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The Model 340 has been discontinued. Please consider the Model 350 and the Model 336.

Model 340 Specifications

Input specifications

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 kΩ	1 µA¹⁴	10 mΩ	0.1 Ω	±0.02% rng ±0.1% of rdg	0.2 Ω
	negative	0 Ω to 3 kΩ	300 nA¹⁴	10 mΩ	0.3 Ω	±0.02% rng ±0.1% of rdg	0.6 Ω
	negative	0 Ω to 10 kΩ	100 nA¹⁴	0.1 Ω	1 Ω	±0.02% rng ±0.1% of rdg	2 Ω
	negative	0 Ω to 30 kΩ	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 pre-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/s on an input, 40 readings/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/min to 100 K/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 compliance	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.

Temperature controller heater power diagram

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, °C, 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/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/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/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/O	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) specified accuracy; 15 °C to 35 °C (59 °F to 95 °F) 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).

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The Model 340 has been discontinued. Please consider the Model 350 and the Model 336.

Model 340 Specifications

Input specifications

Thermometry

Control

Heater output

Loop 1 full scale heater power at typical resistance

Sensor input configuration

Front panel

Interfaces

IEEE-488.2 interface

Serial interface

Alarms

Relays

Analog voltage outputs

Digital I/O

Data card

General

3003 heater output conditioner

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