Model 346 specifications

Sensor input configuration

Sensor inputs are electrically isolated from other circuits, but not each other

 Base configuration (10 sensors)Option cards (maximum of 4 installed)
 Inputs A and B Inputs C1 – C4, D1 – D43401 RTD/diode option card3402 thermocouple option card
Number of sensors2842
Supported sensorsResistive temperature devices (RTDs) up to 100 kΩ
Diodes up to 2.5 V		Thermocouple
Measurement configurationDedicated — one excitation and measurement circuit per inputRapidly scanned — one excitation and measurement circuit for each group of 4 inputs. Each active sensor is excited and updated in turn.Two dedicated inputs
Update rate100 ms100 ms dwell time per scanned active sensor. Disabled sensor inputs skipped. Update rate will vary from 100 ms for a single active sensor per group to 400 ms when all sensors in a group are active.100 ms
Measurement modes4-lead differential (I+, V+, I-, V-)
2-lead differential (I/V+, I/V-) with lead resistance compensation (future feature)		2-lead differential (V+, V-), room temperature compensated
Input connectorNormal density, socketed DE-9 D-subminiature (2 sensors per connector)Screw terminals in a ceramic isothermal block

Thermometry

 RTD (resistive)DiodeThermocouple
ExcitationConstant current with current reversal for EMF removalConstant currentN/A — thermocouples generate voltage without current excitation
Current ranges7 ranges between 100 nA and 1 mA10 µAN/A — Excitation current is not delivered by the instrument
Supported sensor examplesCernox®, Rox™, and 100 Ω platinum sensorsDT-670 silicon diodesMost thermocouple types, such as Type E and Type K
Pre-installed standard curvesPlatinum: PT-100
Rox: RX-102A
Rox: RX-103A
Rox: RX-202A		Diode: DT-670Type E
Type K

User curves: Space for up to 40 additional user curves (200-point maximum)

Math: Maximum and minimum, Setpoint stabilization indicator (future)

Filter: Averages 2 to 64 input readings

Additional features: 4-lead break detection with 2-lead failover mode (future), out-of-curve extrapolation (future), boosted resolution mode (future), and sensor redundancy support (future).

Input specifications

Standard measurement inputs and scanner option (Model 3401)

 Sensor temperature coefficientInput rangeExcitation current Display resolutionMeasurement resolutionElectronic accuracy (at 25 °C)1,2Measurement temperature coefficientElectronic control stability3
DiodeNegative 0 V to 2.5 V10 µA ±0.05%410 µV10 µV±80 µV ±0.005% of rdg(10 µV + 0.0015% of rdg)/°C±20 µV
PTC RTDPositive0 Ω to 10 Ω1 mA50.1 mΩ0.2 mΩ±0.002 Ω ±0.01% of rdg(0.01 mΩ + 0.001% of rdg)/°C±0.4 mΩ
0 Ω to 100 Ω1 mA51 mΩ2 mΩ±0.004 Ω ±0.01% of rdg(0.1 mΩ + 0.001% of rdg)/°C±4 mΩ
0 Ω to 1 kΩ1 mA510 mΩ
20 mΩ±0.04 Ω ±0.02% of rdg(1 mΩ + 0.001% of rdg)/°C±40 mΩ
NTC RTD
10 mV		Negative0 Ω to 100 Ω100 µA51 mΩ1.5 mΩ±0.01 Ω ±0.04% of rdg(0.1 mΩ + 0.001% of rdg)/°C±3 mΩ
0 Ω to 300 Ω30 µA51 mΩ4.5 mΩ±0.01 Ω ±0.04% of rdg(0.3 mΩ + 0.0015% of rdg)/°C±9 mΩ
0 Ω to 1 kΩ10 µA510 mΩ15 mΩ + 0.002% of rdg±0.1 Ω ±0.04% of rdg(1 mΩ + 0.001% of rdg)/°C±30 mΩ ±0.004% of rdg
0 Ω to 3 kΩ3 µA510 mΩ45 mΩ + 0.002% of rdg±0.1 Ω ±0.04% of rdg(3 mΩ + 0.0015% of rdg)/°C±90 mΩ ±0.004% of rdg
0 Ω to 10 kΩ1 µA5100 mΩ150 mΩ + 0.002% of rdg±1.0 Ω ±0.04% of rdg(10 mΩ + 0.001% of rdg)/°C±300 mΩ ±0.004% of rdg
0 Ω to 30 kΩ300 nA5100 mΩ450 mΩ + 0.002% of rdg±2.0 Ω ±0.04% of rdg(30 mΩ + 0.001% of rdg)/°C±900 mΩ ±0.004% of rdg
0 Ω to 100 kΩ100 nA51 Ω1.5 Ω + 0.005% of rdg±10.0 Ω ±0.04% of rdg(100 mΩ + 0.002% of rdg)/°C±3 Ω ±0.01% of rdg

1 With current reversal enabled, for RTD measurements
2 All input accuracy specifications have a minimum confidence interval of 95% with a test uncertainty ratio of 4:1
3 Control stability of the electronics only, in ideal thermal system
4 Current source error has negligible effect on measurement accuracy
5 Current source error is removed during calibration

Output electrical characteristics

 Outputs 1 – 4Outputs 5 – 8
Number of outputs44
FunctionPrimary heatersAuxiliary low-power heaters
Analog-out temperature reference
Output typeVariable DC unipolar current sourceVariable DC unipolar voltage source
RangesTwo: 200 mA and 2 AOne: 10 V
Compliance650 V100 mA
Maximum power100 W (into 25 Ω load)1 W (into 100 Ω load)
Heater load range10 to 100 Ω≥100 Ω
ConnectorNormal density socketed DA-15, D-subminiature10-pin 2.5 mm detachable terminal block
GroundingOutput referenced to chassis ground
Safety limitsCurve temperature, power up heater off, short and open circuit protection

6 Maximum level possible before the output will no longer be able to supply the requested output and power output will be less than communicated by the instrument

Heater groups

Multiple physical outputs can be logically combined to act like a single virtual output. This allows more than 100 W to be safely supplied to a single location, with the use of two or more 100 W heaters.

Number of groups: 2 (output groups 9 and 10)

Groupable outputs: Outputs 1 to 4

Number of outputs per group: 2, 3, or 4

Analog output temperature reference

Produce a 0 V to 10 V reference based on a defined sensor reading. The temperature value corresponding to 0 V and 10 V can be configured by the user to optimize for resolution or temperature range.

Availability: Outputs 5 to 8

Output range: 0 to 10 VDC

Accuracy: ±2.5 mV

Resolution: 0.3 mV

Data source: Temperature or sensor units

Scaling: Linear, range settable

Output temperature control characteristics

Available control modes

 DescriptionAvailability
Open loopFixed heater output; input temperature used only for temperature limit protectionAll outputs
Closed-loop PIDHeater output changes dynamically to maintain the temperature of an input using PID controlAll outputs
ZonesClosed-loop PID control with predefined settings for different temperature zonesOutputs 1 to 4, output groups 9 to 10
Warm-upCoordinated control of multiple outputs to bring the whole system to room temperatureOutputs 1 to 4, output groups 9 to 10

Closed-loop update rate: 10/s

Closed-loop setpoint ramping: 0.1 K/min to 100 K/min

Zone control: 10 temperature zones with P, I, D, manual out, range, control input, ramp rate

Interface

USB host (front panel)

Type: USB 3.0, mass storage class (MSC) device

Function: Firmware updates, diagnostic logs

Connector: USB Type-C™

USB device (rear panel)

Type: USB 2.0

Function: Command and control, emulates a standard RS-232 serial port

Baud rate: 921,600

Connector: B-type USB connector

Ethernet

Function: TCP/IP command and control

Communications protocol: IPv4 and IPv6

Connector: RJ-45 Gigabit Ethernet

Optional IEEE-488.2

Capabilities: SH1, AH1, T5, L4, SR1, RL1, PP0, DC1, DT0, C0, E1

Reading rate: To 10 rdg/s on each input

 

Software support: ColdSync™, MeasureLINK™, LabVIEW™, Python™

 

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, low, or both alarms for any input, or manual mode

Connector: 10-pin 2.5 mm detachable terminal block

Digital inputs

Number of inputs: 2

Isolation: Optical

Maximum low-level input voltage: +1 V

Minimum high-level input voltage: +4 V

Safe input voltage range: -5 V to +35 V

Operation: Reset min/max, All off (pending)

User-exposed +5 V supply range: Typical 5 V ±10% up to 100 mA continuous

AUX 24 VDC input

Function: Provide auxiliary power to possible future option cards that may require it

Isolation: Isolated from all other internal instrument power supplies

Operating range: 24 VDC nominal, 22 VDC minimum, 26 VDC maximum

Maximum allowed current draw: 2.5 A

Protections: Over current, over voltage, under voltage, inverted polarity

Front panel

Display: 5 in capacitive touch, color TFT-LCD WVGA (800 × 480) with LED backlight

Power switch: SPST mains/line power switch

General

Ambient temperature: 15 °C to 35 °C at rated accuracy; 5 °C to 40 °C at reduced accuracy

Instrument max field exposure: 5 mT (50 G) DC

Power requirement: 100 to 240 VAC (universal input), 50/60 Hz, 520 VA maximum

Size: 435 mm W × 89 mm H × 368 mm D (17 in × 3.5 in × 14.5 in), full rack

Weight: 6.1 kg (13.4 lb)

Approval: CE, CSA, NRTL mark (contact Lake Shore for availability)

Altitude: <2000 m