The 370 has been discontinued. Please consider the Model 372.

Model 370 Specifications

Measurement typeAC, 4-lead differential, resistance
Number of inputs1; up to 16 with scanner
Measurement unitsΩ, K (with temperature response curve)
Resistance ranges2 mΩ to 2 MΩ (excitation dependent)
Reading rate10 readings per s (same range and channel)
Range change settling3 s + filter settling
Channel change (scan) settling3 s + filter settling
A/D resolution24-bit
Input noise figure (370/3716) 33 nV/vHz
Input noise figure (3708)2 nV/vHz
Measurement resolutionRange dependent, (see 370 performance specification table)
AccuracyRange dependent, (see 370 performance specification table)
Measurement temp coefficient(±0.0015% of reading ±0.0002% of range)/°C
Lead connectionsV+, V-, l+, l-, V shield, l shield, individual guards
Scanner lead connectionsV+, V-, l+, l- for each sensor, shield common to all
Max lead resistance100 Ω + 10% of resistance range per lead for current = 3.16 mA, 10 Ω + 10% of resistance range per lead for current = 10 mA
Input isolationMeasurement optically isolated from chassis ground
Common mode reductionMatched impedance voltage input and current output, active CMR
Excitation typeSinusoidal AC current source
Excitation frequency13.7 Hz (9.8 Hz and 16.2 Hz alternates)
Excitation currents21 ranges from 3.16 pA to 31.6 mA RMS
Minimum excitation power10-18 W into 100 kΩ (see 370 performance specification table)
Max DC current4 pA + 1% of excitation current (1.6 × 10-18 W into 100 kΩ)
Current protectionCurrent leads relay shorted on power-up and range change
Voltage ranges12 ranges from 2 µV to 632 mV RMS
Voltage over range20% nominal
Input impedanceApproaches 5 × 1012 Ω
Range selection modesManual, Voltage Excitation, Current Excitation, and Autorange
Scanner modesManual or Autoscan
FilterSettling times 1 s to 200 s
Additional software featuresMax/Min capture, Linear equation, user programmable pause on range and input change

Temperature conversion

Supported cryogenic temperature sensorsAny resistive sensor including NTC resistors (e.g., germanium, carbon-glass, Cernox™, ruthenium oxide [Rox™]) and PTC resistors (e.g., rhodium-iron RTD)
RequirementsRequires calibrated sensor and a temperature response curve loaded into the instrument at Lake Shore or by the user
Temperature coefficientNegative or positive
Temperature unitsK
Low temperatureBelow 20 mK in a well-designed system
Temperature resolutionSensor and temperature dependent (see sensor performance)
Curve memorySpace for twenty 200-point curves
Curve entryEntered via front panel, computer interface, or CalCurve™ option
Curve formatΩ/K, Log Ω/K

Temperature control

Control typeHigh resolution digital PID
Control modesClosed Loop PID, Open Loop
Tuning modesManual PID, Zones
Setpoint unitsΩ or K (with temperature calibration curve)
Setpoint resolutionSame as reading display resolution
Control stabilityBelow 10 mK p-p at 50 mK, system dependent
Heater output typeVariable DC current source
Heater output isolationOptically isolated from chassis and measurement ground
Output D/A resolution18-bit
Heater output ranges100 mA, 31.6 mA, 10 mA, 3.16 µA, 1 µA, 316 µA, 100 µA , 31.6 µA
Heater output compliance10 V
Max power of output ranges1 W, 100 mW, 10 mW, 1 mW, 100 µW, 10 µW, 1 µW, 0.1 µW (nominal 100 Ω)
Heater typeResistive
Heater resistance range1 Ω to 100 kΩ, 100 Ω for maximum power
Heater output gain accuracy±1% of setting
Heater output offset (at 0%)±0.02% of range
Max heater noise current<0.005% of range
PID Control Parameters
Proportional0.001 to 1000
Integral0 s to 10,000 s
Derivative0 s to 10,000 s
Manual Output0% to 100% (resolution 0.001%)
PID zone settings10 zones that include setpoint, heater range, PID, relays, and analog outputs (still)
Still outputUp to 1 W of power available using analog output 2
Heater protectionShort circuit-protected, disabled with a relay on power-up, defaults to off range on power-up, selectable heater range limit, open circuit detection
Scanner supportControl with scanned input is supported with reduced stability

Front panel

Display typeGraphic (8 line by 40 character) vacuum fluorescent display
Number of reading displays1 to 8
Reading display unitsmΩ, Ω, kΩ, MΩ, mK, K
Display resolution4, 5, or 6 digit, user selected
Display update rate2 readings per second
Reading display optionsΩ, K, Max, Min, Linear
Other displaysChannel number, units, resistance range, excitation voltage or current, excitation power, control setpoint, heater range, and heater output
Display annunciatorsReading errors, CMR, Alarm, Ramp, Zone, Remote
LED annunciatorsAutorange, Excitation Mode, Autoscan
Keypad36 key, numeric and specific functions

Interface

IEEE-488.2 interface capabilitySH1, AH1, T5, L4, SR1, RL1, PP0, DC1, DT0, C0, E1
Software supportLabVIEW™ driver for IEEE-488 interface (consult Lake Shore for availability)
Serial interface capabilityRS-232C, DE-9 connector, 9600 baud
Alarms
NumberUp to 32, high and low for each channel
SettingsSource, High Setpoint, Low Setpoint, Deadband, Latching/Non-latching,
Audible on/off
ActuatorsDisplay annunciator, beeper, relays
Relays
Number2
ContactsNormally Open, Normally Closed, and Common
Contact rating30 VDC at 5 A
OperationRelays may be activated on high/low alarm setpoints or manually
ConnectorDetachable terminal block
Analog voltage outputs
Number2
TypeVariable DC voltage source
ScaleUser specified
Range±10 V
Resolution0.3 mV, 0.003% of full scale
Accuracy±2.5 mV
Maximum current100 mA
Maximum power1 W
Minimum load resistance100 Ω (short circuit-protected)
Ground referenceChassis
OperationTracks reading, error (DR) using linear equation, or use as still heater
ConnectorBNC
Monitor output
OperationUser selects one of several analog voltage diagnostic points (must remain isolated)
ConnectorBNC
Frequency reference
Signal typePhase sensitive detector reference (must remain isolated)
Amplitude0 to +5 V nominal
WaveformSquare wave
ConnectorBNC

General

Ambient temperature15 °C to 35 °C at rated accuracy; 5 °C to 40 °C at reduced accuracy
Calibration schedule1 year
Power requirement100, 120, 220, 240 VAC, +6% -10%, 50 or 60 Hz, 50 VA
Size435 mm W × 89 mm H × 368 mm D (17 in × 3.5 in × 14.5 in), full rack
Weight5.9 kg (12.9 lb)
ApprovalCE mark

3716 and 3708 scanners

Size135 mm W × 66 mm H × 157 mm D (5.2 in × 2.6 in × 6.2 in)
Weight1 kg (2.1 lb)

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