PCI-6236 Isolated Current-Input Multifunction DAQ Device
The PCI-6236 is an isolated M Series multifunction data acquisition board designed for industrial current-loop measurement and voltage-based control. It provides four differential ±20 mA analog inputs and four 16-bit ±10 V analog outputs.
The board also includes six digital inputs, four digital outputs, two 32-bit counters and hardware triggering. Bank isolation helps separate field-side signals from the computer bus and reduces problems caused by differences in electrical ground potential.
Key Features of the PCI-6236
- Four differential current-input channels
- ±20 mA input range
- 16-bit analog input resolution
- 250 kS/s aggregate input sampling
- Four 16-bit voltage outputs
- ±10 V analog output range
- Up to 500 kS/s on one analog output
- Six fixed-direction digital inputs
- Four fixed-direction digital outputs
- Two 32-bit counters/timers
- Bank-isolated analog and digital architecture
- 700 kHz analog input bandwidth
- 37-pin D-Sub connectivity
- NI-DAQmx software support
PCI-6236 Technical Specifications
| Product Model | PCI-6236 |
|---|---|
| Product Series | Isolated M Series DAQ |
| Bus Interface | PCI |
| Analog Inputs | 4 differential current inputs |
| Input Range | ±20 mA |
| ADC Resolution | 16 bits |
| Maximum Input Sample Rate | 250 kS/s aggregate |
| Input Impedance | 92 Ω typical in parallel with 100 pF |
| Input Bandwidth | 700 kHz |
| Overcurrent Limit | ±40 mA maximum |
| Analog Outputs | 4 voltage outputs |
| DAC Resolution | 16 bits |
| Analog Output Range | ±10 V |
| Maximum Output Rate | 500 kS/s using one channel; 400 kS/s/ch using four |
| Output Drive | ±5 mA |
| Digital Inputs | 6 |
| Digital Outputs | 4 |
| Counters/Timers | 2 × 32-bit |
| I/O Connector | 37-pin D-Sub |
| Calibration Interval | 1 year |
| Operating Temperature | 0°C to 55°C |
PCI-6236 Part Number and Accessories
| Item | Part Number | Description |
|---|---|---|
| PCI-6236 | 779621-01 | Four-channel isolated current-input PCI multifunction DAQ |
| SH37F-37M Cable | Length dependent | Shielded 37-pin D-Sub DAQ cable |
| 37-Pin Terminal Block | Configuration dependent | Provides field-wiring access to the card signals |
| Loop Power Supply | User supplied | Powers two-wire current transmitters when required |
| RTSI Cable | Configuration dependent | Routes synchronization signals between PCI devices |
Current-loop transmitters may be active or loop powered. Determine the transmitter type before wiring the PCI-6236, and never allow the current to exceed the specified ±40 mA protection limit.
Direct ±20 mA Current Measurement
The four inputs measure current directly without requiring an external shunt resistor. Their differential configuration is suited to common industrial transmitter and process-loop signals.
When measuring a conventional 4–20 mA transmitter, the application can convert the measured current into pressure, flow, level, temperature or another engineering unit.
Four Voltage Output Channels
The four ±10 V outputs can generate programmable control references, actuator commands and simulated sensor signals. Maximum output drive is approximately ±5 mA, so high-current loads require external buffering.
Bank Isolation
Isolation separates the field-side I/O subsystem from the PCI computer bus. It does not mean that every input channel is isolated from every other channel. All common references and isolation groups must be reviewed during system design.
PCI-6236 Applications
- 4–20 mA process monitoring
- Industrial transmitter acquisition
- Process-control system testing
- Valve and actuator control
- PLC and controller simulation
- Automated production testing
- Industrial data logging
- Sensor calibration systems
- Hardware-in-the-loop testing
- Ground-loop reduction
- Research and laboratory automation
- Legacy PCI control-system maintenance
Process Transmitter Monitoring
The current inputs can acquire four industrial transmitters directly. Software can apply scaling equations and alarms according to each transmitter’s 4–20 mA measurement range.
Controller and PLC Testing
Voltage outputs can simulate analog signals while digital and counter functions reproduce status and timing events. This supports automated testing of industrial controllers and input modules.
PCI-6236 Installation Workflow
Step 1: Verify the PCI Computer
Confirm availability of a conventional PCI slot and a supported operating system and NI-DAQmx combination.
Step 2: Install the PCI-6236
Shut down the computer, insert the card and secure the bracket.
Step 3: Connect the D-Sub Accessory
Use a compatible shielded 37-pin cable and terminal block. Confirm the current-input polarity and ground references.
Step 4: Wire the Current Loops
Determine whether each transmitter provides its own loop power or requires an external supply. Add appropriate fusing and current limitation.
Step 5: Configure NI-DAQmx
Create current-input channels with the ±20 mA range and voltage-output channels with the required limits.
Step 6: Validate with a Calibrator
Apply known current levels such as 4 mA, 12 mA and 20 mA and confirm the resulting software scaling.
Step 7: Test the Outputs
Measure the analog outputs with a high-impedance meter before connecting them to the final load.
PCI-6236 Troubleshooting
A current input always reads zero
Check loop continuity, transmitter polarity and loop power. A two-wire transmitter requires a suitable external supply.
The current reading is lower than expected
Check the total loop resistance, supply voltage and transmitter compliance voltage. Inspect wiring for unintended parallel current paths.
An analog output cannot reach the programmed voltage
The load may require more than the available ±5 mA drive. Disconnect the load and test with a high-impedance meter.
The card reports an overrange condition
Confirm that the current remains within ±20 mA for normal measurement. Currents beyond ±40 mA can permanently damage the input circuitry.
Measurements contain industrial noise
Use twisted shielded wiring, separate signal cables from motor drives and verify the isolation and grounding arrangement.
PCI-6236 Comparison
| Model | Analog Configuration | Best Suited For |
|---|---|---|
| PCI-6236 | 4 current AI and 4 voltage AO | Current acquisition with voltage control |
| PCI-6238 | 8 current AI without analog outputs | Higher-density current acquisition |
| PCI-6239 | 8 current AI and 2 current AO | Current-loop measurement and generation |
| PCI-6233 | 16 voltage AI and 2 voltage AO | Isolated voltage-based systems |
Recommended Related Products
- PCI-6239 Isolated Current I/O DAQ
- PCI-6233 Isolated Voltage DAQ
- PXI-6238 Isolated Current-Input Module
- View More NI PCI and USB DAQ Products
Frequently Asked Questions
What does the PCI-6236 measure?
It provides four differential current inputs with a fixed ±20 mA measurement range.
Does the PCI-6236 provide current outputs?
No. Its four analog outputs generate ±10 V voltage signals. Select the PCI-6239 when current output is required.
Can it measure a 4–20 mA transmitter directly?
Yes, provided the loop is wired and powered correctly and remains within the device’s electrical limits.
How many counters does it provide?
The PCI-6236 includes two 32-bit general-purpose counters/timers.
What is the PCI-6236 part number?
The standard ordering part number is 779621-01.
Request a Quote for the PCI-6236
Contact us for current availability and project pricing for the PCI-6236 Isolated Current-Input Multifunction DAQ Device. We can also help select cables, terminal blocks and suitable current-loop DAQ alternatives.
