SRS Labs PTC10 User Manual
Version 4.2 (May 14, 2019)
User Manual
PTC10
Programmable Temperature Controller
PTC10 Programmable Temperature Controller
Certification
Stanford Research Systems certifies that this product met its published specifications at the time of shipment.
Warranty
This Stanford Research Systems product is warranted against defects in materials and workmanship for a period of
one (1) year from the date of shipment.
Service
For warranty service or repair, this product must be returned to a Stanford Research Systems authorized service
facility. Contact Stanford Research Systems or an authorized representative before returning this product for repair.
Information in this document is subject to change without notice.
Copyright © Stanford Research Systems, Inc., 2018. All rights reserved.
Stanford Research Systems, Inc.
1290-C Reamwood Avenue
Sunnyvale, California 94089
Phone: (408) 744-9040
Fax: (408) 744-9049
www.thinkSRS.com
Printed in the USA
Contents i
PTC10 Programmable Temperature Controller
Contents
Safety and preparation for use....................................................................................... v
Specifications .................................................................................................................. vii
Introduction 1
I/O cards ............................................................................................................................ 2
PTC320 thermistor/diode/RTD card .................................................................................... 2
PTC321 RTD reader ................................................................................................................ 5
PTC323 2-channel thermistor/diode/RTD card ................................................................... 6
PTC330 thermocouple reader .............................................................................................. 11
PTC420 AC output card........................................................................................................ 13
PTC430 50 W DC output card ............................................................................................. 14
PTC431 100W DC output card ............................................................................................ 15
PTC440 TEC driver ............................................................................................................... 17
PTC510 analog I/O card ....................................................................................................... 20
PTC520 digital I/O card ........................................................................................................ 20
Operation 23
Quick start tutorial ........................................................................................................ 24
Turn the instrument on .......................................................................................................... 24
The Select screen ................................................................................................................... 24
Configure the sensor inputs ................................................................................................... 24
If the sensor reading does not appear ................................................................................... 25
Plot data .................................................................................................................................. 25
Test the outputs ..................................................................................................................... 26
Set the data logging rate ......................................................................................................... 27
Save data to and retrieve data from a USB memory device ................................................ 27
Interface with a computer ...................................................................................................... 28
Control a temperature........................................................................................................... 29
Acquiring and logging data ........................................................................................... 36
Input filters .............................................................................................................................. 36
Custom calibration tables ...................................................................................................... 36
Virtual channels ...................................................................................................................... 38
Logging data to internal memory ........................................................................................... 39
Logging data to USB ............................................................................................................... 39
ADC sampling and logged data ............................................................................................. 39
Format of PTC10 log files ...................................................................................................... 40
Using the system fan ..................................................................................................... 41
Using PID feedback ........................................................................................................ 42
...................................................................... 42
Basic PID feedback concepts ................................................................................................. 42
Manual tuning .......................................................................................................................... 43
Automatic tuning algorithms .................................................................................................. 46
Using the automatic tuner...................................................................................................... 49
Front-panel controls ................................................................................................ ...... 52
Contents ii
PTC10 Programmable Temperature Controller
USB logging indicator ............................................................................................................. 52
.............................................................................................................................. 52
.............................................................................................................. 52
....................................................................................................................... 53
.................................................................................................................. 54
........................................................................................................................... 54
................................................................................................................... 59
................................................................................................................... 64
..................................................................................................................... 78
Firm ware updates .......................................................................................................... 85
Replacing the clock battery .......................................................................................... 86
Remote programm ing 87
Connecting to the PTC10 ...................................................................................................... 87
Communication, assembly, and run-time errors .................................................................. 90
Concurrent macros ................................................................................................................ 90
Macro names .......................................................................................................................... 91
Command syntax ................................................................................................................... 91
Rem ote instructions ...................................................................................................... 95
General instructions ............................................................................................................... 95
IEEE 488.2 Instructions ........................................................................................................... 99
Program submenu ................................................................................................................ 103
System submenu ................................................................................................................... 106
<channel> submenu ............................................................................................................ 110
Error codes ........................................................................................................................... 121
Startup macro ....................................................................................................................... 122
Sam ple m acros ............................................................................................................. 123
Temperature profiles ........................................................................................................... 123
Control a feedback setpoint with an analog input .............................................................. 124
PID input scheduling ............................................................................................................. 124
Show channels with tripped alarms on the Numeric screen ............................................. 125
Make a virtual channel show the PID setpoint ................................................................ .... 125
Linearizing outputs when interfacing with external power supplies .................................. 125
Control instrument functions with the digital IO lines ....................................................... 126
Drive a solid state relay with the digital IO lines ................................................................. 127
PC applications 129
PTCFileConverter ....................................................................................................... 130
FileGrapher ................................................................................................................... 132
File menu ................................ ............................................................................................... 132
Edit menu .............................................................................................................................. 132
Process menu ....................................................................................................................... 134
Special menu ......................................................................................................................... 136
Command line and macro instructions ............................................................................... 137
Circuit description 141
Core system cards ....................................................................................................... 142
PTC212 CPU board ............................................................................................................. 142
PTC221 backplane ............................................................................................................... 142
Contents iii
PTC10 Programmable Temperature Controller
PTC231 front panel .............................................................................................................. 144
PTC240 GPIB card ............................................................................................................... 145
I/O cards ........................................................................................................................ 146
PTC320 1-channel thermistor/diode/RTD reader ........................................................... 146
PTC321 4-channel RTD reader ........................................................................................... 147
PTC330 thermocouple reader ............................................................................................ 148
PTC420 AC output card...................................................................................................... 149
PTC430 50W DC output card ............................................................................................ 149
PTC431 100W DC output card .......................................................................................... 150
PTC440 TEC driver ............................................................................................................. 151
PTC510 analog I/O card ..................................................................................................... 152
PTC520 digital I/O card ...................................................................................................... 153
Parts List 155
PTC212 CPU board ............................................................................................................. 155
PTC221 backplane ............................................................................................................... 165
PTC231 front panel .............................................................................................................. 167
PTC240 GPIB option ........................................................................................................... 169
PTC320 1-channel thermistor, diode, and RTD reader .................................................... 170
PTC321 4-channel RTD reader ........................................................................................... 173
PTC330 thermocouple reader ............................................................................................ 176
PTC420 AC output card...................................................................................................... 180
PTC430 50W DC output card ............................................................................................ 182
PTC440 TEC driver ............................................................................................................. 184
PTC510 analog I/O card ..................................................................................................... 187
PTC520 digital I/O card ...................................................................................................... 189
Schematics 193
Safety and Preparation for Use v
PTC10 Programmable Temperature Controller
Line voltage
The PTC10 operates from an 88 to 264 VAC power source having a line frequency between 47
and 63 Hz.
Power entry module
A power entry module, labeled AC POWER on the back panel of the PTC10, provides
connection to the power source and to a protective ground.
Power cord
The PTC10 package includes a detachable, three-wire power cord for connection to the power
source and protective ground.
The exposed metal parts of the box are connected to the power ground to protect against
electrical shock. Always use an outlet which has a properly connected protective ground. Consult
with an electrician if necessary.
Grounding
A chassis grounding lug is available on the back panel of the PTC10. Connect a heavy duty
ground wire, #12AWG or larger, from the chassis ground lug directly to a facility earth ground to
provide additional protection against electrical shock.
Line fuse
Use a 10 A/250 V 3AB Slo-Blo fuse.
Operate only with covers in place
To avoid personal injury, do not remove the product covers or panels. Do not operate the
product without all covers and panels in place.
Serviceable parts
The PTC10 does not include any user serviceable parts inside. Refer service to a qualified
technician.
Specifications vii
PTC10 Programmable Temperature Controller
PTC10 temperature controller
Maximum PID rate 50 or 60 Hz, depending on AC line frequency
Data logging rate 10 samples/second/channel 1 sample/hour/channel (can be set
independently for each channel or globally for all channels)
Display resolution 0.001 °C, °F, K, V, A, W, etc. if 1000 < displayed value < 1000;
6 significant figures otherwise
PID feedback auto-tuning Single step response or relay tuning with conservative, moderate, and
aggressive response targets
Display 320 × 240 pixel touchscreen; numeric and graphical data displays.
Alarms Upper and lower temperaturelimits or rate-of-change limits can be set on each
channel. If exceeded, an audio alarm and a relay closure occur.
Computer interface USB, Ethernet, and RS-232; optional GPIB (IEEE488.2)
Power 10 A, 88 to 132 VAC or 176 to 264 VAC, 47 to 63 Hz or DC
Dimensions 17"× 5" × 18" (WHL)
Weight 25 lbs.
Warranty One year parts and labor on defects in material and workmanship.
PTC320 thermistor, diode, and RTD reader
Inputs One input for 2-wire or 4-wire thermistor, diode, or RTD
Connector 6-pin 240° push-pull DIN socket
Thermistors
Range 0 30, 100, 300 ; 1, 3, 10, 30, 100, 300 k ; 2.5 M
Excitation current
30 range 200 µA
100 range 100 µA
300 range 50 µA
1 k range 30 µA
3 k range 20 µA
10 k range 10 µA
30 k range 5 µA
100 k range 3 µA
300 k range 2 µA
2.5 M range 1 µA
Initial accuracy
30 range ±0.025
100 range ±0.06
300 range ±0.1
1 k range ±0.2
3 k range ±0.6
10 k range ±1.3
30 k range ±4
100 k range ±10
300 k range ±250
2.5 M range ±30 k
Drift due to temperature
30 range ±0.002 /°C
100 range ±0.006 /°C
300 range ±0.006 /°C
1 k range ±0.01 /°C
Specifications viii
PTC10 Programmable Temperature Controller
3 k range ±0.03 /°C
10 k range ±0.1 /°C
30 k range ±0.15 /°C
100 k range ±0.5 /°C
300 k range ±3 /°C
2.5 M range ±2000 /°C
RMS noise
30 range 0.003
100 range 0.006
300 range 0.012
1 k range 0.02 (= 2 mK for 300 thermistor at 25°C)
3 k range 0.03 (= 0.8 mK for 1 k thermistor at 25°C)
10 k range 0.06 (= 0.6 mK for 2252 thermistor at 25°C)
30 k range 0.1 (= 0.3 mK for 10 k thermistor at 25°C)
100 k range 0.3 (= 0.2 mK for 30 k thermistor at 25°C)
300 k range 3 (= 0.7 mK for 100 k thermistor at 25°C)
2.5 M range 25 (= 1.8 mK for 300 k thermistor at 25°C)
Diodes
Excitation current output 10 µA
Initial accuracy ± 100 ppm
Drift ±5 ppm/°C
Voltage input 0 2.5 V
Initial accuracy 10 µV + 0.01% of reading
Drift ±5 ppm/°C
RMS noise 1.5 µV
RTDs
Range 0 30, 100, 300 ; 1, 3, 10, 30, 100, 250 k , 2.5 M
Excitation
30 range 3 mA
100 range 2 mA
300 range 1 mA
1 k range 500 µA
3 k range 200 µA
10 k range 100 µA
30 k range 50 µA
100 k range 10 µA
300 k range 5 µA
2.5 M range 1 µA
Initial accuracy
30 range ±0.004
100 range ±0.008
300 range ±0.02 (=±50 mK for Pt100 RTD at 25°C)
1 k range ±0.04
3 k range ±0.1
10 k range ±0.2
30 k range ±1
100 k range ±2.5
300 k range ±16
2.5 M range ±30 k
Drift due to temperature
30 range ±0.0006 /°C
100 range ±0.001 /°C
300 range ±0.0015 /°C (=±5 mK/°C for Pt100 RTD at 25°C)
1 k range ±0.005 /°C
3 k range ±0.01 /°C
10 k range ±0.03 /°C
Specifications ix
PTC10 Programmable Temperature Controller
30 k range ±0.06 /°C
100 k range ±0.2 /°C
300 k range ±3 /°C
2.5 M range ±2000 /°C
RMS noise
30 range 0.00012
100 range 0.0003
300 range 0.0006 ( = 1.4 mK for Pt100 RTD at 25°C)
1 k range 0.0013
3 k range 0.003
10 k range 0.006
30 k range 0.012
100 k range 0.07
300 k range 0.25
2.5 M range 25
PTC321 Pt RTD reader
Inputs Four 4-wire inputs for 100 Pt RTDs
Connector 5-pin, 3.5mm header
Range 0 400
IEC751 Pt100 RTDs 215 °C to 850 °C
Excitation current 1 mA
Initial accuracy ±30 mK
Drift due to temperature 1.4 mK/°C
Drift due to time ±15 mK/year (at 25°C ambient temperature)
Noise 2 mK RMS (at 25°C sensor temperature and 10 samples/s)
Signal detection Card detects open and short circuit conditions
PTC323 thermistor, diode, and RTD reader
Inputs Two inputs for 4-wire thermistor, diode, or RTD
Connectors One 9-pin D-sub socket
RTDs and thermistors
Range 0 10, 30, 100, 300 ; 1, 3, 10, 30, 100, 300 k ; 2.5 M , or auto
Excitation current Low power High power
10 range 1 mA 3 mA
30 range 300 µA 3 mA
100 range 100 µA 2 mA
300 range 30 µA 1 mA
1 k range 10 µA 500 µA
3 k range 3 µA 200 µA
10 k range 1 µA 50 µA
30 k range 300 nA 50 µA
100 k range 100 nA 5 µA
300 k range 30 nA 5 µA
2.5 M range 1 µA 1 µA
Initial accuracy (AC current, at midrange)
10 range ±0.007 ±0.005
30 range ±0.03 ±0.005
100 range ±0.07 ±0.008
300 range ±0.25 ±0.015 (=±40 mK for Pt100 RTD at 25°C)
1 k range ±0.6 ±0.05
3 k range ±2 ±0.1
Specifications x
PTC10 Programmable Temperature Controller
10 k range ±6 ±0.25
30 k range ±25 ±1
100 k range ±150 ±4
300 k range ±1 k ±13
2.5 M range ±3 k ±3 k
Typical drift due to temperature (at midrange)
10 range ±0.0002 /°C ±0.0001 /°C
30 range ±0.0004 /°C ±0.0001 /°C
100 range ±0.002 /°C ±0.0002 /°C
300 range ±0.004 /°C ±0.0004 /°C
1 k range ±0.01 /°C ±0.001 /°C
3 k range ±0.06 /°C ±0.003 /°C
10 k range ±0.2 /°C ±0.01 /°C
30 k range ±1 /°C ±0.02 /°C
100 k range ±3 /°C ±1 /°C
300 k range ±20 /°C ±2 /°C
2.5 M range ±30 /°C ±50 /°C
RMS noise (DC current, at midrange)
10 range 0.0003 0.0001
30 range 0.001 0.0001
100 range 0.002 0.0002
300 range 0.006 0.0003 ( = 0.8 mK for Pt100 RTD at 25°C)
1 k range 0.02 0.0007
3 k range 0.06 0.002
10 k range 0.2 0.007
30 k range 1.0 0.008
100 k range 6 0.12
300 k range 40 0.2
2.5 M range 10 10
Diodes
Excitation current output 10 µA
Initial accuracy ± 100 ppm
Drift ±5 ppm/°C
Voltage input 0 2.5 V
Initial accuracy 10 µV + 0.01% of reading
Drift ±5 ppm/°C
RMS noise 3 µV
PTC330 thermocouple reader
Inputs Four optoisolated thermocouple inputs
Connector Mini thermocouple jacks
Thermocouple types E, J, K, N, or T
Range ±500 mV
Type E 270 °C to 980 °C (range of calibration table with cold junction at 25°C)
Type J 210 °C to 1177 °C
Type K 270 °C to 1342 °C
Type N 270 °C to 1281 °C
Type T 270 °C to 383 °C
Input capacitance <1 pF
Accuracy ±500 mK (over 12 months)
Noise 20 mK RMS (at 10 samples/s)
Drift due to temperature 20 mK/°C (type K thermocouple at 164.0 K)
CMRR 100 dB
Common mode isolation 250 VAC
Specifications xi
PTC10 Programmable Temperature Controller
PTC420 AC output card
Output One line voltage output switched by solid-state relay
Connector NEMA 5-15 (3-prong North American wall socket); a heater cable with a
mating plug on one side and stripped ends on the other is included
Output voltage 120/240 VAC
Max. output current 5 A
On/off cycle time Adjustable between 1 and 240 s
Max. line voltage 250 VAC
Surge current 100 A max. (non-repetitive)
Output resolution 0.1% at 10 s cycle time
Heater resistance (min.) 24 (110 VAC), 46 (230 VAC)
PTC430 50 W DC output card
Output One linear, unipolar DC current source
Connector Two banana jacks, 0.75 inch center-to-center spacing
Range 50 V 1A, 20 V 2 A, 50 V 0.5A, 20 V 0.5 A,50 V 0.1A, or 20 V 0.1 A
Output resolution 24 bits with dithering enabled or 16 bits with dithering disabled
Accuracy ±1 mA (1 A range)
±0.1 mA (0.5 A range)
±0.01 mA (0.1 A range)
Noise (rms), 50 load, 6 µA (50 V 1 A and 20 V 2 A ranges)
DC 10 Hz 1.5 µA (0.5 A range)
0.2 µA (0.1 A range)
PTC431 100W DC output card
Output One unipolar DC current source
Connector #6 screw terminals. Accepts 12 22 AWG wire or #6 spade terminals up to
-lb.
Range 50 V 2A, 50V 0.6A, 50V 0.2A, 20V 2A, 20V 0.6A, 20V 0.2A
Output resolution 16 bits
Accuracy ±1 mA (2 A range)
±0.5 mA (0.6 A range)
±0.2 mA (0.2 A range)
Noise (rms), 25 load, 5 µA (2 A range)
DC 10 Hz 1.5 µA (0.6 A range)
0.5 µA (0.2 A range)
PTC440 TEC driver
Output One linear, bipolar DC current source
Input One 2- or 4-wire thermistor/RTD/IC temperature sensor input
Connector One 15-pin DB15-F
TEC driver
Output current -5 A +5A
Maximum power 50W
Compliance voltage 12 V (at 0 A current)
Output resolution 0.15 mA
Accuracy ±5 mA
Current noise 0.02 mA (at 0.5A current, 22 ohm resistive load, 0.01-10 Hz bandwidth)
Specifications xii
PTC10 Programmable Temperature Controller
Temperature sensor input
Compatible sensors
Thermistors 2 or 4-wire NTC thermistors
RTDs 4-wire platinum RTDs, 100 1000 at 0°C
IC sensors LM335, AD590, or equivalent
Excitation current 10 µA, 100 µA, or 1 mA
Input range
Resistance 1 250 k
Voltage 0 2.5V
Current 0 1 mA
RMS electronic noise (sensor at 25°C)
10 µA excitation
1 k thermistor 0.7 = 15 mK
2252 thermistor 0.6 = 5 mK
10 k thermistor 1 = 4 mK
100 µA excitation
1 k thermistor 0.1 = 1.5 mK
2252 k thermistor 0.1 = 0.7 mK
10 k thermistor 0.2 = 0.5 mK
1 mA excitation
100 Pt RTD 0.003 = 8 mK
LM135/235/335 4 mK RMS
AD590/592 6 mK RMS
Initial accuracy
10 µA excitation
1 k thermistor 1.2 = 30 mK
2252 thermistor 10 = 100 mK
10 k thermistor 66 = 150 mK
100 µA excitation
1 k thermistor 0.06 = 1.6 mK
2252 k thermistor 0.1 = 10 mK
10 k thermistor 0.5 = 1.1 mK
1 mA excitation
100 Pt RTD 0.004 = 5 mK
LM135/235/335 70 mK
AD590/592 400 mK (sensor at 25°C)
Thermal drift
10 µA excitation
100 µA excitation
1 mA excitation
LM135/235/335
AD592/592
Analog I/O
Inputs/outputs 4 voltage I/O channels, independantly configurable as inputs or outputs
Connector 4 BNC jacks
Range ±10 V
Resolution 24-bit input, 16-bit output
ADC noise 30 µV RMS = 100 µV p-p (10 samples/s)
Digital I/O
Digital I/O
Inputs/outputs 8 optoisolated TTL lines, configurable as either 8 inputs or 8 outputs
Specifications xiii
PTC10 Programmable Temperature Controller
Connector One DB-25F
Relays
Outputs 4 independent SPDT relays
Connector One 12-pin 3.5mm header
Maximum current 5 A
Maximum voltage 250 VAC
Introduction 1
PTC10 Programmable Temperature Controller
Introduction
The PTC10 is a high-performance, general-purpose laboratory temperature controller that can
monitor and control temperatures with millikelvin resolution. Its features include:
Modular design
The PTC10 can accept up to four I/O cards, each of which can read up to four temperature
sensors and/or drive one heater. The instrument can be customized by selecting the I/O cards best
suited to your application. The PTC10 also comes standard with four ±10V I/O channels that can
be used with external amplifiers to read signals and drive heaters.
Reads up to 16 tem perature sensors
Temperature input cards are available for reading thermocouples, RTDs, thermistors, and
diodes. For optimal signal-to-noise ratio, each temperature input channel has its own 24-bit ADC.
Drives up to 6 heaters
Three kinds of heater driver cards are available for driving resistive heaters and thermoelectric
devices. Depending on the model of driver card used, two or three heaters can be directly driven at
full power. In addition, the unpowered voltage I/O channels included as standard equipment can
be used to drive heaters with the help of an external amplifier.
Graphical touchscreen display
The PTC10 can display temperature measurements and heater output on graphs or numeric
displays. Any combination of channels can be displayed, and four different channel combinations
can be saved and recalled. Touchscreen operation makes the instrument versatile and easy to use.
Logs data to USB memory devices
Up to 10 data points/second/channel can be logged to standard USB memory sticks and hard
drives. The data can be transferred to a computer by simply plugging the USB device into a PC and
copying the log files. Windows applications are included to graph PTC10 log files and to convert
them to various ASCII text formats.
Up to 6 feedback loops
The PTC10 can control up to six different temperatures (one for each heater output) by
continually adjusting the amount of power supplied to heaters. Each feedback loop can run as fast as
50 or 60 Hz, depending on the frequency of your AC power.
Runs user programs
A macro programming language makes it possible to customize the functionality of the
instrument. Conditional statements, variables, and subroutine calls are supported. Up to 10 user
programs can run concurrently.
Computer com m unications
The PTC10 can receive text commands and send responses over USB, RS-232, Ethernet, and an
optional GPIB interface. All aspects of PTC10 operation can be controlled over these interfaces.
Eight digital I/O lines are also provided; these can interact with user programs to control most
aspects
Introduction 2
PTC10 Programmable Temperature Controller
on removable circuit boards. The chassis has
four wide and two narrow slots for these I/O cards. The wide slots (which are labeled 1 4 on the
back panel) can be occupied by optional temperature input and/or heater driver cards. The narrow
slots (slots 5 and 6) are occupied by general-purpose analog and digital I/O cards included as
standard equipment.
Replacing I/O cards
Cards can be added, removed, or rearranged by the user. No firmware setup is needed; the
system automatically recognizes the new cards. For most purposes, the six slots are identical and
cards do not need to be arranged in any particular order. However, the lower-numbered slots are
preferred for output cards because these slots get the most cooling from the fan. In addition, alarms
can only activate relays on a digital I/O card if the card is installed in slot 6.
Some channel-specific settings (PID feedback parameters, alarm settings, sensor type, custom
calibration data, and filter settings) may be lost when I/O cards are replaced or rearranged.
However, factory calibration is stored on the card and is not lost.
To add or replace an I/O card:
1. Unplug the PTC10 from the wall; otherwise, even if the instrument is switched off, live line
voltage could be present. Removing and installing I/O cards while the power is turned on
may permanently damage the instrument.
large Philips head screws on the
sides of the cover and lifting the cover straight up.
3. Remove the two flathead Phillips screws immediately t
back panel.
4. Remove the I/O card by pulling up alternately on the front and back of the card.
5. Install the new I/O card. Put the back of the card in place first, then press firmly down on
the front of the card. Ensure that the top of the card is level with the tops of all the other
cards.
6. Re-install the two back-panel screws and re-attach the top cover. The card can be damaged
if the screws are not installed.
7. Turn the PTC10 on. The new card should automatically appear on the Select screen, and
remote commands for the new card should automatically become available.
PTC320 thermistor/diode/RTD card
The PTC320 is a single-channel, multi-range input card that can read a variety of temperature
sensors. It can read resistances between 1 and 2.5 M , and can also read diode temperature
sensors.
Standard calibration curves are included for the following sensors.
the range of the standard calibration curve; outside this range, no reading appears for the sensor. It
may be possible to obtain a larger range by uploading a custom calibration curve.
Introduction 3
PTC10 Programmable Temperature Controller
Sensor
class
Manufacturer
Calibration
type
Range,
K
Diode
Scientific Instruments
Si410
1.0 450
Si430
1.0 400 Si440
1.0 500
LakeShore; Omega
DT-470 (=CY7)
1.4 475
DT-670 (=CY670)
1.4 500
Cryo-Con
S700
1.5 475
S800
1.4 385
S900
1.5 500
Ruthenium
oxide
LakeShore
RX-102A
0.050 40
RX-103A
1.2 40
RX-202A
0.050 40
Scientific Instruments
RO600
1.0 300
Cryo-Con
R400
2.0 273
R500
0.050 20
RTD
All
IEC751 (DIN43760)
48.15 1173.15
US
48.15 1173.15
Thermistor
Measurement
Specialties,
Inc.
(formerly YSI);
Omega
100
193.15 373.15
300
193.15 373.15
1000
193.15 373.15
2252
193.15 523.15
3000
193.15 523.15
5000
193.15 523.15
6000
193.15 523.15
10000 type B
193.15 523.15
10000 type H
193.15 523.15
30 k
233.15 523.15
100 k
233.15 423.15
300 k
298.15 423.15
1 M
298.15 423.15
Other resistive and diode sensors can be used with the PTC320, but require custom calibration
curves. For example, rhodium-iron, germanium, and carbon-glass sensors have too much sensorto-sensor variability to use a standard curve, and therefore must be custom-calibrated.
Connecting the sensor
The PTC320 has a 6-pin DIN socket that mates with standard 6-pin push-pull DIN plugs (i.e.
Digi-Key CP-1060-ND). This is the pinout of the socket, as it appears when looking at the back
panel:
1
5
4
2
6
3
Not connected
Excitation +Sense +
Ground
Excit
Introduction 4
PTC10 Programmable Temperature Controller
chassis.
The PTC320 passes an excitation current through the attached RTD, thermistor, or diode, and
senses the induced voltage. For the most accurate results all sensors should be read with a four-wire
configuration, using separate sense and excitation leads. However, for convenience the PTC320
can also read sensors attached with only two leads.
To make a two-wire measurement, connect one end of the sensor to pin 1 (Excitation ) and the
other to pin 5 (Excitation +). An inaccuracy is introduced because the resistance of the leads affects
the measurement; however, some thermistors have such a high resistance that the lead resistance
may be negligible in comparison.
A four-wire measurement eliminates the effect of lead resistance. In the four-wire configuration,
two of the wires carry the excitation current, while the other two wires sense the voltage that the
current produces across the sensor. RTDs sold with four wires normally have two wires of one
color, both attached to one side of the RTD, and two of a different color attached to the other side.
In this case, the RTD should be wired to the PTC320 in one of the following two ways (assuming
the leads are white and black):
Pin 1
Pin 2
Pin 3
Pin 4
Pin 5
Option 1
White
White
Unconnected
Black
Black
Option 2
Black
Black
Unconnected
White
White
RTDs with two wires can be modified by connecting two additional wires, one on each side of
the sensing element and as close to the sensing element as possible.
The higher the resistance of a sensor, the more its leads pick up noise from ambient
electromagnetic radiation. The noise level of high-resistance thermistors in particular can often be
improved by using a shielded cable and connecting the shield to pin 3.
Excitation current
The excitation current provided to the sensor is automatically determined by the PTC320. For
resistive sensors, the current is determined by the type of sensor and the measurement range as
shown in the table below. When a diode sensor is in use, the card always produces a 10 µA
excitation.
Measurem ent
range
RTD
excitation
Therm istor
excitation
Diode
excitation
30
5 mA
200 µA
100
2 mA
100 µA
300
1 mA
50 µA
1 k
500 µA
30 µA
3 k
200 µA
20 µA
10 k
100 µA
10 µA
30 k
50 µA
5 µA
100 k
10 µA
3 µA
300
5 µA
2 µA
2.5 V ( )
1 µA
1 µA
10 µA
Excitation current produced by the PTC320
The thermistor excitation current results in about 1 µW of power being dissipated in the
thermistor at the high end of each measurement range. Therefore, if the dissipation constant of the
thermistor is above 1 mW/°C, the measurement error due to self-heating should be less than 1
mK.
Introduction 5
PTC10 Programmable Temperature Controller
PTC321 RTD reader
Resistance temperature detectors (RTDs) use the resistance of a metal wire or film to indicate
temperature. RTDs are usually made of platinum which, being very non-reactive, produces sensors
with exceptional long-term stability. However, platinum RTDs are also expensive and have a
limited temperature range.
Typically, the resistance is measured by passing an excitation current through it and
measuring the resulting voltage drop. A four-wire RTD has two wires to carry the current and two
to measure the voltage. Negligible current flows through the voltage-measuring wires, ensuring
that the resistance of the wires does affect the measured voltage.
RTDs usually have the °C (IEC751
standard). The cient of 0.00392 °C is less common, even in America.
The PTC321 RTD reader reads up to four 100 ohm platinum RTDs with a 1 mA excitation
current. The current through the RTD can be reversed with each reading to null out parasitic
thermocouple voltages.
The PTC321 has a range of 10 , allowing it to read 100 European-type platinum RTDs
in the temperature range 215 to 850°C. RTDs with other base resistances can also be used, but
over a smaller temperature range.
The PTC321 is calibrated at ambient temperatures of 25 and 35°C. An on-board temperature
sensor continuously interpolates between these two calibrations to account for thermal drift of the
electronic components. Since the PTC10 enclosure is usually elevated 2 to 3 degrees above
ambient temperature, the accuracy of the PTC321 may be reduced if the ambient temperature rises
above about 32°C.
To further improve measurement stability, the PTC321 can control the main enclosure fan to
keep the card at a constant temperature (see the Channel.PCB button).
A narrow flange is available for the PTC321. With this flange mounted, the card can be plugged
into either slot 5 (normally occupied by the analog I/O card) or slot 6 (normally occupied by the
digital I/O card). Since all six slots of the PTC are identical except for their width, the I/O cards
can be arranged in any order as long as they fit into the slots. To order the narrow flange from SRS,
contact sales and ask for part number 7-01920-720.
Connecting the RTDs
RTDs are connected to the PTC321 with removable 5-pin, 3.5 mm terminal plugs (e.g.,
Weidmüller part number 169045). The supplied plugs use a tension clamp to hold the RTD wires.
To install the RTD wires:
1. Hold the plug such that the row of five small holes is on the right and the five larger holes are
on the left.
2. Each pair of holes is blocked by a metal clip. Place a small screwdriver into one of the small
holes and firmly push it into the narrow gap to the right of the clip. The screwdriver should
go in about half an inch and push the clip to the left.
3. The larger hole should open up. Place a stripped wire into the hole and remove the
screwdriver.
Plugs with screw clamps (e.g., nnect the
RTD wires to these plugs, but the wires often come loose, resulting in noisy temperature
measurements. The tension clamps are a little more difficult to install but produce a more reliable
connection.
Introduction 6
PTC10 Programmable Temperature Controller
On each connector, the top two pins receive the resistance signal, the middle pin is a ground that
can be connected to a shield or left unconnected, and the lower two pins provide the excitation
current.
Commercial 4-wire RTDs usually have two wires of the one color connected to one end of the
resistive sensor, and two of a different color connected to the other end. There is normally no
shield. In this case, the RTD plug should be wired in one of the following ways (assuming black and
white wires):
Pin 1
Pin 2
Pin 3
Pin 4
Pin 5
Option 1
White
Black
Unconnected
White
Black
Option 2
Black
White
Unconnected
Black
White
If the plug is wired any other way, no reading appears when the sensor is plugged into the RTD
reader.
RTDs with two wires must be modified by soldering two additional wires to the existing wires,
one on each side of the sensing element and as close to the sensing element as possible. The diagram
below shows how to connect the wires to the PTC321.
Connecting a 2-wire RTD to the PTC321 RTD reader
PTC323 2-channel thermistor/diode/RTD card
The PTC323 is a two-channel, multi-range input card that can read a variety of temperature
sensors. It can read resistances between 1 and 2.5 M , and can also read diode temperature
sensors.
Standard calibration curves are included for the follo
the range of the standard calibration curve; outside this range, no reading appears for the sensor. It
may be possible to obtain a larger range by uploading a custom calibration curve.
Connect the two wires that
came with the sensor (thin lines)
to the Signal inputs
Solder two additional wires (thick lines)
to the sensor and connect them
to the Excitation inputs
RTD
sensing
element
Signal
Signal
Ground
Excitation
Excitation
Introduction 7
PTC10 Programmable Temperature Controller
Sensor
class
Manufacturer
Calibration
type
Range,
K
Diode
Scientific Instruments
Si410
1.0 450
Si430
1.0 400 Si440
1.0 500
LakeShore; Omega
DT-470 (=CY7)
1.4 475
DT-670 (=CY670)
1.4 500
Cryo-Con
S700
1.5 475
S800
1.4 385
S900
1.5 500
Ruthenium
oxide
LakeShore
RX-102A
0.050 40
RX-103A
1.2 40
RX-202A
0.050 40
Scientific Instruments
RO600
1.0 300
Cryo-Con
R400
2.0 273
R500
0.050 20
RTD
All
IEC751 (DIN43760)
48.15 1173.15 US
48.15 1173.15
Thermistor
Measurement
Specialties,
Inc.
(formerly YSI);
Omega
100
193.15 373.15
300
193.15 373.15
1000
193.15 373.15
2252
193.15 523.15
3000
193.15 523.15
5000
193.15 523.15
6000
193.15 523.15
10000 type B (32.66 k at 0°C)
193.15 523.15
10000 type H (29.49 k at 0°C)
193.15 523.15
30 k
233.15 523.15
100 k
233.15 423.15
300 k
298.15 423.15
1 M
298.15 423.15
Other resistive and diode sensors can be used with the PTC320, but require custom calibration
curves. For example, rhodium-iron, germanium, and carbon-glass sensors have too much sensorto-sensor variability to use a standard curve, and therefore must be custom-calibrated.
Connecting the sensor
The sensors are connected via a 9-pin D-sub (DB9) socket that mates with any standard DB9
plug, such as Amphenol L717SDE09P with backshell 17E-1657-09. One plug and backshell is
provided with each PTC323. Here is a wiring diagram of the socket as it appears when looking at
the PTC10
Introduction 8
PTC10 Programmable Temperature Controller
A four-wire connection is used so that the PTC323 measures the resistance of the sensor and not
the wires going to the sensor. The +I and I pins provide a small current and should be connected
to the temperature sensor with two wires, preferably a shielded twisted pair. The +V and V pins
measure the voltage produced across the sensor and should be connected to +I and -I as close as
possible to the sensor.
Resistive sensors: Four-wire resistive sensors usually have two wires of one color attached to
one side of the RTD, and two of a second color attached to the other side. Two wires of the same
co
wires of the other color should be connected to the V and I pins.
Two-wire sensors can be converted to four-wire sensors by soldering two additional wires to the
existing leads, one on each side of the sensing element and as close to the sensing element as
possible. Soldering is essential; the wires should not be connected to the sensor by pressure alone
(e.g. crimping or clamping), as any resistance within the joint becomes part of the measured sensor
resistance.
The higher the resistance of an RTD or thermistor, the more sensitive it is to ambient
electromagnetic noise and the greater the need for shielded cables.
Diode sensors: Diode sensors can be connected in either direction. If no reading appears,
change the current direction from Forward to Reverse.
Diode sensors are especially susceptible to electromagnetic noise because the diode rectifies any
noise picked up by the sensor leads, increasing the measured voltage. It may be necessary to place
the sample within an electromagnetically shielded enclosure and to put EMI filters not only the on
the sensor leads but also on all other leads entering the enclosure. The filters should be located at
the point where the wires enter the enclosure, and the enclosure itself should be grounded. D-sub
and circular connectors with built-in filters, as well as individual filters, can be obtained from
Spectrum Advanced Specialty Products. We have found their 4000 pF pi filters to be effective.
These filters include capacitors to ground, which should be connected either to the ground pin (pin
3) of the sensor input connector or to chassis ground.
AD590 sensors: The PTC323 can read AD590 sensors if the sensor is connected in series with a
2 k resistor as shown below. Note that the diagram shows the sensor connected to channel A, but
it can also be connected to channel B. The diagram shows the back of the DB9 connector, that is,
the side that you solder to, with pin 1 in the bottom-right corner.
sistors
have a TCR of about 100 ppm/°C, which means that the sensor reading will drift upward by about
30 mK for each 1°C rise in ambient temperature. Thermal drift can be reduced substantially by
AD590
+I
1
6
5
9
+V
+
Introduction 9
PTC10 Programmable Temperature Controller
using a 5 ppm/°C resistor available from SRS; ask for part number 4-02502-457. For even better
stability, a 1 ppm/°C resistor such as the Riedon USR2G-2KX1, available from Digi-Key, can be
used. In any case, to minimize noise and drift, the resistor should be soldered directly to the pins on
the DB9 plug and covered up with the backshell.
Because AD590 sensors are highly sensitive to electromagnetic interference, the AD590 wires
and package must be shielded, with the shield connected to pin 3 of the DB9 connector.
Excitation current
The PTC323 measures the resistance of the sensor by passing an excitation current through it.
The larger the excitation, the less noise the temperature reading will have. However, if the
excitation is too large it will heat the sensor and cause higher than expected readings. Therefore,
e
Low power: minimizes sensor heating. This option is mainly for use with thermistors in
cryogenic applications. To compensate for the fact that heat conductivity decreases (and
thermistor resistance increases) as the temperature approaches absolute zero, the amount of
power that the sensor dissipates decreases as the measurement range is increased.
High power: minimizes noise. Power dissipation is kept roughly constant as the
measurement range is increased. This option is for use with RTDs or with any kind of sensor
at non-cryogenic temperatures.
Auto power: uses low power if the sensor type is set to thermistor or ROX, or high power
if the sensor type is set to RTD.
The PTC323 has 12 measurement ranges. Within any given range, it generates a constant
excitation current as shown in the table below. Note that the range has to be greater than the
sensor resistance, so if the sensor resistance is 10 k , for example, the range should be 30 k .
For diode sensors the range is always 2.5V and the excitation current is always 10 µA.
The graph below shows how the amount of power dissipated by the sensor depends on the range
and power settings. Sensor heating (degrees above the ambient temperature) is proportional to
power dissipation.
Left: the amount of current passed through the sensor by the PTC10; right:
the amount of power that the sensor dissipates due to that current
Introduction 10
PTC10 Programmable Temperature Controller
The table below shows some representative noise, electronic accuracy, and self-heating values for
free-standing sensors at room temperature. Note that the amount of self-heating can vary
dramatically depending on the thermal conductivity of whatever the sensor is attached to or
immersed in.
Noise
Accuracy
Self-heating
Low
power
High
power
Low
power
High
power
Low
power
High
Power
100 RTD
20 mK
0.8 mK
640 mK
40 mK
0.09 mK
100 mK
1 k thermistor
2 mK
0.08 mK
60 mK
3 mK
0.009 mK
40 mK
10 k thermistor
2 mK
0.02 mK
50 mK
2 mK
0.0009 mK
25 mK
100 k thermistor
9 mK
0.04 mK
220 mK
3 mK
0.00009 mK
2.5 mK
Noise, accuracy, and amount of self-
accuracy of the PTC10 immediately after calibration and does not account for self-heating or the accuracy
- above ambient temperature of a ~1 mm diameter sensor hanging
by its leads in still air (dissipation constant 1 mW/°C).
The graphs below show how electronic noise varies with temperature for several types of
sensors.
RMS noise levels for 100Ω and 1000Ω platinum RTD sensors as a function of temperature. At low power, the 100Ω
and 1000Ω sensors have about the same noise level.
Introduction 11
PTC10 Programmable Temperature Controller
RMS noise levels for 100Ω, 10kΩ, and 1MΩ (at 25°C) thermistors as a function of temperature
RMS noise for DT-670 diode sensor as a function of temperature.
The direction of the excitation current can be set by the user to forward, reverse, or AC
(switching between forward and reverse with each sample). AC current is recommended for
resistive sensors to reduce noise and drift. AC current cannot be used with diode sensors.
PTC330 thermocouple reader
How thermocouples work
If the two ends of a metal wire are held at different temperatures, the electrons at the hot end
move faster than those at the cold end. Since the electrons are free to diffuse throughout the wire,
they behave somewhat like a ga the hot end of the wire develops a
lower density of electrons relative to the cold end. As a result, the hot end has a slight positive
Introduction 12
PTC10 Programmable Temperature Controller
charge and the cold end a slight negative charge, producing a voltage difference. The exact voltage
depends on the temperature at each end and the composition of the wire.
A thermocouple has two wires that develop different voltages in response to a given temperature
difference. The wires are welded together at one end ) and the voltage difference
is measured at the other junction . If we know the cold junction temperature and if each
wire has a perfectly homogeneous composition, we can calculate the hot junction temperature.
Normally, we measure the cold junction temperature with another sensor such as an RTD or a
thermistor.
Thermocouple calibration tables generally assume that the cold junction is at 0 °C. Therefore, to
convert the thermocouple voltage to a temperature, to calculate what the
thermocouple voltage would be if the cold junction were at 0°C. For example, say a type K
thermocouple is used to measure the temperature of some liquid nitrogen. The thermocouple
reader measures a voltage of -6.829 mV and also determines that the cold junction is at 25°C. The
calibration table indicates that the voltage of a type K thermocouple at 25°C is 1.000 mV. So we
add 1 mV to the reading and look up the result, -5.829 mV, in the calibration table. The result is
the temperature of the inaccurately named -196°C.
Choosing a thermocouple
Thermocouples are inexpensive and can sense a wide range of temperatures, but without
frequent calibration they are accurate to no more than 1°C, partly because they tend to oxidize or
otherwise react with gases in their environment. Thermocouples made from thinner wires oxidize
more quickly and therefore exhibit more calibration drift than heavier-gauge thermocouples.
When selecting a thermocouple type, t s generally a tradeoff between sensitivity and
stability. That is, thermocouples that produce the largest voltages also have the most calibration
drift. With the excep he letters that describe thermocouples (E, J, K, etc.) appear
to be assigned in order of increasing long-term stability, with type C being the least stable and type
T the most. Therefore, if your application requires low noise, it might be best to choose type E; for
the best absolute accuracy, type T might be more appropriate.
Each PTC330 input supports one of the following thermocouple types:
Type E thermocouples have one chromel (90% nickel, 10% chromium) and one constantan
(60% copper, 40% nickel) wire. It has a large voltage change per degree (68 µV/°C), resulting in
excellent signal-to-noise ratio. However, its long-term stability is not very good. Type E
thermocouples are resistant to oxidation, but corrode if used in a vacuum or other reduced-oxygen
environment.
Type J thermocouples have one iron and one constantan wire. Above 500°C, oxidation of the
iron results in poor stability. This thermocouple is mainly used in legacy applications.
Type K thermocouples have one chromel and one alumel (95% nickel, 2% manganese, 2%
aluminum, 1% silicon) wire. With a wide temperatur s the most
popular type of thermocouple. Type K thermocouples are resistant to oxidation, but corrode if
used in a vacuum or other reduced-oxygen environment.
Type N thermocouples and 1% silicon) and one
and 0.1% magnesium) wire. They are designed for high stability,
especially at temperatures above 500°C. However, their sensitivity is low.
Type T thermocouples have one copper and one constantan wire. They are very accurate and
can be used in reducing atmospheres, but their temperature range is limited.
The following table summarizes some properties of thermocouples. Two temperature ranges are
given: the range that the thermocouple itself can withstand without losing its calibration, and the
built-in calibration tables, assuming that the cold junction
ng
Introduction 13
PTC10 Programmable Temperature Controller
appears on the display and any feedback loops for which the thermocouple is an input do not
function.
-2 standard for thermocouple-to-thermocouple
material variation. Not all commercial thermocouples may follow this standard; for example,
Omega specifies an accuracy of 2.2°C for its type J and K thermocouples. Greater accuracy is
possible if your thermocouple is custom calibrated. The accuracy values in this table only apply to
the thermocouple itself and
Tem perature range, °C
Accuracy
Type
Thermocouple
PTC10, cold
junction at 25°C
Sensitivity,
µV/°C at 25°C
Standard
calibration,
°C, at 0°C
Custom
calibration,
°C, <300°C
E
200 to 870
245 to 1025
60.9
1.7
1
J
0 to 760
185 to 1225
51.7
1.5
0.1
K
200 to1260
245 to 1395
40.6
1.5
0.1
N
270 to 1300
245 to 1325
26.5
1.5
T
200 to 350
245 to 425
40.6
0.5
0.1
Connecting thermocouples to the PTC330
The PTC330 thermocouple reader is factory-configured to read one of the above thermocouple
types. The thermocouple must be equipped with a miniature jack such as Omega part number
SMPW-J-M for type J, SMPW-K-M for type K, etc. The jacks on the PTC330 are color coded
according to the American (ANSI) color coding scheme, i.e. type J jacks are black, type K jacks are
yellow, etc. The colors may not conform to the standard colors used in other countries.
The thermocouple jacks are connected with thermocouple extension wires to a cold junction
block inside the PTC10. The cold junction temperature is measured with a platinum RTD
temperature sensor. The cold junction temperature is recorded so that if unexpected drift or other
artifacts appear in the thermocouple readings, it can be determined whether the artifacts are due to
erratic behavior of the cold junction. If readings are displayed in sensor units (see the
System.Other.Units button), the raw thermocouple EMFs are displayed in millivolts, not corrected
for the cold junction temperature, and the cold junction temperature is displayed in ohms.
inputs are optically isolated and the thermocouples can come in direct contact
with electrically live metal. In this case, however, the noise level and accuracy of the measurement
may be affected.
The PTC330 hardware is calibrated at ambient temperatures of 25 and 35°C. An on-board
temperature sensor continuously interpolates between these two calibrations to account for
is usually elevated 2
to 3 degrees above ambient temperature, the accuracy of the PTC330 may be compromised if the
ambient temperature rises above about 32°C.
To further improve measurement stability, the PTC330 can control the main enclosure fan to
keep the card at a constant temperature (see the manual entry for the Channel.PCB control).
PTC420 AC output card
The PTC420 AC output card has a solid-state relay that delivers mains current to the heater. It is
intended for control of large heaters including heating mantles, heating tape, and heating blankets.
The relay is either on or off; when on, the full AC mains voltage appears on the output. To vary the
output power, the PTC420 switches the relay on and then off once every 10 seconds (by default)
with a variable duty cycle.
Introduction 14
PTC10 Programmable Temperature Controller
The card can deliver at most 5 A of current. If the resistance of the heater is too small, the card
delivers more than its rated current and may be shut down by its internal protection circuitry. In
some cases the card may be damaged. The minimum permissible heater resistance depends on the
AC line voltage as shown in the table below. The table also shows the maximum power that the
card can deliver.
Line
voltage,
V
Exam ple
locations
Min heater
resistance,
ohm s
Max power at
min heater
resistance, W
Max power
at heater
resistance R, W
100
Japan
20
500
10000 / R
120
Canada, US
24
600
14400 / R
220
Russia
44
1100
48400 / R
230
Europe
46
1150
52900 / R
240
China, Australia
48
1200
57600 / R
The total AC current delivered at any one time by the all the PTC420 cards in a single chassis
cannot exceed 10 A
PTC430 50 W DC output card
The PTC430 DC output card can deliver up to 50 W of power and is intended for precise
control of small heaters. The card offers two voltage ranges (50 V and 20 V) and three current
ranges (1A, 0.5A, and 0.1A). An auto-range feature continuously adjusts the current and voltage
ranges to the smallest values needed to achieve the power specified with the channel Hi Lmt
setting.
The depends on the resistance of the heater; see the table
below.
Heater resistance
(R),
Optimum
output
range
Maximum
power, W
> 500
50 V 0.1 A
2500/R
500
50 V 0.1 A
5
100 500
50 V 0.5 A
2500/R
100
50 V 0.5 A
25
50 100
50 V 1 A
2500/R
50
50 V 1 A
50
20 50
50 V 1 A
R
20
20 V 2 A
20
10 20
20 V 2 A
400/R
10
20 V 2 A
40
< 10
20 V 2 A
4R
Maximum output power and optimum output range as a function of
heater resistance
, the heater must have a resistance of 50 ohms. If the
produces about 265W at 115V or 1060W
at 230V.
If the heatsink temperature of a DC output card exceeds 60
circuitry shuts down the output. This is likely to occur if one of the 50V output ranges is used when
the heater resistance is under 20 ; if the ambient temperature outside the chassis is above 30°C; if
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