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DC Input, Dual Channel Isolators AP4390, AP4391, AP4392

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The field configurable AP4390 series dual channel isolators offer wide ranging input and output capability for scaling and transmitting analog DC signals. The AP4390 series will accept input voltage spans from 10mV up to 100 volts, as well as input current spans from 1mA to 100mA. For a full scale output range, the input zero and span potentiometers enable 50% input zero and span adjustability. For example, the 0-10V input range can be elevated to 5-10V or compressed to 0-5V.

The AP4390 series offers 6 popular ouput ranges which are either positive voltages and currents (e.g. 0-5V, 0-10V, 0-1mA and 4-20mA) or bipolar voltages (-5 to 5V and -10 to 10V). The model number defines the ouput channel ranges as shown in Table 1.

The 4-20mA compliance is a powerful 20VDC per channel. All models in the AP4390 series accept bipolar inputs and each I/O channel offers selectable normal or reverse acting operation (e.g. 4-20mA or 20-4mA).

Each Action Pak in the AP4390 series is a dual, three-port, industrial isolator -- both output channels are optically isolated from their respective input channels up to 1500 VDC. The two ASIC-based I/O channels are independently transformer isolated from the selectable 120/240VAC power supply


The Action Pak AP4390 series of field configurable isolators is useful in eliminating ground loops, converting signal levels and providing signal drive. The AP4390 series' dual channel design conserves installation space in high density applications and offers superior cost-benefit value over single channel isolators. The wide ranging capability of the AP4390s provides universal spare part coverage.

Diagnostic LED

The AP4390 series is equipped with dual function LED signal monitors. The green, top-mounted LED indicates line power and input signal status. Active line power is indicated by an illuminated LED. If the input signal is 10% above the full scale range, the LED will flash at 8Hz. Below 0%, the flash rate is 4Hz.


Each channel of the AP4390 series can be independently set for a wide variety of input and output ranges.



  • High Density 2-Channel Package Minimizes Installation Space

  • Eliminates Ground Loops with 1500V Input-to- Output, Channel-to-Channel Isolation

  • Easy Field Configurable Input Ranges: 10mV to 100V, 1mA to 100mA

  • Six (6) Configurable Output Ranges: 0-5V, 0-10V, 0-1mA, 4-20mA, -5 to 5V and -10 to 10V

  • Easy Plug-in Installation/Low Mean-Time-to- Repair

  • Selectable 120/240 VAC Operation


  • Diagnostic LEDs

  • Calibration

  • Specifications

  • Ordering Information

Factory Presets

The factory presets all inputs for 4-20mA. The preset for positive based output channels is 4-20mA and -10 to 10VDC for bipolar voltage output channels (as shown in Table 1). The supply power is configured for 120 VAC operation. For other I/O ranges, remove the four base screws and case to access the I/O cards.

Replace the cover before applying power.


1. Position input jumper “W1” for Current (I) or Voltage (V) input.

2. Set position 5 of the Input Range Selector for Unipolar or Bipolar
input operation.

Note: A bipolar range selection will double any range from Table 2 (e.g, 10V span = ±10V bipolar span)

3. Set position 6 of the Input Range Selector for Normal or Reverse operation. Reverse acting produces a decreasing output with an increasing input.
4. Using Table 2, configure positions 1 through 4 of the Input Range Selector for the desired maximum input. Round the desired maximum input value to the next highest range (e.g., 0-70V = 100V range).

WARNING: Do not change switch settings with power applied. Severe damage will result.


1. For the AP4390 channels A and B, and the AP4391 channel B, use Table 3 to configure the output selector switches for one of the four(4) standard output ranges.

2. For the AP4392 channels A and B, and the AP4391 channel B, position output jumper "W2" for -5 to 5V or -10 to 10V.


1. Configure the AC jumpers for either 120 or 240 VAC operation.


1. Connect the input to a calibrated DC voltage or current source and apply power. Wait 1 hour for
thermal stability before monitoring the voltage/current output.
2. Set the calibrator to the desired minimum input and adjust the Zero potentiometer for the desired minimum output.
3. Set the calibrator to the desired maximum input and adjust the Span potentiometer for the desired maximum output.
4. Repeat steps 2 and 3 for best accuracy.




Voltage Input (field configurable):

  • Full Scale Range: 10mV to 100V
    Impedance: >100K Ohms

  • Overvoltage: 400 Vrms, max(Intermittent); 264 Vrms, max (Continous)


Current Input (field configurable):

  • Full Scale Range: 1mA to 100mA
    Impedance: 20 Ohms, typical

  • Overcurrent: 170mArms, max
    Overvoltage: 60VDC


Common Mode (Input to Ground):
  • 1500VDC, max

  • Zero Turn-Up: 50% of full scale range
  • Span Turn-Down: 50% of full scale range

Voltage Output:

  • Output:: 0-5V, 0-10V, -5 to 5V, -10 to 10V

  • Drive: 10mA, max. (1K Ohms min. load @10V)


Current Output:

  • Output: 0-1mA, 4-20mA

  • Compliance: 0-1mA: 10V, max (10K Ohms max load) 4-20mA: 20V, max (1K Ohms max load)


LED Indication (green):
Input Range:>110% input: 8Hz flash <-10% input: 4Hz flash

Accuracy (Including Linearity, Hysteresis):


  • <20mV, <2mA: ±0.35% of full scale, typical, 0.5%, max

  • >20mV, >2mA: ±0.1% of full scale, typical, 0.2%, max


Response Time:
(10-90%) 200 mSec., typical


Stability (Temperature):

  • ±0.025% of full scale/°C, typical,

  • ±0.05%/°C, max.


Common Mode Rejection:

DC to 60Hz: 120dB


Isolation (Input to Output):

1500 VDC between channels, input, output and power


ESD Susceptibility:

Level 2 (4KV)


Humidity (Non-Condensing):

  • Operating: 15 to 95% (@ 45°C)

  • Soak: 90% for 24 hours (@ 65°C)


Temperature Range:

  • Operating: -15 to 60°C (5 to 140°F)

  • Storage: -25 to 70°C (-13 to 158°F)



  • Consumption: 4W typical, 6W max

  • Standard: selectable 120/240VAC, ±10%, 50-60Hz



  • AP4390: 0.66lbs

  • AP4391: 0.68lbs

  • AP4392: 0.68lbs



  • CSA certified per standard C22.2 No. M1982 (File No. LR42272).

  • UL recognized per standard UL508 (File No. E150323/E99775).

Ordering Information


1.Model: AP4390-0000 (ChA = I or V out; ChB = I or V out)

  • AP4391-2000 (ChA = I or V out; ChB = ±V out)

  • AP4392-2000 (ChA = ±V out; ChB = ±V out)

2.Option: U, see text

3.Line Power: 120/240VAC

4.Optional Factory Calibration (C620): specify input range, output range and power. (All power supplies are transformer-isolated from the internal circuitry.)

  • M801-0000 Retaining Spring

  • M011-A 11 pin Track Mount Socket

  • M004-0000 4 ft Long Channel Track

  • MD11-0000 11 pin DIN Mount Socket





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