PCI-6239 Isolated Current Input and Output DAQ Device
The PCI-6239 is an isolated M Series multifunction data acquisition board designed for industrial current-loop measurement and generation. It provides eight differential ±20 mA analog inputs and two programmable 0–20 mA current outputs.
The board also includes six industrial digital inputs, four sinking digital outputs, two 32-bit counters and hardware timing resources. Its combination of current acquisition and generation makes it suitable for process-instrument testing, transmitter monitoring and controller simulation.
Key Features of the PCI-6239
- Eight differential current-input channels
- ±20 mA analog input range
- 16-bit input resolution
- 250 kS/s maximum aggregate input rate
- Two programmable current outputs
- 0 mA to 20 mA output range
- 16-bit current-output resolution
- 500 kS/s maximum single-channel output rate
- Six 0 V to 30 V industrial digital inputs
- Four sinking industrial digital outputs
- Two 32-bit counters/timers
- Input and output bank isolation
- 37-pin D-Sub front connector
- NI-DAQmx software support
PCI-6239 Technical Specifications
| Product Model | PCI-6239 |
|---|---|
| Product Series | Isolated M Series DAQ |
| Bus Interface | PCI |
| Analog Inputs | 8 differential current-input channels |
| Input Range | ±20 mA |
| ADC Resolution | 16 bits |
| Maximum Input Rate | 250 kS/s aggregate |
| Input Impedance | 92 Ω ±10% in parallel with 100 pF |
| Input Bandwidth | 700 kHz |
| Maximum Protected Current | ±40 mA |
| Analog Outputs | 2 current-output channels |
| Output Range | 0 mA to 20 mA |
| DAC Resolution | 16 bits |
| Maximum Output Rate | 500 kS/s on one channel; 450 kS/s/ch using two |
| External Output Supply | 10 VDC to 30 VDC |
| Maximum Resistive Load | Up to 1 kΩ with a 24 V supply |
| Digital Inputs | 6 industrial inputs |
| Digital Outputs | 4 sinking outputs |
| Counters/Timers | 2 × 32-bit |
| I/O Connector | 37-pin D-Sub |
| Calibration Interval | 1 year |
PCI-6239 Part Number and Accessories
| Item | Part Number | Description |
|---|---|---|
| PCI-6239 | 779625-01 | Eight-input, two-output isolated current I/O PCI device |
| SH37F-37M Cable | Length dependent | Shielded D-Sub cable for signal connections |
| 37-Pin Terminal Block | Configuration dependent | Provides screw-terminal access to field wiring |
| Current-Output Supply | User supplied | Regulated 10 VDC to 30 VDC external supply |
| Loop Calibration Resistor | Application dependent | Used when independently verifying current-output operation |
The current outputs require an external 10 VDC to 30 VDC supply. Available load resistance depends on the supply voltage, wiring resistance and the module’s internal voltage drop.
Eight Direct Current Inputs
The eight differential inputs measure signals within ±20 mA. They are suitable for conventional 4–20 mA transmitters as well as bipolar current signals within the specified range.
Overcurrent protection must not be treated as a normal operating range. Current exceeding ±40 mA can permanently damage the device.
Two Programmable 0–20 mA Outputs
The analog outputs can simulate process transmitters, provide current commands or stimulate controller inputs. They support static values and hardware-timed waveform operation.
With a 24 V external supply, the supported resistive load can be as high as approximately 1 kΩ under the specified conditions. Cable and terminal resistance are part of the total load.
Industrial Digital I/O
Six inputs accept industrial signals between 0 V and 30 V. Four outputs use sinking connections for operating compatible external loads.
PCI-6239 Applications
- 4–20 mA transmitter testing
- Industrial process monitoring
- Process-controller simulation
- PLC analog-input testing
- Sensor and instrument calibration
- Valve and actuator control testing
- Automated production testing
- Industrial current-loop data logging
- Hardware-in-the-loop simulation
- Industrial digital control
- Ground-loop reduction
- Legacy PCI system maintenance
Transmitter Simulation
The two current outputs can simulate field transmitters during PLC, DCS and controller testing. Software can generate normal readings, alarm states and changing process conditions automatically.
Current-Loop Monitoring
Eight input channels allow several transmitters to be monitored by one PCI device. Acquired current values can be scaled into the corresponding engineering units.
PCI-6239 Installation Workflow
Step 1: Install the PCI Device
Power down the computer, install the PCI-6239 in a supported slot and secure its bracket.
Step 2: Install NI-DAQmx
Use a driver release that supports the card and the computer’s operating system.
Step 3: Connect the D-Sub Cable
Attach a compatible shielded cable and terminal block. Check every connection against the official pinout.
Step 4: Wire the Input Loops
Confirm transmitter polarity, loop-power source and current return paths before energizing the system.
Step 5: Connect the Output Supply
Provide a regulated 10 VDC to 30 VDC external supply for the current outputs and calculate the permitted load resistance.
Step 6: Configure NI-DAQmx
Create current-input and current-output channels with appropriate scaling and safety limits.
Step 7: Verify with a Calibrator
Test representative current values before connecting the production controller or process equipment.
PCI-6239 Troubleshooting
The current output remains at zero
Check the external output supply, output-enable state, load wiring and AO ground connection.
The output cannot reach 20 mA
The load resistance may be too high for the selected supply voltage. Include cable and terminal resistance when calculating loop compliance.
An input reads zero even though the transmitter is active
Inspect loop continuity and polarity. Verify that the transmitter current actually passes through the PCI-6239 input terminals.
A sinking digital output does not operate the load
Confirm external field power and correct sinking-output wiring. Check whether the load current exceeds the simultaneous-output rating.
The current measurement is unstable
Inspect shielding, loop grounding, power-supply noise and nearby inverter or motor cables. Average readings only after eliminating wiring faults.
PCI-6239 Comparison
| Model | Analog Configuration | Best Suited For |
|---|---|---|
| PCI-6239 | 8 current AI and 2 current AO | Current-loop measurement and simulation |
| PCI-6238 | 8 current AI without current output | Current acquisition-only systems |
| PCI-6236 | 4 current AI and 4 voltage AO | Current sensing with voltage control outputs |
| PCI-6233 | Voltage AI and voltage AO | Isolated voltage measurement and control |
Recommended Related Products
- PCI-6238 Isolated Current-Input DAQ
- PCI-6236 Multifunction Current-Input DAQ
- PCI-6233 Isolated Voltage DAQ
- View More NI PCI and USB DAQ Products
Frequently Asked Questions
What is the PCI-6239?
The PCI-6239 is an isolated PCI DAQ board with eight current inputs and two programmable current outputs.
What is the analog input range?
Each differential analog input supports a ±20 mA range.
What is the current output range?
The two analog outputs can generate current from 0 mA to 20 mA.
Do the current outputs require external power?
Yes. A 10 VDC to 30 VDC external supply is required.
What is the PCI-6239 part number?
The standard ordering part number is 779625-01.
Request a Quote for the PCI-6239
Contact us for availability and pricing for the PCI-6239 Isolated Current Input and Output DAQ Device. We can also help select compatible terminal accessories and replacement current-loop hardware.
