655T / 656T

Key Features:

• Selectable thermocouple input types offer flexibility to fit many applications.
• DIP switch-configuration and self-ranging technologies speed installation without pots, jumpers, or software.
• Linearizer function provides an output that is linear to the temperature or millivolt signal.
• Isolation eliminates ground loops, reduces noise, and blocks transient signals.
• Toggle-switch calibration simplifies field adjustments for faster and easier maintenance.
• Configuration lockout safety feature prevents tampering and accidental changes.
• Reverse-acting output capability enables inverse proportional control signals.
• Dual channel model saves space and reduces equipment costs.
• CJC control only requires a millivolt source to calibrate modules
• High-resolution sigma-delta A/D converters deliver superior accuracy for reliable measurements.
• Operating temperature range: -25 to 75°C (-13 to 167°F).

Product Details

General Input

Analog to Digital Converter (ADC)
16-bit S-D A/D converter.

Noise Rejection
Normal Mode: Better than 40dB @ 60Hz.
Common Mode: Better than 100dB @ 60Hz.

Input Overvoltage Protection
Bipolar Transient Voltage Suppressors (TVS).

Thermocouple Input

Thermocouple Linearization
On/off selectable.

Thermocouple Break Detection
TC sensor failure can be configured for either upscale or downscale.

Cold Junction Compensation (CJC) Control
On/off selectable.

Millivolt Input

Input Range
Ranges: ±15.6, ±31.3, ±62.5mV
0 to 0.125, 0.25, 0.5, 1.0V DC
Span adjust: 10 to 100% of range.
Zero adjust: 0 to 90% of range.


Output Range
Range: 4 to 20mA DC, 3.8 to 22mA range typical.

Output Compliance
Rload = (Vsupply – 12V) / 0.02A

Output Response Control
Proportional/inverse selectable.

Ambient Temperature Effect
Better than ±0.006% of input span per °C or ±100ppm/°C, whichever is greater.

Output Response Time (for input step change)
700mS typical to 98% of final output value.


Ambient Temperature
Operating: -25 to 75°C (-13 to 167°F).
Storage: -40 to 85°C (-40 to 185°F).

Relative Humidity
5 to 95%, noncondensing.

Power Requirement
12 to 50V DC @ 25mA for each output channel.

Inputs, outputs, and individual channels are isolated from each other for common-mode voltages up to 250V AC, or 354V DC off ground, on a continuous basis (will withstand 1500V AC dielectric strength test for one minute without breakdown).

Radiated Field Immunity (RFI)
Complies with EN61000-4-3 Level 3 and EN50082-1.

Electromagnetic Field Immunity (EMI)
Less than ±0.25% of output span effect.

Electrical Fast Transient (EFT)
Complies with EN61000-4-4 Level 3 and EN50082-1.

Electrostatic Discharge (ESD)
Complies with EN61000-4-2 Level 3 and EN50082-1.

Radiated Emissions
Meets or exceeds EN50081-1 for Class B equipment.

CE marked, UL & cUL listed.
Hazardous Locations: Class I: Div. 2; Groups A, B, C, D.


Case: Self-extinguishing NYLON type 6.6 polyamide thermoplastic UL94 V-2 NEMA Type 1 enclosure.

Connectors (Removable Terminal Blocks)
Wire Range: AWG #12-24.

Printed Circuit Boards
Military grade FR-4 epoxy glass circuit board.