NI SCXI-1349 Adapter Connection Guide

NI SCXI-1349 Shielded Cable Adapter: A Reliable Bridge for Connecting SCXI Systems to DAQ Devices

In modern testing and measurement systems, the connection quality between signal conditioning modules and data acquisition devices directly affects the accuracy of measurement results and the reliability of the system. The SCXI-1349 shielded cable adapter launched by National Instruments is specifically designed to connect the SCXI signal conditioning system to 68 pin E-series DAQ devices (excluding the 61XXE series), providing a standardized, low-noise interface solution for multi-channel signal acquisition. This article will provide a comprehensive and in-depth technical analysis of SCXI-1349 from the aspects of adapter overview, installation steps, technical specifications, safety and electromagnetic compatibility requirements, etc.

Product Overview and Functional Positioning

SCXI-1349 is a compact connector assembly designed to simplify the interconnection between SCXI chassis and E-series DAQ devices. It integrates three key connectors:

68 pin front panel male connector: located on the front panel of the adapter, used to connect one end of a 68 pin shielded cable. The other end of the cable is connected to the DAQ device.

50 pin onboard male connector: located on the adapter printed circuit board, directly connected to the 50 pin female connector at the rear of the SCXI module. This is the physical and electrical interface between the adapter and the SCXI system.

50 pin bracket mounting female connector: located at the back of the adapter, typically used for expanding or connecting other accessories (may not be directly used in some configurations).

Compatibility Description:

Applicable DAQ devices: Any 68 pin E-series DAQ device, such as NI 6030E, 6040E, 6052E, 6070E, 6110E (note: except for 61XXE series, please refer to the latest compatibility list for details).

Applicable SCXI modules: all SCXI signal conditioning modules (such as analog input, analog output, digital I/O, thermocouple, strain, RTD, etc.) except for the SCXI switch module.

Applicable chassis: SCXI-1000, SCXI-1001, SCXI-1000DC.

The adapter comes with two screws to secure it to the threaded holes at the rear of the SCXI chassis, ensuring a secure connection.

Preparation and required components before installation

Before starting the installation, please ensure that the following hardware and tools are prepared:

A computer equipped with a 68 pin E-series DAQ device (PCI, PXI, or PCMCIA interfaces are available).

One SCXI chassis (SCXI-1000, SCXI-1001, or SCXI-1000DC).

At least one compatible SCXI module (non switch module).

SCXI-1349 shielded cable assembly (including cable adapter body and a 68 pin shielded cable).

Small flathead screwdriver (used for fixing screws).

SCXI-1349 Installation Guide (this document can refer to the electronic version).

Notes:

Before operating any hardware, be sure to turn off the power of the SCXI chassis and unplug the power cord.

Ensure that all equipment is placed on a stable, static free workbench.

Avoid operating in flammable and explosive environments.

Detailed installation steps

The following steps correspond to Figure 2 and Figure 3 in the document, and following the correct sequence can ensure reliable system connection.

Step 1: Install the SCXI module into the chassis

Confirm that the power supply of the SCXI chassis has been turned off and the power cord has been unplugged.

Slide the SCXI module along the module rail into any slot of the chassis (Slot 1 to Slot 4 or Slot 12, depending on the chassis model), ensuring that the bottom of the module is fully engaged with the backplane connector.

Tighten the fixing screws on the front panel of the module and secure it to the threaded strip at the front of the chassis.

Repeat this operation until all required modules are installed.

Step 2: Identify the target module

According to the system design, determine which SCXI module will be connected to the DAQ device through SCXI-1349. Usually, in a single box system, an adapter can be used to connect one module; In multi chassis or multi module systems, it is necessary to determine the correct module address and routing configuration according to the SCXI Quick Start Guide.

Step 3: Connect the adapter to the SCXI module

Align the 50 pin female connector at the rear of SCXI-1349 with the 50 pin male connector at the rear of the SCXI module (pay attention to the direction, the connector has a foolproof design).

Smooth insertion, ensuring complete insertion.

Use the two screws that come with the adapter to secure the adapter to the corresponding threaded holes at the rear of the SCXI chassis. After tightening by hand, a flat screwdriver can be used to apply appropriate force, but do not overtighten.

Step 4: Connect the shielded cable

Take out a 68 pin shielded cable (usually a twisted pair shielded cable, with the length selected according to actual needs).

Insert either end of the cable into the 68 pin male connector on the front panel of SCXI-1349, and tighten the finger screws on both sides of the cable connector to ensure reliable grounding.

Insert the other end of the cable into the I/O connector of the 68 pin E-series DAQ device on the computer or PXI chassis, and tighten the screw as well.

Step 5: Final inspection and power on

Check if all connections are secure and if the screws are tightened.

Confirm that no metal foreign objects have fallen into the interior of the chassis.

Reinsert the SCXI chassis power cord and turn on the chassis power switch.

Open the computer and enter the Measurement&Automation Explorer (MAX) to verify if the SCXI module is correctly recognized.

Attention: During the entire installation process, do not insert or remove the SCXI-1349 adapter or module while the chassis is powered on, as this may cause equipment damage.

Technical specifications

The design of SCXI-1349 meets the requirements of industrial grade data acquisition systems, and its main specifications are as follows.

Analog input characteristics

Maximum operating voltage: 30 Vrms, 42 Vpk, 60 VDC (signal+common mode voltage). This means that the voltage range that the adapter itself can withstand is limited, and when connecting to higher voltage field signals, the SCXI module's built-in isolation or attenuation function must be used.

Environmental specifications

Working temperature: 0 ° C to 50 ° C

Storage temperature: -20 ° C to 70 ° C

Relative humidity: 10% to 90%, no condensation

Safety Certification

Design standards: Complies with IEC 61010-1, UL 3111-1, and CAN/CSA C22.2 No. 1010.1 (Safety Standards for Electrical Measurement and Testing Equipment).

Altitude: up to 2000 meters.

Installation category: Class I (CAT I, suitable for circuits not directly connected to the main power supply).

Pollution level: Level 2 (only non-conductive pollution, occasional temporary conductivity may occur due to condensation).

Electromagnetic Compatibility (EMC)

Radiation emission: EN 55011 Class A (at 10 meters), FCC Part 15A (above 1 GHz).

Immunity: assessed to comply with EN 61326-1:1997 A1:1998 Table 1.

Compliance Mark: CE, C-Tick, FCC Part 15 Class A.

Important note: To achieve complete EMC/EMI compliance, shielded cables (i.e. 68 pin shielded cables included with SCXI-1349) must be used for operation. Unshielded cables may result in excessive radiation or decreased immunity.

Precautions for safe operation and maintenance

As a key component connecting on-site signal and measurement systems, the safe use of SCXI-1349 is crucial. The following excerpt and extension of the security guidelines in the document:

Prohibited in hazardous environments: Do not operate this equipment in explosive environments or places with flammable gases or vapors.

Damaged equipment must not be used: If the adapter shows obvious damage such as broken casing, damaged connector, moisture or liquid ingress, it should be immediately stopped from use and inspected by trained personnel or sent back to NI for repair.

Unauthorized modification is prohibited: Do not replace unauthorized components or modify the internal circuit of the adapter. Any unauthorized modification may introduce electric shock hazards or damage safety features.

Signal insulation requirements: Users must perform insulation treatment on all signal connections that may come into contact with the highest voltage. Even if the SCXI module itself provides isolation, it should be ensured that exposed wires do not accidentally touch.

Do not exceed the rated value: The signal (including power signal to ground) connected to the adapter must not exceed the maximum signal rating listed in this document, otherwise it may cause electric shock, fire, or damage to all connected boards, chassis, and computers.

Cleaning method: When cleaning the adapter, a soft non-metallic brush should be used to gently brush away any floating dust. For stubborn pollutants, a hard non-metallic brush can be used. After cleaning, it is necessary to ensure that the adapter is completely dry and free of residual pollutants before it can be put back into use.

Supporting chassis requirements: SCXI-1349 must be used in conjunction with UL listed SCXI chassis (such as SCXI-1000, SCXI-1001, SCXI-1000DC) to meet the overall system's safety certification requirements.

Common application scenarios

SCXI-1349 is commonly used in the following system architectures:

Single module single channel system: An SCXI module is directly connected to an E-series DAQ device through an adapter for high-precision measurement of small signals (such as high-resolution thermocouple measurement).

Multi module multiplexing system: Multiple SCXI modules are installed in the same chassis, and signals are multiplexed to the output of one module through the backplane bus, and then connected to DAQ devices through SCXI-1349. In this mode, one analog input channel of the DAQ device can sequentially access multiple channels of multiple modules.

Parallel mode system: If it is necessary to collect independent signals from multiple modules simultaneously, an SCXI-1349 adapter and independent DAQ devices can be configured for each module (the computer needs to have multiple DAQ devices). In this mode, each module directly corresponds to an analog input channel of a DAQ device, achieving the highest parallelism.

Troubleshooting

If the module cannot be recognized or data cannot be read properly after installation, it is recommended to check in the following order:

Confirm that the SCXI chassis power is turned on and the power indicator light is on.

Refresh the device list in MAX and check if SCXI chassis and modules are detected.

Check if the connection between SCXI-1349 and the module is fully inserted and if the screws are tightened.

Check if the connection at both ends of the 68 pin cable is secure and if there is any obvious damage to the cable.

Confirm that the SCXI module used is not a switch module (not supported by SCXI-1349).

Try replacing the known good 68 pin cable for testing.