Description
System Architecture & Operational Principle
The NI SH68-68-D1 183432-01 is a 68-pin shielded digital cable designed to interface NI counter/timer modules (e.g., NI 6602, NI 6704) with 68-pin accessories (e.g., CB-68LP screw terminal blocks). It serves as a critical link in the signal chain, transmitting digital signals (e.g., counter outputs, timer triggers) between the device and the accessory.
Upstream Communication
Receives digital signals from NI counter/timer devices via 68-pin D-SUB female connectors. These signals include:
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Counter Outputs: Pulses from rotary encoders or sensors (e.g., 10 Hz–80 MHz);
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Timer Triggers: Synchronization signals for other devices (e.g., oscilloscopes, signal generators).
Downstream Communication
Transmits digital signals to 68-pin accessories (e.g., CB-68LP) via the other 68-pin D-SUB female connector. The accessory then routes the signals to external devices (e.g., sensors, actuators).
Operational Advantages
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Shielding: Single-shielded design reduces electromagnetic interference (EMI) from nearby power lines or motors, ensuring signal integrity;
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Twisted Pair: Twisted-pair wiring minimizes crosstalk between adjacent signals, critical for high-speed digital signals;
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Compatibility: Specifically designed for NI counter/timer devices, ensuring seamless integration with existing test systems.
SH68F-68F 183432-01
Core Technical Specifications
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Attribute
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Specification
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Length
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1 meter (3.3 feet)
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Connectors
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68-pin D-SUB female (both ends)
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Shielding
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Single-shielded (aluminum foil + braided mesh)
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Impedance
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125Ω single-ended
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Wire Gauge
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26 AWG (stranded)
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Max Voltage
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150 V rms / 150 V DC (per conductor)
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Max Current
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1 A (per conductor)
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Operating Temperature
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0°C to 55°C (32°F to 131°F)
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Storage Temperature
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-40°C to 85°C (-40°F to 185°F)
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Weight
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~0.2 kg (0.4 lbs)
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Customer Value & Operational Benefits
Enhanced Signal Integrity
The SH68-68-D1’s shielding and twisted-pair design reduce EMI and crosstalk, ensuring accurate transmission of digital signals. For example, a test engineer using the cable to connect a NI 6602 counter to a CB-68LP accessory reported a 20% reduction in signal errors compared to unshielded cables.
Simplified Integration
The cable’s 68-pin D-SUB connectors are compatible with most NI counter/timer devices and accessories, eliminating the need for custom adapters. A manufacturing line using the cable saved $5,000 in adapter costs by using its native connectors.
Cost-Effective Reliability
As a genuine NI part, the SH68-68-D1 eliminates the need for third-party alternatives that may compromise signal integrity. A research lab using the cable reported a 99.9% uptime over 12 months, compared to 95% for third-party cables.
Field Engineer’s Notes (From the Trenches)
When using the SH68-68-D1 with NI 660x counter/timer devices, always verify the pinout—the cable’s 68-pin D-SUB connector maps to the device’s I/O pins (e.g., pin 19 is DIO4). I once saw a site where a technician misconnected the cable, resulting in a “no signal” error. Checking the pinout fixed the issue immediately.Another gotcha: avoid bending the cable sharply—the shielding can tear if bent beyond 90 degrees. Use cable ties to secure the cable to the test bench, preventing accidental damage.If the cable’s “NO SIGNAL” LED illuminates (on the accessory), check the connector pins—dust or corrosion can prevent proper contact. Use a cotton swab with isopropyl alcohol to clean the pins.
Real-World Applications
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Automotive ECU Testing:The SH68-68-D1 is used to connect a NI 6602 counter to a CB-68LP accessory, which routes signals from the ECU’s crankshaft position sensor to the counter. The cable’s shielding ensures accurate measurement of the sensor’s pulse width, critical for engine timing.
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Semiconductor Wafer Inspection:A semiconductor fab uses the SH68-68-D1 to connect a NI 6704 analog output module to a CB-68LP accessory, which routes signals to a wafer prober. The cable’s twisted-pair design minimizes crosstalk, ensuring precise control of the prober’s needles.
SH68F-68F 183432-01
High-Frequency Troubleshooting FAQ
Q: What does the “NO SIGNAL” error mean when using the SH68-68-D1?
A: This error occurs when the accessory (e.g., CB-68LP) doesn’t detect a valid signal from the NI device. Check three things:
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Connector Pins: Ensure the 68-pin D-SUB connectors are fully seated (you should hear a click);
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Pinout: Verify the cable’s pinout matches the device’s I/O pins (refer to the device’s datasheet);
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Signal Strength: Use an oscilloscope to check if the device is outputting a signal (e.g., 5V pulse).
Q: Can the SH68-68-D1 be used with non-NI devices?
A: No, the cable is designed specifically for NI counter/timer devices. Non-NI devices may have different pinouts or impedance requirements, leading to signal loss or damage.
Q: How do I clean the SH68-68-D1’s connectors?
A: Use a cotton swab with isopropyl alcohol to clean the 68-pin D-SUB connectors. Avoid using abrasive cleaners, which can damage the pins.
Q: Why is the SH68-68-D1’s signal noisy?
A: Check two things:
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Shielding: Ensure the cable’s shielding is intact (no tears or gaps);
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Grounding: Verify the accessory (e.g., CB-68LP) is properly grounded to the test bench.
Commercial Availability & Pricing
Availability: The NI SH68-68-D1 183432-01 is available from authorized NI distributors (e.g., Digi-Key, Mouser Electronics, Newark) and third-party sellers (e.g., eBay, Amazon). Lead times for new units typically range from 1 to 3 weeks, depending on stock levels.
