I. Basic Information

Model: PCI‑6255

Brand: National Instruments (NI)

Series: M-Series (ultra-high density, high speed, with AO, non-isolated)

Bus: PCI (3.3 V / 5 V compatible, full-length card)

Connector: 2 × 68-pin VHDCI

Driver: NI‑DAQmx

Operating Temperature: 0 ~ 55 °C

Isolation: No isolation (non-isolated type)

II. Analog Input AI (80 channels, ultra-high density and high speed)

Channels: 80 single-ended / 40 differential (software configurable) download.ni.com

Resolution: 16 bits, with no data loss guarantee download.ni.com

Maximum sampling rate: 1.25 MS/s (single channel); 750 kS/s (total for multiple channels) download.ni.com

Input range (software selectable): ±0.1 V, ±0.2 V, ±0.5 V, ±1 V, ±2 V, ±5 V, ±10 V download.ni.com

Coupling: DC download.ni.com

Input impedance: >10 GΩ || 100 pF download.ni.com

Maximum working voltage: ±11 V (signal + common mode) download.ni.com

CMRR: 100 dB @ DC~60 Hz download.ni.com

Input FIFO: 4,095 samples NI

III. Analog Output AO (2 channels)

Channels: 2 voltage outputs NI

Resolution: 16 bits NI

Maximum update rate: 2.86 MS/s (per channel) NI

Output range: ±5 V, ±10 V (software selectable)

Drive capability: ±5 mA (per channel)

Setup time: 10 µs (to ±0.5 LSB)

Load: minimum 1 kΩ

IV. Digital I/O (DIO, 24 channels)

Channels: 24 bidirectional TTL (non-isolated) NI

Level: 5 V TTL/CMOS (compatible with 3.3 V)

Maximum rate: 10 MHz

DO drive: maximum 10 mA/channel

Function: bidirectional input/output, event triggering, handshake signal, PFI

V. Counter / Timer

Channels: 2 32-bit general-purpose counters

Clock: 80 MHz internal base

Function: event counting, frequency / period measurement, pulse output, encoder, PWM

VI. Trigger and Synchronization

Trigger: AI analog edge / window trigger, PFI external digital trigger

Synchronization: RTSI bus multi-card synchronization

Data transfer: DMA, interrupt, programmable I/O

VII. Installation and Usage Tips Installation

Power off and disconnect, insert into the standard PCI full-length slot, and fix the retaining screws; after powering on, MAX will identify and self-check.

Wiring (2 × 68-pin VHDCI)

AI: Single-ended AIn + GND; Differential AI+/AI−, common mode ≤ ±11 V, no isolation against ground loop.

AO: AO + AGND, load ≥ 1 kΩ,严禁 short circuit.

DIO： TTL common ground， avoid long-distance parallel lines; PFI used as trigger / clock.

Software configuration (NI-DAQmx)

Sampling: High-speed synchronous scanning， 80 channels polled

Range： Weak signal priority ±0.1 V / ±0.2 V

Trigger： Common edge trigger (rising / falling) Notes for Attention

No isolation, not suitable for strong industrial interference / high voltage.

AI input must not exceed ±11 V, AO must not be short-circuited.

VIII. Core Features

80 high-speed AI (1.25 MS/s/16 bit) + 2 AO + 24 DIO + 2 counters, no isolation. download.ni.com

Full-length PCI card, dual 68-pin VHDCI, NI-DAQmx driver stable

Ultra-high density channels + analog output, suitable for multi-sensor parallel acquisition and closed-loop control

Applicable: Laboratory multi-channel measurement, sensor array, high-speed parallel acquisition, test systems requiring AO