

Input specifications  click here for sample calculations of typical sensor performance 


Sensor temperature coefficient 
Input range 
Excitation current 
Display resolution 
Measurement resolution 
Electronic accuracy offset 
Electronic control stability^{11} 
Diode 340/3462 
negative 
0 V to 2.5 V 
10 µA
± 0.05%^{12, 13} 
10 µV 
10 µV 
±80 µV ±0.005% of rdg 
20 µV 
negative 
0 V to 7.5 V 
10 µA
± 0.05%^{12, 13} 
10 µV 
10 µV 
±80 µV ±0.01% of rdg 
20 µV 
PRC RTD 340/3462 
positive 
0 Ω to 250 Ω 
1 mA^{14} 
1 mΩ 
1 mΩ 
±0.002 Ω ±0.01% of rdg 
2 mΩ 
positive 
0 Ω to 500 Ω 
1 mA^{14} 
1 mΩ 
1 mΩ 
±0.002 Ω ±0.01% of rdg 
2 mΩ 
positive 
0 Ω to 2500 Ω 
0.1 mA^{14} 
10 mΩ 
10 mΩ 
±0.03 Ω ±0.02% of rdg 
20 mΩ 
NTC RTD 1 mV 340/3462 
negative 
0 Ω to 10 Ω 
100 µA^{14} 
100 µΩ 
1 mΩ 
±0.02% rng ±0.1% of rdg 
2 mΩ 
negative 
0 Ω to 30 Ω 
30 µA^{14} 
100 µΩ 
3 mΩ 
±0.02% rng ±0.1% of rdg 
6 mΩ 
negative 
0 Ω to 100 Ω 
10 µA^{14} 
1 mΩ 
10 mΩ 
±0.02% rng ±0.1% of rdg 
20 mΩ 
negative 
0 Ω to 300 Ω 
3 µA^{14} 
1 mΩ 
30 mΩ 
±0.02% rng ±0.1% of rdg 
60 mΩ 
negative 
0 Ω to 1 k Ω 
1 µA^{14} 
10 mΩ 
0.1 Ω 
±0.02% rng ±0.1% of rdg 
0.2 Ω 
negative 
0 Ω to 3 k Ω 
300 nA^{14} 
10 mΩ 
0.3 Ω 
±0.02% rng ±0.1% of rdg 
0.6 Ω 
negative 
0 Ω to 10 k Ω 
100 nA^{14} 
0.1 Ω 
1 Ω 
±0.02% rng ±0.1% of rdg 
2 Ω 
negative 
0 Ω to 30 k Ω 
30 nA^{14} 
0.1 Ω 
3 Ω 
±0.02% rng ±0.1% of rdg 
6 Ω 
NTC RTD 10 mV 340/3462 
negative 
0 Ω to 30 Ω 
300 µA^{14} 
100 µΩ 
300 µΩ 
±0.02% rng ±0.05% of rdg 
600 µΩ 
negative 
0 Ω to 100 Ω 
100 µA^{14} 
1 mΩ 
1 mΩ 
±0.02% rng ±0.05% of rdg 
2 mΩ 
negative 
0 Ω to 300 Ω 
30 µA^{14} 
1 mΩ 
3 mΩ 
±0.02% rng ±0.05% of rdg 
6 mΩ 
negative 
0 Ω to 1 kΩ 
10 µA^{14} 
10 mΩ 
10 mΩ 
±0.02% rng ±0.05% of rdg 
20 mΩ 
negative 
0 Ω to 3 kΩ 
3 µA^{14} 
10 mΩ 
30 mΩ 
±0.02% rng ±0.05% of rdg 
60 mΩ 
negative 
0 Ω to 10 kΩ 
1 µA^{14} 
0.1 Ω 
0.1 Ω 
±0.02% rng ±0.05% of rdg 
0.2 Ω 
negative 
0 Ω to 30 kΩ 
300 nA^{14} 
0.1 Ω 
0.3 Ω 
±0.02% rng ±0.05% of rdg 
0.6 Ω 
negative 
0 Ω to 100 kΩ 
100 nA^{14} 
1 Ω 
3 Ω 
±0.02% rng ±0.05% of rdg 
6 Ω 
negative 
0 Ω to 300 kΩ 
30 nA^{14} 
1 Ω 
30 Ω 
±0.02% rng ±0.25% of rdg 
60 Ω 
Thermocouple 3464 
positive 
±25 mV 
NA 
0.1 µV 
0.2 µV 
±1 µV ±0.05% of rdg^{15} 
0.4 µV 
positive 
±50 mV 
NA 
0.1 µV 
0.4 µV 
±1 µV ±0.05% of rdg^{15} 
0.8 µV 
Capacitance 3465 
positive or negative 
0 nF to 150 nF 
4.88 kHz
1 V square wave 
10 pF 
2.0 pF 
±50 pF ±0.1% of rdg 
4.0 pF 
positive or negative 
0 nF to 15 nF 
4.88 kHz
1 V square wave 
1 pF 
0.2 pF 
±50 pF ±0.1% of rdg 
0.4 pF 
Diode 3468 
negative 
0 V to 2.5 V 
10 µA
± 0.05%^{12, 13} 
100 µV 
20 µV 
±160 µV ±0.01% of rdg 
40 µV 
negative 
0 V to 7.5 V 
10 µA
± 0.05%^{12, 13} 
100 µV 
20 µV 
±160 µV ±0.02% of rdg 
40 µV 
PTC RTD 3468 
positive 
0 Ω to 250 Ω 
1 mA ± 0.3%^{14} 
10 mΩ 
2 mΩ 
±0.004 Ω ±0.02% of rdg 
4 m Ω 
positive 
0 Ω to 500 Ω 
1 mA ± 0.3%^{14} 
10 mΩ 
2 mΩ 
±0.004 Ω ±0.02% of rdg 
4 m Ω 
positive 
0 Ω to 5000 Ω 
1 mA ± 0.3%^{14} 
100 mΩ 
20 mΩ 
±0.06 Ω ±0.04% of rdg 
40 m Ω 
NTC RTD 3468 
negative 
0 Ω to 7500 Ω 
10 µA ± 0.05%^{14} 
100 mΩ 
50 mΩ 
±0.01 Ω ±0.04% of rdg 
0.1 Ω 

^{11} Control stability of the electronics only, in an ideal thermal system ^{12} Current source error has negligible effect on measurement accuracy ^{13} Diode input excitation current can be set to 1 mA – refer to the Model 331 user manual for details ^{14} Current source error is removed during calibration ^{15} Accuracy specification does not include errors from room temperature compensation 


Thermometry 
Number of inputs 
2 included (additional inputs optional) 
Input configuration 
Each input is factory configured as diode/RTD. Thermocouple and capacitance are optional and sold as additional input cards. 
Isolation 
Sensor inputs optically isolated from other circuits but not from each other 
A/D resolution 
24bit analogtodigital 
Input accuracy 
Sensor dependent – refer to Input Specifications table 
Measurement resolution 
Sensor dependent – refer to Input Specifications table 
Maximum update rate 
Up to 20 readings per s on an input, 40 readings per s on all inputs 
Autorange 
Automatically selects appropriate NTC RTD range 
User curves 
Forty 200point CalCurves™, or user curves 
SoftCal™ 
Improves accuracy of DT470 diode or platinum RTD sensors 
Math 
Maximum and minimum of input readings and linear equation 
Filter 
Averages input readings to quiet display, settable time constant 

Control 

Control loops 
2 
Control type 
Closedloop digital PID with manual heater power output, or open loop 
Tuning 
Autotune (one loop at a time), manual PID, zones 
Control stability 
Sensor dependent – to 2× measurement resolution (in an ideal thermal system) 
PID control settings 
Proportional (gain) 
0 to 1000 with 0.1 setting resolution 
Integral (reset) 
1 to 1000 with 0.1 setting resolution 
Derivative (rate) 
1 to 1000 s with 1 s resolution 
Manual output 
0 to 100% with 0.01% setting resolution 
Zone control 
10 temperature zones with P, I, D, manual heater power out, and heater range 
Setpoint ramping 
0.1 K per min to 100 K per min 
Safety limits 
Setpoint limit, curve temp limits, heater output, slope limit, heater range limit, power up heater off, and shortcircuit protection 

Heater output 

Loop 1 
Loop 2 
Heater output type 
Variable DC current source 
Variable DC voltage 
Heater output D/A resolution 
18bit 
14bit 
Max heater power 
100 W 
1 W 
Max heater output current 
2 A 
0.1 A 
Heater output complaince 
50 V 
10 V 
Heater source impedance 
NA 
0.01 Ω 
Heater output ranges 
5 decade steps in power 
1 
Heater load type 
Resistive 
Resistive 
Heater load range 
10 Ω to 100 Ω recommended 
100 Ω minimum 
Heater load for max power 
25 Ω 
100 Ω 
Heater noise (<1 kHz) RMS 
50 µV + 0.001% of output voltage 
<0.3 mV 
Isolation 
Optical isolation between output and other circuits 
None 
Heater connector 
Dual banana 
BNC 


Loop 1 full scale heater power at typical resistance 
Heater resistance 
Heater range 
Maximum current 
2 A 
1 A 
0.5 A 
0.25 A 
10 Ω 
5 
40 W 
10 W 
2.5 W 
625 mW 
4 
4 W 
1 W 
250 mW 
62.5 mW 
3 
0.4 W 
100 mW 
25 mW 
6.25 mW 
2 
40 mW 
10 mW 
2.5 mW 
625 µW 
1 
4 mW 
1 mW 
250 µW 
62.5 µW 
25 Ω 
5 
100 W 
25 W 
6.25 W 
1.56 W 
4 
10 W 
2.5 W 
625 mW 
156 mW 
3 
1 W 
250 mW 
62.5 mW 
15.6 mW 
2 
100 mW 
25 mW 
6.25 mW 
1.56 mW 
1 
10 mW 
2.5 mW 
625 µW 
156 µW 
50 Ω 
5 
50 W 
50 W 
12.5 W 
3.12 W 
4 
20 W 
5 W 
1.25 W 
312 mW 
3 
2 W 
500 mW 
125 mW 
31.2 mW 
2 
200 mW 
50 mW 
12.5 mW 
3.12 mW 
1 
20 mW 
5 mW 
1.25 mW 
312 µW 


Extending temperature controller heater power It is often necessary to extend the heater power of a cryogenic temperature controller to conduct experiments above room temperature. This diagram illustrates a practical way to increase the control output of the Model 340 to several hundred watts. A programming resistor, R_{pgm}, is placed across the controller’s heater output current source. As the heater output current changes, a changing voltage is generated across R_{pgm}. That voltage is used to program a large external power supply. R_{pgm} should be chosen so that a low current range of the controller can be used. The control output of loop 2 on the Model 340 is a voltage, thus it can be connected directly to the external power supply without R_{pgm}. 





Sensor input configuration 


Diode/RTD 
Thermocouple 
Capacitance 
Measurement type 
4lead differential 
2lead, room temperature compensated 
4lead 
Excitation 
Constant current with current reversal for RTDs 
NA 
4.88 kHz, 1 V square wave 
Supported sensors 
Diodes: Silicon, GaAlAs RTDs: 100 Ω Platinum, 1000 Ω Platinum, Germanium, CarbonGlass, Cernox™, and Rox™ 
Most thermocouple types 
CS501GR 
Standard curves 
DT470, DT500D, DT670, PT100, PT1000, RX102A, RX202A 
Type E, Type K, Type T AuFe 0.07% vs. Cr, AuFe 0.03% vs Cr, 
None 
Input connector 
6pin DIN 
Ceramic isothermal block 
6pin DIN 


Front Panel


Display

Graphic LCD with fluorescent backlight 
No. of reading displays

1 to 8 
Display Units 
Temperature in K, ºC, or sensor units 
Temp display resolution

0.0001 K below 10 K, 0.001 K above 10 K 
Sensor units display resolution

Sensor dependent, to 6 digits 
Setpoint setting resolution

Same as display resolution (actual resolution in sensor dependent) 
Heater output display 
Numeric display in percent of full scale for power or currentbar graph display of heater output available 
Heater output resolution

0.1% numeric or 2% graphical 
Keypad

Numeric plus special function 
Front panel features 
Front panel curve entry, display brightness control, and keypad lockout 

Interfaces 

IEEE488.2 interface

Features 
SH1, AH1, T5, L4, SR1, RL1, PP0, DC1, DT0, C0, E1 
Reading rate 
To 20 readings per s 
Software Support 
National instruments LabVIEW™ driver 
Serial interface

Electrical format 
RS232C 
Max baud rate 
19,200 baud 
Connector 
RJ11 
Reading rate 
To 20 readings per s 
Alarms


Number 
Two, high and low, for each installed input 
Data source 
Temperature, Sensor Units, and Linear Equation 
Settings 
Source, High and Low Setpoint , Latching or Nonlatching, and Audible On/Off 
Actuators 
Display, annunciator, beeper, and relays 
Relays


Number 
2 
Contacts 
Normally open (NO), normally closed (NC), and common (C) 
Contact rating 
30 VDC at 2 A 
Operation 
Activate relays on high or low alarms for any input, or manual off/on 
Connector 
Detachable terminal block 
Analog voltage outputs (when not used as control loop 2 output) 
Number 
2 
Scale 
User selected 
Update rate 
20 readings per s 
Data source 
Temperature, Sensor Units, and Linear Equation 
Settings 
Input, Source, Top of Scale, Bottom of Scale, or Manual 
Range 
±10 V 
Resolution 
1.25 mV 
Accuracy 
±2.5 mV 
Max output power 
1 W 
Min load resistance 
100 Ω (shortcircuit protected) 
Source impedance 
0.01 Ω 
Digital I/Ω 
5 inputs and 5 outputs – TTL voltage level compatible 
Data card 
PC card Type II slot used for curve transfer, setup storage, and datalogging 

General 

Ambient temp range 
20 °C to 30 °C (68 °F to 86 °F) for specified accuracy; 15 °C to 35 °C (59 °F to 95 °F) for reduced accuracy 
Power requirements 
100, 120, 220, 240 VAC (+5%, 10%), 50 or 60 Hz; 190 VA 
Size 
432 mm W × 89 mm H × 368 mm D (17 in × 3.5 in × 14.5 in), full rack 
Weight 
8 kg (17.6 lb) approx. 
Approval 
CE mark 


3003 Heater output conditioner 

The heater output conditioner is a passive filter which further reduces the already low Model 340 heater output noise. The typical insertion loss for the Model 3003 is 20 dB at or above line frequency, and >40 dB at or above double line frequency. A 144 mm W × 72 mm H × 165 mm D (5.7 in × 2.8 in × 6.5 in) panel mount enclosure houses this option, and it weighs 1.6 kg (3.5 lb). 




