PXI-6233 Bank-Isolated Multifunction I/O Module
The PXI-6233 is a bank-isolated PXI multifunction data acquisition module designed for measurement and control applications in electrically noisy industrial environments. It combines 16 analog inputs, two analog outputs, six isolated digital inputs, four isolated sinking digital outputs and two 32-bit counter/timers in one PXI module.
The analog inputs provide 16-bit resolution and an aggregate sampling rate of up to 250 kS/s. Its digital channels are compatible with common 24 V industrial signals, allowing the PXI-6233 to monitor sensors, encoders and switches while controlling relays, valves, pumps and other external devices.
Key Features of the PXI-6233
- 16 single-ended or eight differential analog inputs
- 16-bit analog input resolution
- 250 kS/s maximum aggregate sample rate
- Software-selectable ±0.2 V, ±1 V, ±5 V and ±10 V ranges
- RSE, NRSE and differential input configurations
- Bank-isolated analog and digital I/O architecture
- Two 16-bit analog outputs
- ±10 V analog output range
- 500 kS/s maximum single-channel analog output rate
- 450 kS/s maximum rate per channel with both outputs active
- Six isolated digital input channels
- Four isolated sinking digital outputs
- 24 V industrial digital signal compatibility
- Two 32-bit counter/timers
- Analog and digital triggering
- PXI backplane timing and synchronization
- 37-pin D-Sub front connector
- NI-DAQmx software support
PXI-6233 Technical Specifications
| Product Model | PXI-6233 |
|---|---|
| Part Number | 779620-01 |
| Product Family | Isolated M Series multifunction DAQ |
| Bus Interface | PXI |
| Maximum Single-Ended Analog Inputs | 16 |
| Maximum Differential Analog Inputs | 8 |
| Input Configurations | RSE, NRSE and differential |
| Analog Input Resolution | 16 bits |
| Maximum Analog Input Sample Rate | 250 kS/s aggregate |
| Simultaneous Sampling | No; multiplexed analog input architecture |
| Analog Input Ranges | ±0.2 V, ±1 V, ±5 V and ±10 V |
| Analog Input FIFO | 4,095 samples |
| Analog Output Channels | 2 voltage outputs |
| Analog Output Resolution | 16 bits |
| Analog Output Range | ±10 V |
| Maximum Single-Channel Output Rate | 500 kS/s |
| Maximum Dual-Channel Output Rate | 450 kS/s per channel |
| Analog Output Current Drive | ±5 mA |
| Analog Output Impedance | 0.4 Ω typical |
| Digital Inputs | 6 isolated channels |
| Digital Outputs | 4 isolated sinking channels |
| Digital Signal Compatibility | 24 V industrial logic |
| Counter/Timers | 2 |
| Counter Resolution | 32 bits |
| Triggering | Digital start, reference and pause triggering |
| Isolation Architecture | Bank isolation between field I/O sections and the PXI system |
| Front Connector | 37-pin D-Sub |
| Operating Temperature | 0°C to 55°C |
| Storage Temperature | -40°C to 70°C |
| Operating Humidity | 10% to 90% RH, noncondensing |
| Module Format | 3U PXI |
| Weight | Approximately 142 g |
| Software Support | NI-DAQmx |
| Lifecycle Status | Discontinued with limited NI support |
PXI-6233 Part Number and Accessories
| Item | Part Number | Description |
|---|---|---|
| PXI-6233 | 779620-01 | Bank-isolated PXI multifunction DAQ module with analog and industrial digital I/O |
| SH37F-37M Cable | 778621-02 | 2 m shielded 37-pin female-to-male D-Sub cable |
| R37F-37M Cable | 779195-01 | 1 m low-cost unshielded 37-pin ribbon cable |
| SH37F-P-4 Cable | 778620-04 | 4 m shielded 37-pin D-Sub to pigtail cable for custom fixtures |
| CB-37F-HVD | 779491-01 | High-voltage DIN-rail screw-terminal connector block |
| CB-37FH | 778673-01 | Horizontal DIN-rail 37-pin D-Sub screw-terminal block |
| CB-37FV | 778672-01 | Vertical DIN-rail 37-pin D-Sub screw-terminal block |
| CB-37F-LP | 779353-01 | Low-profile 37-pin connector block for compact wiring |
| TB-2621 | 779444-01 | PXI-mounted high-voltage screw-terminal block |
Select cables and terminal accessories according to the required shielding, voltage rating, mounting method and field-wiring arrangement. The CB-37F-HVD or TB-2621 should be considered when the application requires the corresponding higher-voltage accessory rating.
Bank-Isolated Multifunction Architecture
The PXI-6233 separates its field I/O circuitry from the PXI computer system through bank isolation. This architecture helps protect measurement signals from ground loops, electrical noise and moderate ground-potential differences.
Bank isolation does not mean that every individual channel is isolated from every other channel. Channels within the same functional bank share a reference, while the complete bank is isolated from other specified sections and the PXI bus.
16 Analog Input Channels
The module provides as many as 16 single-ended analog inputs. It can alternatively be configured for up to eight differential measurements when improved rejection of common-mode noise is required.
Analog inputs can measure conditioned sensor outputs, control voltages, process signals and other voltage sources. The selected terminal configuration must match the grounding characteristics of the connected signal.
16-Bit Analog Input Resolution
The analog input converter provides 16-bit resolution, corresponding to 65,536 theoretical quantization levels across the selected input range. Choosing an appropriate range improves the effective resolution available for the signal.
Measurement accuracy is also affected by source impedance, noise, settling time, wiring, calibration and temperature. Shielded twisted-pair cables are recommended for signals routed through areas with significant electromagnetic interference.
250 kS/s Multiplexed Acquisition
The analog inputs share a multiplexed ADC with a maximum aggregate sampling rate of 250 kS/s. When several channels are included in one acquisition task, this rate is divided among the active channels.
For example, scanning ten channels at equal rates results in a maximum theoretical rate of approximately 25 kS/s per channel before accounting for settling and application-specific timing requirements.
Software-Selectable Input Ranges
The PXI-6233 supports bipolar analog input ranges of ±0.2 V, ±1 V, ±5 V and ±10 V. A smaller range provides finer voltage resolution for low-level signals, while the ±10 V setting accommodates standard instrumentation outputs.
The input signal, including noise and transient peaks, must remain within the selected range to prevent clipping. External attenuation or signal conditioning is required for voltages beyond the supported measurement range.
RSE, NRSE and Differential Measurements
Referenced single-ended mode measures each signal relative to the isolated analog ground. Nonreferenced single-ended mode uses a shared remote reference, while differential mode measures the voltage between a positive and negative input pair.
Differential wiring is generally preferred for low-level signals, long cable runs and sources located in noisy environments. Single-ended configurations provide more channel density when the signals share a suitable reference.
Two 16-Bit Analog Outputs
The PXI-6233 includes two 16-bit voltage output channels with a fixed ±10 V range. One output can update at up to 500 kS/s, while both channels can update at up to 450 kS/s per channel.
Analog outputs can generate control voltages, setpoints and stimulus waveforms. They provide a current drive of approximately ±5 mA and should be connected to high-impedance loads or external amplifiers when more current is required.
Six Isolated Digital Inputs
Six digital input channels support common industrial signal levels, including 24 V logic. They can monitor proximity sensors, limit switches, alarms, controller outputs and other field devices.
The digital input reference must be connected according to the required sourcing or sinking field-circuit arrangement. Verify the high- and low-level voltage requirements before connecting a sensor.
Four Sinking Digital Outputs
The four isolated digital outputs use a sinking architecture. When activated, an output provides a current path from the connected load toward the output bank return.
This low-side switching arrangement is commonly used with loads connected to a positive external field supply. Typical applications include relay coils, indicators, valves and compatible PLC inputs.
External Digital Field Supply
The sinking outputs require an external field supply and do not generate a 24 V load voltage from the PXI chassis. The load is connected between the positive field supply and the selected digital output.
The supply voltage, current capacity, output current and load characteristics must remain within the ratings of the module and wiring accessory. Use appropriate external fusing and current limiting.
Inductive Load Protection
Valves, pumps, contactors and relay coils can generate a high reverse voltage when switched off. Install an appropriate flyback diode, snubber or transient-voltage suppressor close to each inductive load.
External suppression reduces electrical interference and helps protect the output circuitry. Component selection should consider supply voltage, load current and the required release time of the controlled device.
Two 32-Bit Counter/Timers
Two 32-bit counter/timers support event counting, frequency measurement, period measurement, pulse-width measurement, pulse generation and encoder applications.
The counter terminals share the module’s isolated digital I/O connections. This allows the PXI-6233 to acquire signals from encoders, flow meters and other pulse-output sensors while maintaining isolation from the PXI system.
Encoder and Flow-Meter Measurements
Counter inputs can monitor quadrature encoders for position and direction information. They can also measure pulse trains produced by flow meters, tachometers and proximity sensors.
Check the sensor output voltage, maximum pulse frequency and wiring configuration. An external line receiver or signal conditioner may be required when the sensor output does not meet the module’s digital input requirements.
Digital Triggering
The PXI-6233 supports digital start, reference and pause triggering. An external event or PXI backplane signal can initiate acquisition, identify a reference point or temporarily pause a measurement operation.
Trigger routing through the PXI backplane helps coordinate the module with digitizers, waveform generators, switches and other compatible instruments without additional front-panel cables.
PXI Timing and Synchronization
The PXI-6233 can use PXI trigger lines, the PXI star trigger and the PXI 10 MHz reference clock for timing and synchronization. Multiple modules can share clocks and triggers when an application requires coordinated measurements.
Available synchronization accuracy depends on the timing configuration, chassis, modules and software. Configure the master and slave tasks explicitly in NI-DAQmx when coordinating several devices.
Typical PXI-6233 Applications
- Industrial process monitoring
- Automated test equipment
- Factory automation
- Machine monitoring and control
- 24 V sensor acquisition
- Encoder and position measurement
- Flow-meter monitoring
- Proximity sensor acquisition
- Valve and relay control
- Pump-control systems
- Electromechanical testing
- Production-line test fixtures
- Laboratory control systems
Industrial Process Monitoring
The analog inputs can monitor conditioned pressure, temperature, force, displacement and flow signals. Digital inputs can record alarms and machine states while counter channels measure pulse-output sensors.
Bank isolation helps reduce the influence of industrial ground noise on the PXI controller. External signal conditioning may still be necessary for thermocouples, strain gauges, current-loop transmitters and other specialized sensors.
Machine and Fixture Control
Two analog outputs can provide setpoints to drives and controllers, while the sinking digital outputs operate external relays and compatible low-current loads. Digital inputs can confirm fixture position, interlock state or actuator completion.
Safety-critical interlocks should not depend exclusively on application software or a general-purpose DAQ module. Use dedicated safety hardware when required by the machine risk assessment.
Automated Production Testing
The PXI-6233 can combine voltage measurements and field-device control in a single automated test fixture. Test software can apply analog setpoints, energize relays, read device voltages and verify digital status without manual rewiring.
PXI backplane synchronization allows the module to operate alongside digital multimeters, programmable power supplies, switch modules and other test instruments.
NI-DAQmx Software Support
The PXI-6233 is controlled through the NI-DAQmx driver. NI-DAQmx provides functions for analog input, analog output, digital I/O, counter measurements, triggering and PXI signal routing.
The driver supports LabVIEW, LabWindows/CVI, C/C++ and compatible .NET development environments. NI Measurement & Automation Explorer can identify the module, perform self-tests and create basic test panels.
PXI-6233 Lifecycle Status
The PXI-6233 is discontinued and NI lists it with limited support. It remains useful for maintaining established test systems whose software, cables and fixtures were designed for this model.
Before purchasing a replacement or spare module, verify the required driver version, operating-system compatibility, calibration requirements and condition of the available hardware.
PXI-6233 Troubleshooting
The PXI-6233 is not detected in NI MAX
Confirm that the module is fully inserted into a compatible PXI slot. Check chassis power, controller communication and NI-DAQmx installation, then restart the system and refresh the device list.
An analog input reads the wrong voltage
Verify the selected input range, terminal configuration and channel reference. Check whether the signal should use RSE, NRSE or differential wiring and confirm that its common-mode voltage remains within the module limits.
Measurements become inaccurate when scanning several channels
Increase the ADC convert interval to provide more settling time. High source impedance and large voltage differences between adjacent channels can require a slower channel-scanning rate.
An analog output does not reach the programmed voltage
Disconnect the load and test the output again. Confirm that the load does not require more than the available ±5 mA drive current and that the commanded voltage remains inside the ±10 V range.
A digital input does not detect a 24 V signal
Check the input-bank reference, sensor wiring and field-supply polarity. Confirm that the sensor output reaches the specified high and low voltage thresholds.
A sinking output does not energize the load
Verify that an external field supply is connected and that the load is wired between its positive terminal and the selected output. Check output polarity, load current and the output-bank return connection.
An output turns off when switching a relay or valve
Check for excessive load current and inductive voltage transients. Install appropriate flyback or transient suppression and confirm that the load remains within the output rating.
Counter measurements are unstable
Inspect the encoder or pulse signal for noise, slow edges and incorrect voltage levels. Use shielded wiring and verify the counter terminal assignments in the NI-DAQmx configuration.
Ground noise affects analog measurements
Use differential inputs and individually shielded twisted-pair wiring. Connect the cable shield at one suitable point and keep analog wiring separated from motors, contactors and variable-frequency drives.
PXI-6233 Comparison with Similar Isolated DAQ Modules
| Model | Analog Input Configuration | Analog Outputs | Digital I/O | Best Suited For |
|---|---|---|---|---|
| PXI-6230 | 8 AI, 16-bit, 250 kS/s | 4 AO | 6 DI and 4 sourcing DO | Systems requiring additional sourcing outputs and four analog outputs |
| PXI-6232 | 16 AI, 16-bit, 250 kS/s | None | 6 DI and 4 sinking DO | Isolated acquisition and sinking control without analog generation |
| PXI-6233 | 16 AI, 16-bit, 250 kS/s | 2 AO | 6 DI and 4 sinking DO | Mixed isolated measurement and sinking control |
| PXI-6238 | 8 AI, 16-bit, 250 kS/s | 2 AO | 6 DI and 4 sourcing DO | Systems requiring sourcing rather than sinking outputs |
| PXI-6239 | 16 AI, 16-bit, 250 kS/s | 2 AO | 6 DI and 4 sourcing DO | Higher input density with sourcing industrial outputs |
PXI-6233 vs PXI-6232
The PXI-6232 and PXI-6233 both provide 16 analog inputs, six digital inputs and four sinking digital outputs. The primary difference is that the PXI-6233 adds two 16-bit analog output channels.
Choose the PXI-6233 when the application must generate analog setpoints or waveforms. Choose the PXI-6232 when isolated analog acquisition and digital control are sufficient.
PXI-6233 vs PXI-6238
The PXI-6238 provides eight analog inputs, two analog outputs and four sourcing digital outputs. The PXI-6233 provides 16 analog inputs and four sinking outputs.
Select the PXI-6233 for additional analog input density and NPN-style low-side switching. Select the PXI-6238 for PNP-style high-side load control.
PXI-6233 vs PXI-6239
The PXI-6239 has a similar mixed-I/O configuration with 16 analog inputs and two analog outputs, but it uses sourcing digital outputs. The PXI-6233 uses sinking outputs.
The correct model depends primarily on the field-circuit design. Choose the PXI-6233 when the active output must provide a path to the field-supply return.
Recommended Related Products
- PXI-6230 Bank-Isolated Multifunction DAQ Module
- PXI-6232 16-Channel Isolated Multifunction DAQ Module
- PXI-6238 Isolated Multifunction DAQ Module with Sourcing Outputs
- PXI-6239 16-Channel Isolated Multifunction DAQ Module
- PCI-6233 Bank-Isolated Multifunction DAQ Device
- View More NI PXI and PXI Express Modules
- View More NI PCI and USB Data Acquisition Products
Selecting the Right Isolated Multifunction DAQ Module
Choose the PXI-6233 when the application requires 16 analog inputs, two analog outputs, industrial 24 V digital inputs and sinking digital outputs in a bank-isolated PXI architecture.
Select the PXI-6232 when analog outputs are unnecessary. Choose the PXI-6238 or PXI-6239 when sourcing digital outputs are required, or the PXI-6230 when additional analog output channels are more important than input density.
Why Choose the PXI-6233?
- Combines analog acquisition, generation and industrial digital control
- Provides 16 single-ended or eight differential inputs
- Offers 16-bit resolution and 250 kS/s acquisition
- Includes two 16-bit ±10 V analog outputs
- Interfaces with common 24 V digital signals
- Provides four sinking outputs for low-side load control
- Includes two 32-bit counter/timers
- Reduces ground-loop and electrical-noise problems
- Supports PXI timing and trigger routing
- Integrates with NI-DAQmx applications
Frequently Asked Questions
What is the PXI-6233?
The PXI-6233 is a bank-isolated PXI multifunction DAQ module with 16 analog inputs, two analog outputs, six digital inputs, four sinking digital outputs and two counter/timers.
What is the PXI-6233 part number?
The standard NI part number for the PXI-6233 is 779620-01.
How many analog inputs does the PXI-6233 provide?
It supports up to 16 single-ended analog inputs or eight differential analog inputs.
What is the maximum analog input sample rate?
The maximum aggregate analog input sampling rate is 250 kS/s. The rate is shared among channels in a multichannel task.
Does the PXI-6233 use simultaneous sampling?
No. It uses a multiplexed analog input architecture rather than an independent ADC for every channel.
Which analog input ranges are available?
The module provides software-selectable ±0.2 V, ±1 V, ±5 V and ±10 V input ranges.
Does the PXI-6233 have analog outputs?
Yes. It provides two 16-bit, ±10 V analog outputs with a maximum single-channel rate of 500 kS/s.
Are the digital outputs sourcing or sinking?
The PXI-6233 has four sinking digital outputs. An active output provides a current path toward the field-supply return.
Can the digital I/O work with 24 V signals?
Yes. Its isolated digital inputs and outputs are designed for common industrial signal levels, including 24 V systems, within the published ratings.
Does the PXI-6233 provide channel-to-channel isolation?
No. It uses bank isolation. Channels within a functional bank share a reference and are not individually isolated from one another.
How many counters are included?
The module provides two 32-bit counter/timers for encoder, frequency, period, pulse and event-counting applications.
Which connector does the PXI-6233 use?
The front panel has a 37-pin D-Sub connector compatible with suitable SH37F-37M cables and 37-pin terminal accessories.
Which software controls the PXI-6233?
The PXI-6233 is supported by NI-DAQmx and can be used with LabVIEW, LabWindows/CVI, C/C++ and compatible .NET environments.
Is the PXI-6233 discontinued?
Yes. NI lists the PXI-6233 as discontinued with limited support. Availability may depend on remaining inventory or tested secondary-market hardware.
Request a Quote for the PXI-6233
Contact us for current availability, condition, lead time and project pricing for the PXI-6233 Bank-Isolated Multifunction I/O Module. We can also help identify compatible 37-pin cables, high-voltage terminal blocks, PXI chassis and related sourcing or sinking isolated DAQ modules.
