This document describes the Model 352C33, a Platinum Stock Products, high-sensitivity, ceramic shear ICP® accelerometer. It includes an installation and operating manual, along with warranty, service, repair, and return policies.

Function Description

The Model 352C33 is an ICP® accelerometer designed for vibration measurement. ICP® sensors require constant current excitation for proper operation, typically supplied by PCB constant-current signal conditioners or other approved sources. The device provides an AC-coupled output signal compatible with most standard readout devices. It is suitable for various applications, including machinery condition monitoring, predictive maintenance, spot checks, and vibration trending.

Important Technical Specifications

Sensitivity: 100 mV/g (10.2 mV/(m/s²))
Measurement Range: ±50 g pk (±490 m/s² pk)
Frequency Range (±5%): 0.5 to 10,000 Hz
Frequency Range (±10%): 0.3 to 15,000 Hz
Resonant Frequency: ≥50 kHz
Broadband Resolution (1 to 10,000 Hz): 0.00015 g rms (0.0015 m/s² rms)
Non-Linearity: ≤1%
Transverse Sensitivity: ≤5%
Overload Limit (Shock): ±5000 g pk (±49000 m/s² pk)
Operating Temperature Range: -65 to +200 °F (-54 to +93 °C)
Excitation Voltage: 18 to 30 VDC
Constant Current Excitation: 2 to 20 mA
Output Impedance: ≤200 ohm
Output Bias Voltage: 7 to 12 VDC
Discharge Time Constant: 1.0 to 2.5 sec
Settling Time (within 10% of bias): <10 sec
Spectral Noise (1 Hz): 39 µg/√Hz (380 (µm/s²)/√Hz)
Sensing Element: Ceramic Shear
Housing Material: Titanium
Sealing: Hermetic
Size (Hex x Height): 0.44 in x 0.62 in (11.2 mm x 15.7 mm)
Weight: 0.20 oz (5.8 gm)
Electrical Connector: 10-32 Coaxial Jack, Side position
Mounting Thread: 10-32 Female
Mounting Torque: 10 to 20 in-lb (113 to 226 N-cm)

Optional Versions:

HT (High Temperature): Extends normal operation temperatures to -65 to +325 °F (-54 to +163 °C) with an excitation voltage of 22 to 30 VDC.
J (Ground Isolated): Offers electrical isolation (>10⁸ ohm) and different frequency ranges (9 kHz for ±5%, 14 kHz for ±10%) and resonant frequency (≥40 kHz).
T (TEDS Capable): Compliant with IEEE P1451.4 for digital memory and communication. Includes variations for LMS International (Free Format, Automotive, Aeronautical) and IEEE 1451.4. TEDS option adds 1.0 VDC to bias voltage.
W (Water Resistant Cable): Features a sealed integral cable with side electrical connection.

Usage Features

The manual details several mounting methods for the accelerometer:

Stud Mount: Recommended for permanent installations, providing high frequency response. Requires a smooth, flat mounting surface (63 µin finish) and proper torque (10 to 20 in-lb) for the mounting stud.
Adhesive Mount: Suitable for situations with space restrictions or convenience. Can be done directly to the test structure or via an adhesive mounting base. Requires a smooth, flat mounting surface (63 µin finish). Debonding agents are necessary for removal to prevent sensor damage.
Magnetic Mount: Convenient for quick, portable measurements, often used in machinery condition monitoring. Requires a smooth, flat mounting surface and proper magnet selection (flat or dual-rail). Caution is advised during installation to prevent high acceleration (g) levels that could damage the sensor.
Handheld or Probe Tip Mount: Not generally recommended for most applications due to questionable accuracy and repeatability, but can be useful for initial vibration location.

Cabling:

Proper cable selection is crucial; ICP® sensors can use ordinary two-wire or coaxial cables. Low-noise cables are essential for CE conformity.
Thread-locking compound can secure cable connections. Silicone rubber sealant, O-rings, or heat-shrink tubing can seal connections in harsh environments.
Cables should be routed to minimize stress on the sensor/cable connection and avoid physical damage or electrical noise (e.g., near high-voltage wires). Shielded cables should be grounded at one end only.

Powering:

ICP® sensors require constant current excitation (18 to 30 VDC, 2 to 20 mA).
Use only PCB constant-current signal conditioners or approved sources.
Never supply voltage to an ICP® accelerometer without a current-regulating diode or equivalent circuit, as this can cause damage not covered by warranty.
Signal conditioners often include meters or LEDs to monitor bias voltage, check operation, and detect cable faults.

Calibration:

Routine calibration is recommended to ensure measurement accuracy.
PCB Piezotronics offers ISO-9001 certified and A2LA accredited calibration services, traceable to N.I.S.T.
Special testing (e.g., sensitivity at extreme temperatures, phase response) is also available.
Back-to-Back Calibration is the preferred method for determining the sensitivity of piezoelectric accelerometers, comparing the test sensor to a previously calibrated reference standard.

Maintenance Features

Routine Maintenance: Includes cleaning electrical connectors, housings, and mounting surfaces with solutions that will not harm the material. Avoid liquids migrating into non-hermetically sealed devices.
Repair: User servicing or repair is not recommended and may void the factory warranty. Equipment should be returned to PCB Piezotronics for repair.
Total Customer Satisfaction: PCB Piezotronics guarantees to repair, replace, exchange, or refund the purchase price of any product if the customer is not completely satisfied.
Returning Equipment: Contact a distributor or customer service representative to obtain a Return Materials Authorization (RMA) number before returning any equipment. Include a Purchase Order for repair if the item is outside warranty or if the repair cost exceeds 50% of the replacement cost.

PCB Piezotronics PCB-352C33 - Page 4