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Product short description:
  • DC current input
  • Single, dual, or quad I/O loop-powered isolators

These units receive 4-20mA process current inputs and provide isolated 4-20mA output signals. Power is derived from the input signal current. Each channel operates independently and is isolated from the others to prevent interaction between channels.

671T, 672T, 674T: Multi-Channel, Two-Wire Isolators Description

For easy troubleshooting, each unit has LEDs and diagnostic test points. Fault LEDs identify output open loop conditions and load compliance problems. The precision 10 ohm sense resistor enables monitoring of the output signal without disturbing field wiring.

Input / Output Ranges
4 to 20mA DC input.
4 to 20mA DC output.

Power Requirement: Loop-powered (power derived from input signal current).

Approvals
CE marked. UL, cUL listed.
Class I; Division 2; Groups A, B, C, D.

671T, 672T, 674T Performance

IMPORTANT: The 671T transmitter is an input loop powered current isolator. Its input voltage burden is normally a function of its output voltage drop and is computed as 4.9V+Iout*Rout. If the output load resistance Rout is excessive relative to the input loop voltage, or Rout is open-circuited, the input voltage burden may increase up to the limit of available input loop voltage. Consequently, if there are any loop-powered transmitters connected in series in the 671T input loop, this output loop fault can pinch-off excess input loop voltage, reducing the available voltage to power any series-connected transmitters in the loop, potentially causing them to lose regulation of the input loop current. You could select a different current isolator than 671T, or a different series transmitter that is separately powered to avoid this fault condition.

Reference Test Conditions: Input/Output current: 4 to 20mA; output load 250 ohms; 77°F (25°C).

Input: 4 to 20mA input (each channel).

Input Burden
The voltage drop is a function of the input current and load resistance and is calculated as follows:
Input Voltage Drop = 4.9V DC + (0.0212A x Rload).
 Example:  For Rload = 250 ohms, Vdrop = 10.2V DC.

Output: 4-20mA DC output (each channel).

Output Load: 0 to 525 ohms.

Accuracy: Better than ±0.1% of output span. Error includes the combined effects of isolator repeatability, hysteresis, terminal point linearity and adjustment resolution.

Calibration: One 15-turn potentiometer per channel, accessible from front of the unit.

Ambient Temperature Effect: Less than ±0.01% of output span per °F (±0.018% per °C) over the ambient temperature range for reference test conditions. This specification includes the combined effects of zero and span over temperature.

Output Ripple: Less than ±0.1% of the maximum output span.

Bandwidth: -3dB at 2.2Hz, typical.

Response Time: For a step input, the output reaches 98% of output span in less than 300mS, typical, into 250 ohms.

Noise Rejection: Common mode: 110dB at 60Hz, typical.

Diagnostics
LED fault indicator: Lights for output open loop detection or load compliance problem.
Field test points: An internal 10 ohm sense resistor provides test points for monitoring the output signal current during field maintenance with a voltmeter.

Environmental

Ambient Temperature
Operating: -25 to 70°C (-13 to 158°F).
Storage: -40 to 85°C (-40 to 185°F).

Relative Humidity: 5 to 95%.

Power Requirement
Power is derived from the input signal loop.
In the event of an open output circuit, the input loop voltage drop is limited below 20V, nominal.
Isolator has reverse polarity protection.

Isolation: 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): Designed to comply with EN61000-4-3 Level 3 (10V/m, 80 to 1000MHz AM and 900MHz keyed) and European Norm EN50082-1.

Electromagnetic Field Immunity (EMI): Less than ±0.25% of output span effect under the influence of electromagnetic fields from switching solenoids, commutator motors, and drill motors.

Electrical Fast Transient (EFT): Complies with EN61000-4-4 Level 3 (2KV) and European Norm EN50082-1.

Surge Immunity: Complies with EN61000-4-5 Level 3 (2KV) and European Norm EN50082-1.

Electrostatic Discharge (ESD): Complies with EN61000-4-2 Level 3 (8KV air, 4KV direct to the enclosure port) and European Norm EN50082-1.

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

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

Physical

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

Connectors (Removable Terminal Blocks): Wire Range: AWG #14-22 (AWG #12 stranded only).

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

Dimensions
1.05W x 4.68H x 4.35D inches.
26.7W x 118.9H x 110.5D millimeters.

Shipping Weight: 1 pound (0.45 Kg) packed.

  • Multiple channels on a single unit saves space and reduces costs.
  • Galvanic isolation eliminates ground loops, reduces noise, and blocks transient signals.
  • Independent channels prevent signal interaction and offer spares for later use.
  • Fault LEDs provide a clear visual warning of open or failed process loops.
  • Single calibration pot per channel enables one-step, precise calibration
  • Operating Temperature range 25 to 70°C (-13 to 158°F)
Why Do I Need Electrical Isolation? - 8500988 (Log in to view the file)
Why do we need signal isolation? Acromag is in the business of signal conditioning. We manufacture circuits that amplify, isolate, filter, and convert one signal form to another. Most of these circuits also provide electrical isolation. However, added isolation has a cost. Thus, sometimes customers either question their need for isolation or fail to recognize...
How to Select the Right Isolator - 8401045
The Ins and Outs of Isolation: A Guide to Selecting the Right Isolator Acromag manufactures a variety of isolators to provide a cost-effective solution for many applications. The primary function of the isolator is to eliminate ground loops that may exist between two or more instruments. A classical application isolates the control room equipment (computers,...
How to Choose a 4-20mA Isolator - 8400850
Very often, the simple task of choosing an isolator requires more than just comparing the number of channels and the cost per point. To help you with this exercise, here are some concepts to know when you need to choose a 4-20 mA isolator. The lowest cost approach is a two-wire system using output loop-powered...
How to Use Acromag 600T Series Isolated Transmitters - 8401028
Application 1 Re-transmitting a signal from a two-wire loop to a second location. Solution Use either a model 651T-0600 (single channel) or 652T-0600 (dual channel) transmitter. Application 2 Splitting a signal from a two-wire loop: two outputs for different locations. Solution Use either a 653T-0600 (single input, dual output) or 652T-0600 (dual input, dual output)...

Manuals

671T, 672T, 674T User Manual (Log in to download the file)

  • Compare

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    • 10W, 15W, 30W, 60W, 90W, 120W, and 240W models
    • Universal Input (85-264V AC / 100-370V DC)
    • Lightweight and compact size
     
    Select options

Additional information

Weight 8 oz
Dimensions 1.5 × 5 × 4.5 in
Part Number

671T-0600: Single I/O Channel, 672T-0600: Dual I/O Channel, 674T-0600: Quad I/O Channel

Product Series

600 Series

Power

Loop Power

  • Description

    671T, 672T, 674T: Multi-Channel, Two-Wire Isolators Description

    For easy troubleshooting, each unit has LEDs and diagnostic test points. Fault LEDs identify output open loop conditions and load compliance problems. The precision 10 ohm sense resistor enables monitoring of the output signal without disturbing field wiring.

    Input / Output Ranges
    4 to 20mA DC input.
    4 to 20mA DC output.

    Power Requirement: Loop-powered (power derived from input signal current).

    Approvals
    CE marked. UL, cUL listed.
    Class I; Division 2; Groups A, B, C, D.

    671T, 672T, 674T Performance

    IMPORTANT: The 671T transmitter is an input loop powered current isolator. Its input voltage burden is normally a function of its output voltage drop and is computed as 4.9V+Iout*Rout. If the output load resistance Rout is excessive relative to the input loop voltage, or Rout is open-circuited, the input voltage burden may increase up to the limit of available input loop voltage. Consequently, if there are any loop-powered transmitters connected in series in the 671T input loop, this output loop fault can pinch-off excess input loop voltage, reducing the available voltage to power any series-connected transmitters in the loop, potentially causing them to lose regulation of the input loop current. You could select a different current isolator than 671T, or a different series transmitter that is separately powered to avoid this fault condition.

    Reference Test Conditions: Input/Output current: 4 to 20mA; output load 250 ohms; 77°F (25°C).

    Input: 4 to 20mA input (each channel).

    Input Burden
    The voltage drop is a function of the input current and load resistance and is calculated as follows:
    Input Voltage Drop = 4.9V DC + (0.0212A x Rload).
     Example:  For Rload = 250 ohms, Vdrop = 10.2V DC.

    Output: 4-20mA DC output (each channel).

    Output Load: 0 to 525 ohms.

    Accuracy: Better than ±0.1% of output span. Error includes the combined effects of isolator repeatability, hysteresis, terminal point linearity and adjustment resolution.

    Calibration: One 15-turn potentiometer per channel, accessible from front of the unit.

    Ambient Temperature Effect: Less than ±0.01% of output span per °F (±0.018% per °C) over the ambient temperature range for reference test conditions. This specification includes the combined effects of zero and span over temperature.

    Output Ripple: Less than ±0.1% of the maximum output span.

    Bandwidth: -3dB at 2.2Hz, typical.

    Response Time: For a step input, the output reaches 98% of output span in less than 300mS, typical, into 250 ohms.

    Noise Rejection: Common mode: 110dB at 60Hz, typical.

    Diagnostics
    LED fault indicator: Lights for output open loop detection or load compliance problem.
    Field test points: An internal 10 ohm sense resistor provides test points for monitoring the output signal current during field maintenance with a voltmeter.

    Environmental

    Ambient Temperature
    Operating: -25 to 70°C (-13 to 158°F).
    Storage: -40 to 85°C (-40 to 185°F).

    Relative Humidity: 5 to 95%.

    Power Requirement
    Power is derived from the input signal loop.
    In the event of an open output circuit, the input loop voltage drop is limited below 20V, nominal.
    Isolator has reverse polarity protection.

    Isolation: 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): Designed to comply with EN61000-4-3 Level 3 (10V/m, 80 to 1000MHz AM and 900MHz keyed) and European Norm EN50082-1.

    Electromagnetic Field Immunity (EMI): Less than ±0.25% of output span effect under the influence of electromagnetic fields from switching solenoids, commutator motors, and drill motors.

    Electrical Fast Transient (EFT): Complies with EN61000-4-4 Level 3 (2KV) and European Norm EN50082-1.

    Surge Immunity: Complies with EN61000-4-5 Level 3 (2KV) and European Norm EN50082-1.

    Electrostatic Discharge (ESD): Complies with EN61000-4-2 Level 3 (8KV air, 4KV direct to the enclosure port) and European Norm EN50082-1.

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

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

    Physical

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

    Connectors (Removable Terminal Blocks): Wire Range: AWG #14-22 (AWG #12 stranded only).

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

    Dimensions
    1.05W x 4.68H x 4.35D inches.
    26.7W x 118.9H x 110.5D millimeters.

    Shipping Weight: 1 pound (0.45 Kg) packed.

  • Features & Benefits

    • Multiple channels on a single unit saves space and reduces costs.
    • Galvanic isolation eliminates ground loops, reduces noise, and blocks transient signals.
    • Independent channels prevent signal interaction and offer spares for later use.
    • Fault LEDs provide a clear visual warning of open or failed process loops.
    • Single calibration pot per channel enables one-step, precise calibration
    • Operating Temperature range 25 to 70°C (-13 to 158°F)
  • Tech Papers

    Why Do I Need Electrical Isolation? - 8500988 (Log in to view the file)
    Why do we need signal isolation? Acromag is in the business of signal conditioning. We manufacture circuits that amplify, isolate, filter, and convert one signal form to another. Most of these circuits also provide electrical isolation. However, added isolation has a cost. Thus, sometimes customers either question their need for isolation or fail to recognize...
    How to Select the Right Isolator - 8401045
    The Ins and Outs of Isolation: A Guide to Selecting the Right Isolator Acromag manufactures a variety of isolators to provide a cost-effective solution for many applications. The primary function of the isolator is to eliminate ground loops that may exist between two or more instruments. A classical application isolates the control room equipment (computers,...
    How to Choose a 4-20mA Isolator - 8400850
    Very often, the simple task of choosing an isolator requires more than just comparing the number of channels and the cost per point. To help you with this exercise, here are some concepts to know when you need to choose a 4-20 mA isolator. The lowest cost approach is a two-wire system using output loop-powered...
    How to Use Acromag 600T Series Isolated Transmitters - 8401028
    Application 1 Re-transmitting a signal from a two-wire loop to a second location. Solution Use either a model 651T-0600 (single channel) or 652T-0600 (dual channel) transmitter. Application 2 Splitting a signal from a two-wire loop: two outputs for different locations. Solution Use either a 653T-0600 (single input, dual output) or 652T-0600 (dual input, dual output)...
  • Specs & Data Sheets

    Manuals

    671T, 672T, 674T User Manual (Log in to download the file)

  • Accessories

    • Compare

      PS5R: Slim Line Power Supplies

      • 10W, 15W, 30W, 60W, 90W, 120W, and 240W models
      • Universal Input (85-264V AC / 100-370V DC)
      • Lightweight and compact size
       
      Select options
  • Additional information

    Additional information

    Weight 8 oz
    Dimensions 1.5 × 5 × 4.5 in
    Part Number

    671T-0600: Single I/O Channel, 672T-0600: Dual I/O Channel, 674T-0600: Quad I/O Channel

    Product Series

    600 Series

    Power

    Loop Power