (see the figure below).
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DX5100-FRAME. Quick Start
Kp1>Kp2>Kp3>Kp4>Kp5
Ttarget
T0
4. Modify the value of the differential component factor Kd so that the form of the transient process
corresponds to that of curve 2.
Ttarget
T0
3. The integrated component Ki 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 corresponds to that of curve 3 (one relaxation spike with minimum
possible overshoot).
Ttarget
T0
The figure below shows an example of results of manual changing of PID coefficients on controller
performance.
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RMT Ltd.
Operation Modes
There are several modes of regulation available by DX5100:





Idle (Regulation is off)
Mode "Program"
T-regulation (relay)
PID regulation
Constant voltage maintenance
To run the device, you should select operation mode first. You should also decide whether you’ll continue to
control DX5100 by PC or not.
If you will continue controlling of DX5100 by a PC, you should simply select operating mode required and
start/stop regulation using VISION ( see “Monitoring” section below).
If you do not plan to use PC further, you should select regulation mode and switch DX5100 to “Autostart”
mode as described below. Temperature regulation will start immediately upon switching on of a DC power supply.
Autostart
DX5100 may be used stand-alone (without a computer) by using “Autostart” option. Factory setting is “idle”,
but controller may be switched to “Autostart” operation when operation mode is changed from “Idle”. In this case,
object temperature will be controlled automatically upon applying of 12 V DC power to DX5100. The mode required
must be selected by using “Boot Mode” tab in DX5100 VISION.
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DX5100-FRAME. Quick Start
Mode "Program"
The Controller may operate programs stored in the non-volatile memory. There is a tab “Program
manager” in VISION for modifying programs of temperature change in time. Please check DX5100 Technical
Manual for more details.
Note no programs are provided by RMT unless agreed before purchase.
T-Regulation (Relay)
Immediately after starting this mode, the TEC maximum allowable voltage is supplied to the TEC for the
most rapid achievement of the setpoint. Heating or cooling mode is chosen depending on the sign of the mismatch
between current temperature and the setpoint. After reaching the setpoint the TEC is exposed to the stepped
voltage equal to the specified value UTreg (see DX5100 Technical Manual for details). Depending on the
mismatch (the difference between the setpoint and actual temperature) and on the sign of the voltage, either UTreg
or 0 volts is supplied.
The described process is explained by the figure below.
T[K]
296
294
292
290
288
286
284
282
Tneed=280K
U[V]
UTECmax=8V
UTreg=2V
0
PID regulation (Constant Temperature)
The given mode provides maintenance of constant temperature of an object (TEC). Maintenance of The
mode provides maintenance of constant temperature of an object (TEC). Maintenance of temperature is carried out
by TEC voltage calculated according to PID regulation. This method provides the most precise temperature
stabilization by TEC.
Both TEC voltage and polarity are automatically controlled in this mode.
The PID coefficients are set by the User as described above.
Constant Voltage
In this mode the TEC constant voltage is maintained. A User should set a value of constant voltage including
the sign. Note the sign «-» stands for the heating polarity.
Monitoring
The mode allows monitoring changes of up to two parameters in time simultaneously, as well as a current
operating mode.
In addition, you can start and stop any regulation mode there. For details, please check the screenshot
below.
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DX5100-FRAME. Quick Start
Choice of parameter of
plot 1
RMT Ltd.
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
Some versions of DX5100 FRAME have a display indicating the main parameters, and two control buttons.
You can select parameters you wish to monitor (set and actual temperature in both channels, TEC voltage and
current, etc) by using these buttons, as it is shown on the figure below. It is important that control buttons may be
used for switching temperature regulation on and off independently on whether DX5100 is controlled by a PC or
not. Please refer DX5100 Technical Manual for more details.
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DX5100-FRAME. Quick Start
Working with LCD and buttons
On the LCD of the board there are the parameters corresponding to a certain mode.
There are 8 screens of indication:
E1
Indication of temperatures and setting values
E5
Device identification
E2
Indication of channel TEC1
E6
Control (launch programm)
E3
Indication of channel TEC2
E7
Set TEC1 setpoint (launch PID)
E4
Status
E8
Set TEC2 setpoint (launch PID)
№
Screen
E1
Description
TEC2 temperature*
TEC1 temperature*
TEC1 setting
TEC1 temperature*
E2
TEC1 setpoint
TEC2 temperature*
E3
TEC2 setpoint
TEC2 setting
channel number
TEC1 regulation
mode**
channel number
TEC2 regulation
mode**
STATUS
Ch1- TEC1 regulation
mode**
Name and version of the
firmware
E4
E5
TEC1 voltage
TEC1 current
TEC2 voltage
TEC2 current
XXXX***
Ch2- TEC2 regulation
mode**
Network address and identifier
Device serial number & Date of release
START Pr-NN
if mode is OFF
E6
STOP
if mode is not OFF
If there is not pressed button for 5 seconds, it will return to
the E2 or E3 screens.
TEC1 temperature*
channel number
TEC1 voltage
E7
TEC2 temperature*
**
setting TEC1
setpoint
TEC1 setpoint
E8
*
(NN= 00…15 program number)
TEC1 if from E2
TEC2 if from E3
TEC2 setpoint
channel number
setting TEC2
setpoint
TEC1 current
TEC2 voltage
TEC2 current
Indication "------" (instead of the temperature) occurs for values of thermistor resistance, exceeding
the maximum for the range, which is configured ADC.
Mnemonic designations are applied for a mode of regulation:
OFF
Regulation is disabled
PRG
According to program
REL
T-regulation (relay)
PID
PID temperature control
VOL
Constant voltage
OK
Temperature is within the setting. The criterion of signal of settling is right (see
command 0x49)
ERR
Ver. 1.04. 2015
Temperature is beyond the limitations (see commands 0x3C 0x3D)
Page 23 / 25
DX5100-FRAME. Quick Start
***
RMT Ltd.
Status displays in hexadecimal. Values status bit:
0x0001
error EEPROM
0x0002
unknown command
0x0004
no ready data for telemetry (response)
0x0008
TEC voltage at Z-metering does not drop for too long
0x0010
error in parameters or command format
0x0020
reception RS-232 buffer overfilling
0x0040
reception RS-485 buffer overfilling
0x0080
voltage supply error
0x0100
TEC1 temperature is beyond the limitations
0x0200
TEC2 temperature is beyond the limitations
0x0400
TEC1 temperature is within the setting
0x0800
TEC2 temperature is within the setting
0x1000
Command performance is interrupted
Since the Firmware version 341 it is possible to set the first (after boot) screen with the command 0x54. Also,
0
using the command 0x54 it is possible to choose unit temperature display - in Kelvin (K) or in degrees Celsius ( ).
Switching between the screens graph illustrates:
To
setpoint
N
2
mode=PID
L
Lt
R
Rt
To=To-1
To=To+1
Lt
R
Rt
L
L
R
1
mode=OFF
L
Lt
R
Rt
0
R
2
N
L
mode=PRG
R
L
L
R
Pr=Pr-1
Pr=Pr+1
mode=OFF
Lt
Rt
To
setpoint
N
2
mode=PID
L
Lt
R
Rt
To=To-1
To=To+1
The graph used the notation:
L – left button, single click;
R- right button, single click;
1
mode=OFF
L
Lt
R
Rt
0
Rt – right button,hold;
Lt – left button,hold;
2 – two buttons click;
N – no clicks of any button in 5 seconds.
Page 24 / 25
2
mode=PRG
N
Pr=Pr-1
Pr=Pr+1
mode=OFF
Ver. 1.04 2015
RMT Ltd.
DX5100-FRAME. Quick Start
TEC Control: DC versus PWM
Thermoelectric Temperature Controllers usually use PID or PI (proportional–integral–derivative or
proportional–integral) regulation for temperature control and stabilization. Such a controller “calculates” an “error
signal” as the difference between measured “actual” temperature (current thermistor value) and a desired setpoint
(preset value). This “error signal” is then used to generate correspondent change of TEC voltage to compensate
the difference between set and current thermistor values.
A thermoelectric cooler (TEC) is a DC device. So DC signals are usually applied to it. However pulse-width
modulation (PWM) is widely used to supply TECs nowadays, as this method is relatively cheaper with respect to
DC modulation. In case of PWM, TEC is powered up by a train of pulses with a fixed period T and amplitude Im, but
with duty cycle changing in time In other words, a TEC is supplied by some “average” effective current I0 which
value changes in time as a function of duty cycle, I0=f(/T).
Im
I0

t
T
PWM electric current vs time. I0 – average current, duty cycle is /T
PWM works well for instance for resistive heaters, LEDs and others.
However, an alternating current of any nature can be detrimental to TEC efficiency (temperature difference).
Let us consider TEC supply (electric current or voltage) in PWM as a superposition of the averaged and fast
variable values. The average value results in the thermoelectric cooling, however, the variable one produces Joule
heating only. This may affect TEC efficiency considerably.
As an example, the figure below illustrates performance of a single-stage 30-pair thermoelectric cooler
1MC06-030-05 (manufacturer – RMT Ltd.) in case of PWM and DC supply.
TEC 1MC06-030-05 Thot=300 K, vacuum
a) Temperature dirrefernce vs DC or PWM
average currents
b) Power consumption to reach temperature
difference by DC or PWM average currents
Comparison of DC and PWM supply of TEC. TEC type 1MC06-030-05 (RMT Ltd.)
PWM with different amplitude currents Im=2, 3, 4 A and duty cycles changed from 0…1 was used.
TEC efficiency degradation in case of PWM is clearly seen. The use of PWM always results in lowering of TEC
performance in cooling mode, and in higher power consumption in comparing to DC supply of TEC.
So we consider DC supply as more efficient than PWM when used for cooling by TECs. This explains why DC
control is used in our DX5100 controllers.
Important! The DX5100-Frame device series is based on DC current for all operational
modes for maximum possible cooling efficiency.
Ver. 1.04. 2015
Page 25 / 25