NPI TC-10 User manual

OPERATING INSTRUCTIONS AND
SYSTEM DESCRIPTION FOR THE
TC-10
TEMPERATURE CONTROL
SYSTEM
VERSION 3.9
npi 2018
npi electronic GmbH, Bauhofring 16, D-71732 Tamm, Germany
Phone [phone]; Fax: [phone]
[email protected]; http://www.npielectronic.com

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Table of Contents
1.Safety Regulations ............................................................................................................ 3
2.TC-10 Components .......................................................................................................... 4
3.TC-10 System ................................................................................................................... 4
3.1.System Description ...................................................................................................... 4
3.2.Description of the Front Panel ..................................................................................... 5
3.3.Rear Panel Elements .................................................................................................... 10
3.4.Electronic Control and Protection Circuits .................................................................. 10
3.5.Modes of Operation ..................................................................................................... 11
3.6.Setting the DESIRED TEMPERATURE .................................................................... 12
4.Grounding ......................................................................................................................... 12
5.Temperature sensors / Block diagram .............................................................................. 13
5.1.DIN Connector ............................................................................................................ 13
5.1.Available sensors ......................................................................................................... 14
5.2.Block diagram ............................................................................................................. 15
6.Operating Guide – Tuning Procedure............................................................................... 16
6.1.Operation with HPT-2A Heated Perfusion Tube (discontinued) ................................ 18
7.Literature .......................................................................................................................... 18
8.Technical Data .................................................................................................................. 19

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1. Safety Regulations
VERY IMPORTANT: Instruments and components supplied by npi electronic are NOT
intended for clinical use or medical purposes (e.g. for diagnosis or treatment of humans),
or for any other life-supporting system. npi electronic disclaims any warranties for such
purpose. Equipment supplied by npi electronic must be operated only by selected, trained
and adequately instructed personnel. For details please consult the GENERAL TERMS
OF DELIVERY AND CONDITIONS OF BUSINESS of npi electronic, D-71732 Tamm,
Germany.
1) GENERAL: This system is designed for use in scientific laboratories and must be operated
by trained staff only. General safety regulations for operating electrical devices should be
followed.
2) AC MAINS CONNECTION: While working with the npi systems, always adhere to the
appropriate safety measures for handling electronic devices. Before using any device
please read manuals and instructions carefully.
The device is to be operated only at 115/230 Volt 60/50 Hz AC. Please check for
appropriate line voltage before connecting any system to mains.
Always use a three-wire line cord and a mains power-plug with a protection contact
connected to ground (protective earth).
Before opening the cabinet, unplug the instrument.
Unplug the instrument when replacing the fuse or changing line voltage. Replace fuse only
with an appropriate specified type.
3) STATIC ELECTRICITY: Electronic equipment is sensitive to static discharges. Some
devices such as sensor inputs are equipped with very sensitive FET amplifiers, which can
be damaged by electrostatic charge and must therefore be handled with care. Electrostatic
discharge can be avoided by touching a grounded metal surface when changing or
adjusting sensors. Always turn power off when adding or removing modules,
connecting or disconnecting sensors, headstages or other components from the
instrument or 19” cabinet.
4) TEMPERATURE DRIFT / WARM-UP TIME: All analog electronic systems are sensitive
to temperature changes. Therefore, all electronic instruments containing analog circuits
should be used only in a warmed-up condition (i.e. after internal temperature has reached
steady-state values). In most cases a warm-up period of 20-30 minutes is sufficient.
5) HANDLING: Please protect the device from moisture, heat, radiation and corrosive
chemicals.

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2. TC-10 Components
The following items are shipped with the TC-10 system:
 TC-10 19” cabinet
 Power cord
 User manual
Optional accessories:
 Miniature temperature sensor (TS-100)
 Subminiature temperature sensor (TS-200)
Caution: The temperature sensors are very sensitive to mechanical stress, especially to bending.
Therefore, they must be handled with great care to avoid breaking of the insulation!
 Recording chamber
 HCS heated chamber stage
 ALA DIN connector cable assembly
 Thermal foil
 Objective heater
 HPC-G perfusion cube
 HPC-2 perfusion cube (low flow rate)
3. TC-10 System
3.1.System Description
The TC-10 temperature control system is designed for heating purposes in electrophysiological
experiments. The TC-10 system is housed in a 19 inch standard cabinet, with a built-in power
supply and cooling elements for the power devices. The TC-10 guarantees low noise operation
and has special protection features to prevent the preparation from damage.
The TC-10 incorporates two electronic thermometers for small semiconductor sensors (R2252,
i.e. the sensor has a resistance of 2252  at 25 °C), two digital temperature displays (XX.X °C),
a set-point control with direct readout (XX.X °C), a PI (proportional-integral) controller with
adjustable parameters, an output power control unit and a high-power output stage (DC,
continuous operation) for resistive (i.e. heat only) loads with electronic protection circuits. The
power output is short circuit protected, the output power is limited electronically. Maximal
output voltage is approximately 12V, the current is limited to 5A.
The system can be connected to the thermistors / heating elements in two ways:
Using separate cables for the sensors and the heating element or
Using the ALA DIN cable assembly that connects both, sensors and heating elements
A large variety of sensors and thermal elements are available (see also Optional accessories in
chapter 2). Please contact npi for details.

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3.2.Description of the Front Panel
Figure 1: TC-10 front panel view

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In the following description of the front panel elements each element has a number that is
related to that in Figure 1. The number is followed by the name (in uppercase letters) written
on the front panel and the type of the element (in lowercase letters). Then, a short description
of the element is given.
(1) DESIRED TEMP./°C potentiometer
Digital potentiometer to set the working temperature of the controller
system.
(2) TEMPERATURE °C A display
Digital display to indicate the temperature determined by SENSOR A or the
voltage at the POWER OUTPUT connectors (18 / 19). Switch (11) is used
to select one of these functions of display A.
(3) ALARM LED
LED to indicate that temperature SENSOR A (13) is not connected, broken or
short-circuited. The POWER OUTPUT (18 / 19) shuts down if this LED is on and
the MODE switch (14) is set to SENSOR A.
(4) GAIN potentiometer
Potentiometer (logarithmic scale) to change the GAIN parameter (amplification
of the error signal, see chapter 3.3) of the temperature controller (PI controller),
range: 10 to .
(5) INTEGRATION potentiometer
Potentiometer to set the INTEGRATION parameter (time constant) of the
temperature controller (PI controller), time range: 50 ms - 20 s.

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(6) TEMPERATURE °C B display
Digital display to indicate the temperature determined by SENSOR B (16).
(7) ALARM LED
LED to indicate that temperature SENSOR B (16) is not connected, broken or
short-circuited. The POWER OUTPUT (18 / 19) shuts down if this LED is on and
the MODE switch (14) is set to SENSOR B.
(8) LIMITER potentiometer
Potentiometer to set the voltage range of the POWER OUTPUT (18 / 19),
100% = 12 Volt.
(9) HEAT LED
LED that indicates the status of the POWER OUTPUT (18 / 19) (LED on = heating).
(10) COMMAND INPUT 10mV/°C connector
BNC connector to set the working temperature of the controller system by an
external voltage signal. This input is scaled with the factor 10mV / °C.

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(11) SENSOR A / PWR OUT switch (display mode switch)
Switch to select the mode of display A (2):
SENSOR A (upper position): the temperature determined by SENSOR A (13) is
displayed (XX.X °C)
PWR OUT ( (lower position): the voltage at the POWER OUTPUT (18 / 19) is
displayed.
(12) OUTPUT A 10mV/°C connector
BNC connector monitoring the temperature determined by SENSOR A (13),
sensitivity: 10mV / °C.
(13) SENSOR A connector
8-pole connector for temperature SENSOR A.
This connector also provides the POWER OUTPUT (18 / 19) for the heating unit
(max. 12V DC and 5A) for devices with the DIN connector cable assembly. (e.g.
HPC-G, see www.alascience.com).
(14) MODE switch
Switch to select the operation modes of the TC-10. Four
modes are available:
SENSOR A: the temperature determined by SENSOR
A (13) is used for the control system
DIRECT: the voltage at the POWER OUTPUT (18 /
19) can be set directly from the DESIRED
TEMPERATURE potentiometer (1) (0-12 V, no control)
EXT. SENSOR (EXTERN SENSOR): an external thermometer connected to BNC (15)
(sensitivity 1mV/°C) can be used for the controller loop
SENSOR B: temperature determined by SENSOR B (16) is used as feedback temperature in
the controller loop.
(15) EXT. SENSOR 1mV/°C connector
BNC connector to connect external thermometer with a voltage output of 1mV/°C
(see also (14)).

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(16) SENSOR B connector
8-pole connector for temperature SENSOR B.
This connector also provides the POWER OUTPUT (18 / 19) for the heating unit
(max. 12V DC and 2.5A) for devices with the DIN connector cable assembly. (e.g.
HPT-2A, see www.alascience.com).
(17) OUTPUT B 10mV/°C connector
BNC connector monitoring the temperature determined by SENSOR B (16),
sensitivity: 10mV / °C.
(18) / (19) POWER OUTPUT Max. 5A DC connectors
Banana jack connectors for the heating unit. This output supplies a
maximum voltage of 12V DC and a maximum current of 5A.
POWER OUTPUT is also available at the SENSOR A (13) and
SENSOR B connectors (16) for devices with the DIN cable assembly.
(20) POWER pressure switch
Switch to turn POWER on (switch pushed) or off (switch released).
(22) Protective earth / (21) GROUND connectors
To avoid ground loops the internal ground of the system is floating, i.e.
it is not connected to the protective earth of the line cable while the
cabinet is always connected via the power supply cable (green / yellow
wire). The system can be grounded by connecting plug (21) protective
earth or (22) internal ground.
(23) SHUTOFF TEMPERATURE label
Label indicating the upper SHUTOFF TEMPERATURE (standard is 60 °C).
If the sensor measures the indicated temperature or more the POWER
OUTPUT is disabled.

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3.3.Rear Panel Elements
LINE VOLTAGE SELECTION: The selector for the line voltage and the connector for the
power cord are located in a mains connection module on the rear panel of the instrument.
Caution: If operated with other line voltage the instrument may be damaged if the wrong line
fuse is installed!
FUSE: The fuse is also integrated in the mains connection module. The line fuse must be 3.15 A
slow (115 V) or 1.6 A slow (230 V). It must be replaced only by specified type (see above).
Please disconnect mains power plug before replacing fuse.
3.4.Electronic Control and Protection Circuits
CONTROL LOOP
The sensor / thermometer, PI-controller, output power stage and heating element form a closed
loop control system. The desired temperature signal is compared with the output signal obtained
from the thermometer giving an error signal. This signal is amplified in the PI controller and
transferred to the output stage where it is converted to a high-power output signal applied to the
heating element.
ELECTRONIC PROTECTION CIRCUITS
Each system is equipped with two protection systems:
1. Sensor inputs: an electronic shut-off function disconnects the output if the sensor is
disconnected, broken or short-circuited.
2. Output protection: the output current and voltage are limited electronically.
Important: The sensor used for the control must be in good thermal connection with the heating
wire, if not, overheating and damage may occur.
ALARM circuit
The internal thermometer (R2252 sensor) inputs are protected by the sensor alarm circuit (see
above). If this thermometer is used as input device for the PI controller, the ALARM circuit
disconnects the power output if the sensor is damaged or not connected. This state is indicated
by the red ALARM LED. If the DIRECT mode or EXT mode is used the ALARM circuit is
disabled.
ACCURACY
Measuring accuracy of the internal thermometer is 0.1°C, controller accuracy is 0.5°C or better
(depending on the amount of heated solution).

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3.5.Modes of Operation
The system can be used in the following modes of operation:
DIRECT MODE: output voltage is set directly by the DESIRED TEMP. °C control.
Internal SENSOR mode: output voltage is controlled by the PI controller using SENSOR A or
SENSOR B.
EXT. SENSOR mode: output voltage is controlled by the PI controller using an external
thermometer.
DIRECT mode
DIRECT mode (no temperature control): the MODE switch (14, Figure 1) is set to the DIRECT
position. The control unit is not active, i.e. the output voltage is preset directly at the DESIRED
TEMP. control ((1, Figure 1). With the setting from 000 to 999 the output voltage increases
linearly from 0 V to 12 V. The ALARM circuit (see below) is disabled in this mode.
The TC-10 is designed with an unipolar output (0-12 Volt DC). If a resistive load is used, the
system can be used for heating purposes in all modes (SENSOR and DIRECT).
Internal SENSOR mode
In this mode the output voltage is controlled by the PI controller (PI [proportional-integral
controller system] activated). The temperature signal which is used for the control unit is
selected by the MODE switch.
 The SENSOR A or SENSOR B position selects one of the internal thermometers
(SENSOR A or SENSOR B) which use a small semiconductor sensor. The measured
temperature is shown at the respective digital display unit (2 or 6, Figure 1 respectively,
XX.X °C).
 If no sensor is connected or if the sensor is damaged or short circuited the internal shut-
off unit disconnects the power output. This state is indicated by the red ALARM LED
(3 or 7, Figure 1 respectively) located just above the sensor connectors.
Caution: The temperature sensors are very sensitive to mechanical stress, especially to bending.
Therefore, they must be handled with great care to avoid breaking of the insulation!
EXT. SENSOR mode
This mode can be used to connect an external thermometer. The calibration of the external input
(SENS. INPUT BNC, (15, Figure 1)) is 1 mV / °C. If this option is used the internal ALARM
circuit is disabled.
POWER OUTPUT is always available at POWER OUTPUT, SENSOR A and SENSOR B
connectors.
Caution: Do not operate heating devices with too much voltage! Refer to the respective manual
of the device for maximum voltage allowed, and use the LIMITER (8) when necessary!!

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3.6.Setting the DESIRED TEMPERATURE
There are two ways to set the DESIRED TEMPERATURE:
1. The easiest way is to use the digital potentiometer DESIRED TEMP. / °C. The
temperature can be set from +03.0 °C to +60.0 °C, resolution: 0.1 °C. If the TC-10
leaves this temperature window the internal shut-off unit disconnects the power output.
This could be the case if the sensor is broken or short-circuited.
2. If the user wants to have external control (e.g. with a computer system) the DESIRED
TEMPERATURE can be set using the COMMAND INPUT 10mV / °C connector (10,
Figure 1). The COMMAND INPUT is scaled 10mV / °C, i.e. +370 mV at this connector
would set the DESIRED TEMPERATURE to +37 °C.
Important: The set value of the temperature is always the sum of the setting at DESIRED
TEMP. / °C potentiometer and the voltage at COMMAND INPUT 10mV / °C connector, i.e. if
DESIRED TEMP. / °C is set to +25.0 °C and the voltage at COMMAND INPUT 10mV / °C is
+150 mV the temperature will be set to +40 °C !!
Figure 5 gives an overview of the operation modes of the TC-10.
4. Grounding
To avoid ground loops the internal ground of the system is floating, i.e. it is not connected to
the protective earth of the line cable while the cabinet is always connected via the power supply
cable (green / yellow wire). The system can be grounded by connecting plug 21, Figure 1
(protective earth) or 22, Figure 1 (internal ground).

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5. Temperature sensors / Block diagram
5.1.DIN Connector
Figure 2: How to connect the temperature sensor

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Figure 3: Connector pinout of the DIN connector (pins 1 and 3 are connected internally)
5.1.Available sensors
Figure 4: Temperature sensors and cable.
The sensors come with a connection cable (TS-CAB, see Figure 4, left) with a DIN connector
on one end and two 1 mm connectors on the other end. The DIN connector is for connection to
the SENSOR input at the front panel of the temperature controller. The 1 mm connector are for
connection of the sensor, which is available as spare part.
There are two sensors available: the white TS-100S (Figure 4 right, top) and the dark TS-200S
(Figure 4 right, bottom).
Important: The TS-100S has a special coating that makes it mechanically stable and
waterproof. The TS-200S is optimized for size. Its coating might get leaky after mechanical
stress (e.g. bending of the wires).
Dimensions:
TS-100S: 2.5 mm x 6 mm
TS-200S: 0.8 mm x 6 mm

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5.2.Block diagram
Figure 5: Block diagram of the TC-10

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6. Operating Guide – Tuning Procedure
After unpacking the instrument please check the appropriate voltage at the voltage selector at
the back panel. Also check that the sensor used for the control is in good thermal connection
with the heating wire.
Important: Make sure that the SENSOR or the external SENSOR, respectively, and the heating
device that is controlled by this SENSOR are using the same channel. Otherwise the heating
device may be damaged due to overheating.
In the following it is assumed that you use heating devices delivered by npi or ALA Scientific
Instr. with 12V operating voltage. Please follow these instructions step by step to avoid
problems in adjusting the instrument.
 Turn all potentiometers to the most left position
 switch the MODE selector to the position SENSOR A or B depending on which sensor
is used as feedback temperature in the controller loop
 set the DESIRED TEMPERATURE to e.g. 37 °C
 turn on the instrument and wait at least 15 minutes to warm up the instrument. The
temperature display should show the actual temperature at the sensor
 turn the LIMITER to 100%
Note: If you use heating wires with 6V operating voltage turn the LIMITER to 50% to
protect the wire from damage.
If the difference between the actual and the desired temperature is more than 10 °C the
HEAT-LED will light up slightly.
 turn the GAIN to the seventh scale mark
The actual temperature at the sensor now approaches the desired temperature but will not reach
37 °C, because the control loop is not yet well adjusted. The actual temperature will arrest at 1
to 2 °C below the desired temperature. Please wait until this steady state value is reached. This
may last several minutes. If you don’t get a steady state value, set the LIMITER to 80-90% (or
30-40%, respectively) and wait again.

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 Now turn on the INTEGRATION and set it approximately to the first scale mark. You
will hear a “Click” if the INTEGRATION gets active.
 The actual temperature at the sensor will now reach the desired temperature possibly
after a small overshoot. Wait again until the steady state value is reached. If this value
is not reached set the GAIN to higher levels until - in this example - 35 °C to 35.5 °C is
reached.
 If the desired temperature is not reached first set the GAIN to a slightly higher level and
then – if necessary – raise the INTEGRATION (see Figure 6).
Note: The speed of the control circuit (and therefore the time in which the actual temperature
reaches the DESIRED TEMPERATURE) is highly dependent on the first settings of GAIN and
INTEGRATION. Thus, when beginning to use the TC-10 we recommend to try out several first
settings of GAIN and INTEGRATION to find out which settings are best for your experimental
conditions.
If you use a perfusion system it is recommended to heat the solution approximately to the
desired temperature before perfusing the bath either with a heated perfusion tube (HPT-2A,
available from npi) or by heating up the supplying bowl.
As mentioned above it is very important that the sensor element and the heating element are in
good thermal connection.
In Figure 6 the time course of temperature regulation of the TC-10 is shown. As resistive load
a bulb (12V, 21W) was used. The temperature sensor was fixed directly on the bulb and sensor
and bulb were wrapped with foam. Starting temperature was 27,3 °C. Starting conditions were:
LIMITER set to 0, GAIN set to 0, INTEGRATION off.
Figure 6: Time course of temperature regulation of the TC-10.
1: LIMITER was set to 100%, GAIN was set to the seventh scale mark
2: GAIN was set to the eighth scale mark
3: INTEGRATION was turned on at a low level
25
27
29
31
33
35
37
39
0 100 200 300 400 500 600 700 800 900 1000
temperature (°C)
time (s)
1
2
3

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6.1.Operation with HPT-2A Heated Perfusion Tube (discontinued)
For use with HPT-2A from ALA please follow these hints.
 Always use the LIMITER. Do not set the LIMITER to more than 50% for a longer time,
since the HPT-2A will melt if operated at more than 5V. If in doubt, measure the output
voltage using a voltmeter.
 Do not heat the HPT-2A without flow of solution. See also HPT-2A manual.
7. Literature
Kettenmann, H. and R. Grantyn (eds.) Practical Electrophysiological Methods,
Wiley-Liss, New York 1992
Froehr, F. and F. Orttenburger Introduction to Electronic Control Engineering,
Siemens AG, Berlin and Munich 1982

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8. Technical Data
Sensor input: for semiconductor 2252  at 25 °C (standard) or platinum
100  at 0 °C, accuracy typically 0.1 °C at 25 °C, with
electronic protection
Sensor input (EXT. Mode): 1 mV / °C
ALARM and SHUTOFF: disconnects POWER OUTPUT if temperature is below
+3 °C (not connected or broken sensor) or above +60 °C
(short circuited sensor); other ranges possible
Digital displays: 3 1/2 digits, XX.X °C (temperature of SENSOR A or B) or
XX.X V (voltage at power output)
COMMAND INPUT: analog input, 10 mV / °C, via BNC connector
Set value control: digital control, range: up to 60.0 °C (other value possible),
XX.X °C or 0-100% of output voltage (DIRECT mode)
Temperature OUTPUT (A, B): analog outputs, 10mV / °C, via BNC connector, output
impedance: 250 
Power output: max. 12 V / 5 A, short circuit protected, continuous DC
Limiter: control for the output voltage with a linear range from
0 – 100 %
Control: PI (proportional-integral) controller, accuracy typically
±0.2 °C, gain range 10-10k, integration time 50 ms - 20 s
(logarithmic scale)
Measuring accuracy: 0.1 °C at 25 °C
Power requirements: 115 / 230V AC, 60 / 50 Hz, fuse 3.15 / 1.6 A slow
Dimensions: 19” rackmount cabinet 19” (483 mm), 10” (250 mm),
3.5” (88 mm)