Specifications

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 stability¹¹
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
Diode 340/3462	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 mA¹⁴	1 mΩ	1 mΩ	±0.002 Ω ±0.01% of rdg	2 mΩ
	positive	0 Ω to 500 Ω	1 mA¹⁴	1 mΩ	1 mΩ	±0.002 Ω ±0.01% of rdg	2 mΩ
	positive	0 Ω to 2500 Ω	0.1 mA¹⁴	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 µA¹⁴	100 µΩ	1 mΩ	±0.02% rng ±0.1% of rdg	2 mΩ
	negative	0 Ω to 30 Ω	30 µA¹⁴	100 µΩ	3 mΩ	±0.02% rng ±0.1% of rdg	6 mΩ
	negative	0 Ω to 100 Ω	10 µA¹⁴	1 mΩ	10 mΩ	±0.02% rng ±0.1% of rdg	20 mΩ
	negative	0 Ω to 300 Ω	3 µA¹⁴	1 mΩ	30 mΩ	±0.02% rng ±0.1% of rdg	60 mΩ
	negative	0 Ω to 1 k Ω	1 µA¹⁴	10 mΩ	0.1 Ω	±0.02% rng ±0.1% of rdg	0.2 Ω
	negative	0 Ω to 3 k Ω	300 nA¹⁴	10 mΩ	0.3 Ω	±0.02% rng ±0.1% of rdg	0.6 Ω
	negative	0 Ω to 10 k Ω	100 nA¹⁴	0.1 Ω	1 Ω	±0.02% rng ±0.1% of rdg	2 Ω
	negative	0 Ω to 30 k Ω	30 nA¹⁴	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 µA¹⁴	100 µΩ	300 µΩ	±0.02% rng ±0.05% of rdg	600 µΩ
	negative	0 Ω to 100 Ω	100 µA¹⁴	1 mΩ	1 mΩ	±0.02% rng ±0.05% of rdg	2 mΩ
	negative	0 Ω to 300 Ω	30 µA¹⁴	1 mΩ	3 mΩ	±0.02% rng ±0.05% of rdg	6 mΩ
	negative	0 Ω to 1 kΩ	10 µA¹⁴	10 mΩ	10 mΩ	±0.02% rng ±0.05% of rdg	20 mΩ
	negative	0 Ω to 3 kΩ	3 µA¹⁴	10 mΩ	30 mΩ	±0.02% rng ±0.05% of rdg	60 mΩ
	negative	0 Ω to 10 kΩ	1 µA¹⁴	0.1 Ω	0.1 Ω	±0.02% rng ±0.05% of rdg	0.2 Ω
	negative	0 Ω to 30 kΩ	300 nA¹⁴	0.1 Ω	0.3 Ω	±0.02% rng ±0.05% of rdg	0.6 Ω
	negative	0 Ω to 100 kΩ	100 nA¹⁴	1 Ω	3 Ω	±0.02% rng ±0.05% of rdg	6 Ω
	negative	0 Ω to 300 kΩ	30 nA¹⁴	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 rdg¹⁵	0.4 µV
Thermocouple 3464	positive	±50 mV	NA	0.1 µV	0.4 µV	±1 µV ±0.05% of rdg¹⁵	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
Capacitance 3465	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
Diode 3468	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	24-bit analog-to-digital
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 200-point CalCurves™, or user curves
SoftCal™	Improves accuracy of DT-470 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	Closed-loop 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 short-circuit protection

Heater output

	Loop 1	Loop 2
Heater output type	Variable DC current source	Variable DC voltage
Heater output D/A resolution	18-bit	14-bit
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
Heater resistance	Heater range	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	4-lead differential	2-lead, room temperature compensated	4-lead
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, Carbon-Glass, Cernox™, and Rox™	Most thermocouple types	CS-501GR
Standard curves	DT-470, DT-500D, DT-670, PT-100, PT-1000, RX-102A, RX-202A	Type E, Type K, Type T AuFe 0.07% vs. Cr, AuFe 0.03% vs Cr,	None
Input connector	6-pin DIN	Ceramic isothermal block	6-pin 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 current-bar 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 lock-out

Interfaces
IEEE-488.2 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	RS-232C
Max baud rate	19,200 baud
Connector	RJ-11
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 Non-latching, 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 (short-circuit 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 data-logging

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).