Q: What is the difference between compression and shear element accelerometers?

In compression sensors (HS-100, HS-105, HS-107) the PZT crystal works under compressive stress — simple, economical, wide frequency range; but more sensitive to base-strain and thermal transients. In shear sensors (HS-104, HS-150, HS-170, HS-180, HS-172, HS-173) the PZT crystal works under shear stress — significantly less sensitive to thermal shock, base strain and mounting surface flexure; premium technology. Decision: compression (HS-100) for standard industrial environments and wide frequency range; shear (HS-150/170) for thermal fluctuation, base-strain or high-frequency bearing/gear monitoring.

Q: What is the difference between IEPE/ICP and Line Drive (HS-107) sensors?

Most modern AC accelerometers use the IEPE (Integrated Electronics PiezoElectric) standard — constant current drive (typically 2-4 mA), 2-wire cable carrying both power and signal. ICP is PCB's trademarked name for IEPE. HS-107 uses Line Drive (Constant Voltage) — 24 Vdc CV drive, an older but still-used standard. Choose Line Drive (HS-107) when compatibility with legacy Bently Nevada, Vibrometer, Schenck, CSI, or SKF online systems is required. For new installations, choose modern IEPE series (HS-100, HS-150, HS-170, etc.).

Q: How do I choose between Top Exit and Side Exit variants?

Top Exit (HS-100, HS-150, HS-170 standard): Cable or connector exits from the top of the sensor. Standard for installations with adequate top clearance. Supports both Female (UNF) and Male (UNF, M6, M8, M10) mounting threads. Side Exit (HS-100S, HS-150S, HS-170S, HS-180S, HS-172, HS-173, etc.): Cable/connector exits 90° from the side. Ideal for tight spaces such as motor bearing housings, fan rotor undersides, gearbox sidewalls. Supports Male mounting threads only (02, 06, 08). Decision: Adequate top clearance? Top Exit. Roof/cover close? Side Exit.

Q: What does the HS-160 integrated-integrator velocity output do?

HS-100 and standard AC accelerometers output raw acceleration (g) signal ; converting it to velocity (mm/s) requires mathematical integration inside the vibration analyzer. HS-160 has an integrated analog integrator inside the sensor — its AC output is directly velocity (mm/s or in/s). Advantage: no extra integration step in online systems doing ISO 10816 velocity-based monitoring or in portable analyzers; low-frequency noise (drift) is also reduced. Frequency range: 2 Hz – 1 kHz (velocity domain). Decision: If your plant does ISO 10816 velocity reporting or has a legacy velocity-based online system, HS-160; if you use a modern FFT analyzer, raw-acceleration HS-100 is more flexible.

Q: When is the HS-104 low-power accelerometer used?

Standard IEPE bias current is around 4 mA — a disadvantage for applications with critical battery life. HS-104 with ≤2 mA typical current draw halves consumption. Typical use cases: 1. Wireless sensor nodes (IoT, Industry 4.0) 2. Battery-powered monitoring devices (portable data collectors + sensor kits) 3. OEM integrated products — custom test equipment, machine-builder integrated vibration modules 4. Remote stations — solar-powered cabinets, limited power budgets For standard industrial installations (fixed cable, PLC-supplied), HS-104 isn't needed; HS-100 remains more economical.

Question 1

What is the fundamental difference between Hansford AC accelerometers and the HS-420 family 4-20 mA transmitters?

Accepted Answer

AC accelerometers (HS-100, HS-150, HS-173, etc.) output the raw vibration signal in mV/g; this signal is fed to a vibration analyzer or FFT spectrum analyzer for frequency-based fault diagnostics (bearing faults, gear wear, cavitation, imbalance, misalignment). HS-420 4-20 mA transmitters process the signal inside the sensor and send the RMS value to PLC/DCS/SCADA for trend monitoring (alarm/shutdown). Decision: AC accelerometers for spectrum analysis and advanced predictive maintenance; 4-20 mA transmitters for PLC trend monitoring only. Modern CBM programs use both layers together.

Question 2

What is the difference between compression and shear element accelerometers?

Accepted Answer

In compression sensors (HS-100, HS-105, HS-107) the PZT crystal works under compressive stress — simple, economical, wide frequency range; but more sensitive to base-strain and thermal transients. In shear sensors (HS-104, HS-150, HS-170, HS-180, HS-172, HS-173) the PZT crystal works under shear stress — significantly less sensitive to thermal shock, base strain and mounting surface flexure; premium technology. Decision: compression (HS-100) for standard industrial environments and wide frequency range; shear (HS-150/170) for thermal fluctuation, base-strain or high-frequency bearing/gear monitoring.

Question 3

What is the difference between IEPE/ICP and Line Drive (HS-107) sensors?

Accepted Answer

Most modern AC accelerometers use the IEPE (Integrated Electronics PiezoElectric) standard — constant current drive (typically 2-4 mA), 2-wire cable carrying both power and signal. ICP is PCB's trademarked name for IEPE. HS-107 uses Line Drive (Constant Voltage) — 24 Vdc CV drive, an older but still-used standard. Choose Line Drive (HS-107) when compatibility with legacy Bently Nevada, Vibrometer, Schenck, CSI, or SKF online systems is required. For new installations, choose modern IEPE series (HS-100, HS-150, HS-170, etc.).

Question 4

Which sensitivity (10 / 30 / 50 / 100 / 250 / 500 mV/g) should I choose?

Accepted Answer

Sensitivity and range are inversely related; choose based on the vibration level you'll measure.
10 mV/g (±800 g): high shock, foundry, crushers, hammer mills
30 mV/g (±250 g): heavy industrial medium-high vibration
50 mV/g (±160 g): large centrifuges, turbines (medium level)
100 mV/g (±80 g): STANDARD industrial application — motors, pumps, fans, compressors, gearboxes
250 mV/g (±32 g): precision monitoring, low-level vibration, precision bearings
500 mV/g (±16 g): laboratory measurement, high-accuracy resolution, very low-vibration equipment
Most applications are solved with 100 mV/g. In datasheets, resonance frequency also changes with sensitivity (higher sensitivity = lower resonance).

Question 5

How do I choose between Top Exit and Side Exit variants?

Accepted Answer

Top Exit (HS-100, HS-150, HS-170 standard): Cable or connector exits from the top of the sensor. Standard for installations with adequate top clearance. Supports both Female (UNF) and Male (UNF, M6, M8, M10) mounting threads.
Side Exit (HS-100S, HS-150S, HS-170S, HS-180S, HS-172, HS-173, etc.): Cable/connector exits 90° from the side. Ideal for tight spaces such as motor bearing housings, fan rotor undersides, gearbox sidewalls. Supports Male mounting threads only (02, 06, 08).
Decision: Adequate top clearance? Top Exit. Roof/cover close? Side Exit.

Question 6

When is the HS-173 Triaxial sensor required? Is single-axis enough?

Accepted Answer

For standard single-direction equipment (pumps, fans, motors), single-axis sensors (HS-100, HS-150) suffice. HS-173 Triaxial is critical in:
1. Complex machinery — gearboxes, generators, turbine blades, kiln fans, helicopter rotors (different fault signatures per axis).
2. Root-cause analysis — knowing which axis carries the imbalance accelerates maintenance decisions.
3. New installations / comprehensive CBM — on greenfield installations, a triaxial dataset forms the foundation for future spectrum interpretation.
Cost: Instead of 3 separate single-axis HS-100 + 3 cables + 3 PLC channels, use one HS-173 + 1 cable (8-pin M12) — installation time cut to ⅓, single mount point. Total cost of ownership favors triaxial for complex machinery.

Question 7

What is HS-172 Biaxial (2-axis) used for? Advantage over triaxial?

Accepted Answer

HS-172 measures only X and Y axes (no Z). Suitable when monitoring radial + tangential vibration of a rotating shaft — particularly when distinguishing imbalance (X) from misalignment (Y). Advantage: ~30% lower cost than HS-173 triaxial; 4-pin M12 connector (not 8-pin) for simpler cabling. Decision: Axial (Z) vibration is unimportant or monitored by another sensor → HS-172; full 3D vibration profile needed → HS-173. Typical use: motor, pump, small compressor radial monitoring.

Question 8

When should I choose the HS-105 high-temperature model?

Accepted Answer

Standard AC accelerometers (HS-100, HS-150, HS-170) operate between -55°C and +140°C. If the surface temperature where the sensor is mounted continuously exceeds +140°C, the HS-105 High Temperature should be used. HS-105 is designed with a special PZT composition for continuous operation up to +250°C.
Typical applications: cement kiln fans, dryers, foundries, kiln motors, steam systems, petrochemical high-temp reactors.
Practical check: the cable must also withstand high temperature — Silicon cable (code 07) or FEP (30C) recommended; PUR (01) is inadequate above +90°C.

Question 9

What does the HS-160 integrated-integrator velocity output do?

Accepted Answer

HS-100 and standard AC accelerometers output raw acceleration (g) signal; converting it to velocity (mm/s) requires mathematical integration inside the vibration analyzer. HS-160 has an integrated analog integrator inside the sensor — its AC output is directly velocity (mm/s or in/s). Advantage: no extra integration step in online systems doing ISO 10816 velocity-based monitoring or in portable analyzers; low-frequency noise (drift) is also reduced. Frequency range: 2 Hz – 1 kHz (velocity domain). Decision: If your plant does ISO 10816 velocity reporting or has a legacy velocity-based online system, HS-160; if you use a modern FFT analyzer, raw-acceleration HS-100 is more flexible.

Question 10

When is the HS-104 low-power accelerometer used?

Accepted Answer

Standard IEPE bias current is around 4 mA — a disadvantage for applications with critical battery life. HS-104 with ≤2 mA typical current draw halves consumption. Typical use cases:
1. Wireless sensor nodes (IoT, Industry 4.0)
2. Battery-powered monitoring devices (portable data collectors + sensor kits)
3. OEM integrated products — custom test equipment, machine-builder integrated vibration modules
4. Remote stations — solar-powered cabinets, limited power budgets
For standard industrial installations (fixed cable, PLC-supplied), HS-104 isn't needed; HS-100 remains more economical.

Question 11

How do I select an AC accelerometer for ATEX hazardous areas?

Accepted Answer

In the AC accelerometer family, ATEX options are indicated by "I" / "IS" / "IT" / "tb" suffixes in the model name:

Gas hazardous (Zone 0/1/2) — Ex ia (Intrinsically Safe): HS-100I, HS-104I, HS-105I, HS-107I, HS-150I, HS-170I, HS-173I — low-energy circuit + Hansford HS-IJE junction enclosure + HS-AA022 IS barrier.

Side Exit + Ex ia: HS-100IS, HS-150IS, HS-170IS — tight space + IS barrier.

Dust hazardous (Zone 21/22) — ExTb (Dust Ex): HS-150tb — flour, sugar, cement, coal dust environments.

Combined (IS + Temperature): HS-100IT, HS-150IT, HS-150IST, HS-173IR — Ex ia + 10 mV/°C or Pt100 temperature output.

Selection depends on plant ATEX certification protocol; IMB Electric engineering team offers free ATEX compliance assessment.

About the AC Accelerometers series

01What is the fundamental difference between Hansford AC accelerometers and the HS-420 family 4-20 mA transmitters?

02What is the difference between compression and shear element accelerometers?

03What is the difference between IEPE/ICP and Line Drive (HS-107) sensors?

04Which sensitivity (10 / 30 / 50 / 100 / 250 / 500 mV/g) should I choose?

05How do I choose between Top Exit and Side Exit variants?

06When is the HS-173 Triaxial sensor required? Is single-axis enough?

07What is HS-172 Biaxial (2-axis) used for? Advantage over triaxial?

08When should I choose the HS-105 high-temperature model?

09What does the HS-160 integrated-integrator velocity output do?

10When is the HS-104 low-power accelerometer used?

11How do I select an AC accelerometer for ATEX hazardous areas?