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Surge Protection Type Digital Input Isolated Safety Barrier 
PHD-11TF-28+ 1 input and 1 output

Input: Switch contacts/proximity switches
Output: Transistor


    The isolated safety barrier with surge protection function of switch input transistor output, which isolates and transmits input signals from switch contacts or proximity switches in hazardous areas to of the safety zone with output transistor through the safety barrier. Line fault detection is achieved through LED on the top of the module. The dial switch of the module is used to set input and output in-phase or reverse control, as well as to enable or disable the line fault detection alarm indication function.

    This product requires independent power supply, with isolated power supply, input, and output terminals.


    Input in harzadous area
    Input signal Switch contacts/proximity switches
    The supply voltage of the sensor About 8V
    Switching rate  <5kHz
    Input/output characteristics:
    On site input current >2.1mA, the output is closed, indicating ON;
    When<1.2mA, the output is open circuit, indicating OFF
    Switched control between inverted phase and normal phase of outputs e-c When the dial switch K1 is at "ON", the transistor output e-c are in inverted phase
    When the dial switch K1 is at "OFF", the transistor output e-c are in normal phase
    When the K2 is at  "ON", the circut will select the red light LFD indication alarm function
    Output in safe area
    Output signal Relay and alarm relay (optional)
    Output characteristic NPN type transistor emitter or collector open circuit output
    Drive capability Output current ≤ 20mA (1.2k Ω), maximum internal current 100mA, equipped with short-circuit current protection
    Surge protection features:
    Nominal discharge current ln(8/20μs) 5kA
    Voltage protection level Up(8/20μs): 60V(line to line)
    Voltage protection level Up(8/20μs): 600V(line to ground)
    According to standards GB/T18802.21-2016(equivalent to 1EC61643-21:2012)
    Basic parameters
    Supply voltage 20~35VDC
    Power consumption <40mA(24V power supply, when the transistor is conducting)
    LED indicator  Green: Power indicator
    Yellow: Output transistor in normal working state
    Red: LFD indication, line fault alarm
    Temperature parameters Working temperature: -20℃ ~ +60℃,
    Storage temperature: -40℃ ~ +80℃
    Relative humidity 10%~95% RH no condensation
    Insulation strength Between intrinsically safe side and non-intrinsically safe side (≥3000VAC/min); between power supply and non-intrinsically safe side (≥1500VAC/min)
    Insulation resistance ≥100MΩ (between input/output/power supply)
    Electromagnetic compatibility According to IEC 61326-1 (GB/T 18268), IEC 61326-3-1
    MTBF 100000h
    Wire requirements Horizontal cutting surface ≥ 0.5mm2; Insulation strength ≥ 500V
    Applicable field equipments Field equipment such as dry contacts or NAMUR type proximity switch inputs that comply with DIN19234 standard
    Installation place Installed in a safe zone, it can be connected to intrinsic safety instruments in hazardous areas up to Zone 0, IIC, Zone 20, and IIIC
    Intrinsically safe certification
    Explosion proof mark [Ex ia Ga]lIC [Ex ia Da]lllC
    Explosion-proof standard GB/T3836.1-2021  GB/T3836.4-2021
    Terminals 3-4 Um:250V AC/DC Uo=10.5V DC lo=15mA
    Po=39.4mW Co=1.7μF Lo=165mH
    Certification body CQST(China National Quality Supervision and Test Centre for Explosion Protected Electrical Products)
    Shanghai lightning protection products testing center



    Connection wiring



    1. The power supply of the power rail is an optional function. Users need to specify the power supply mode when ordering. Please refer to attachment on page 89.

    Line Fault Detection

    Users can select the "ON" side of the switch at the top of the module to enable fault detection function and indicate an alarm through the red LED light. On site input current>7mA, short circuit alarm (SC); On site input current<0.1mA, open circuit alarm (LB). If the switch contact input requires fault detection function (wire breakage, short circuit), a 22k Ω resistor should be connected in parallel at both ends of the switch, and a 680 Ω resistor should be connected in series (as shown in the wiring diagram for switch contact II).