Question 1

How does a MEMS inclination sensor work? What does gravity reference mean, and what are its limits?

Accepted Answer

MEMS (Micro-Electro-Mechanical System) inclination sensors use Earth's gravity vector as reference. Inside the sensor is a small MEMS accelerometer measuring 3-axis acceleration (x, y, z). On a stationary sensor at Earth's surface, the only acceleration source is gravity (1 g = 9.81 m/s²). The sensor calculates the orientation of this gravity vector relative to its axes, yielding the inclination angle.

Operating Principle (3 steps):
1. MEMS accelerometer measures gravity components on x, y, z (ax, ay, az).
2. Tilt = atan2(ax, az) or atan2(ay, az) trigonometric calculation.
3. Result output as angular inclination (0.5-10 V, 4-20 mA, CANopen, etc.).

Single Axis vs Dual Axis:
• Single axis (±180°): Measurement around one rotating axis. Crane boom elevation, door hinge — single-degree-of-freedom applications.
• Two axes (±60°): Both azimuth and tilt — solar tracking. The ±60° limit: as the gravity vector moves away from vertical, calculation accuracy degrades; above ±60° it's mathematically unreliable.

MEMS Limit 1 — Static Measurement:
POSITILT measures accurately on stationary or slowly-moving equipment. In motion (acceleration, vibration, direction change), the MEMS accelerometer reads gravity + motion acceleration, and gravity can't be isolated alone. Result: inclination measurement drifts in dynamic environments.

Solution — POSITILT PTK (Gyro-Compensated):
PTK variants (separate page) add a 3-axis gyroscope to the MEMS. The gyro measures angular velocity — the motion component is computed in real-time and subtracted from the gravity reading. Result: accurate tilt even in motion.

MEMS Limit 2 — Temperature Sensitivity:
MEMS accelerometer linearity has a slight temperature dependence. POSITILT includes internal temperature compensation (standard on PTAM/PTDM). Outside operating range (-40°C/+85°C) linearity may drift out of tolerance.

Decision:
• Stationary or slowly moving equipment → POSITILT sufficient
• Accurate measurement during motion required → POSITILT PTK (gyro-compensated)

Question 2

How do I choose between PTAM (single-axis analog) and PTDM (dual-axis analog / redundant)?

Accepted Answer

In the POSITILT family, model names use a 3-letter code:
• PT = POSITILT
• A = Analog (output type)
• M = Mono (single channel) or D = Dual (dual channel)

Example: PTAM2 = POSITILT Analog Mono variant 2; PTDM2 = POSITILT Analog Dual variant 2.

PTAM (Single-Channel Analog) — Standard:
• Single output channel — sensor measures angle on one axis and outputs one analog signal.
• Typical use: Standard industry — crane boom angle, valve position, door hinges.
• If the sensor fails, signal is lost; PLC alarms, machine stops.
• Sufficient for most applications.

PTDM (Dual-Channel Analog / Redundant) — Functional Safety:
• Two independent output channels, two separate MEMS sensor elements.
• Both channels independently measure the same tilt.
• Required for functional safety (SIL-1, SIL-2) certification.
• If one channel fails, the other continues → fail-safe.
• PLC compares both channels; alarms if deviation exceeds 5°.
• Typical use: Crane load-chart calculation, lift platform tip detection, mobile-platform stability control, medical-device angle feedback.

Important — PTDM is NOT Dual Axis:
"Dual" here means redundant second channel, NOT two axes. If two-axis measurement is needed (azimuth + tilt), this ±60° two-axis feature already exists on PTAM models — not to be confused with PTDM.

Decision Criteria:
• Is SIL certification required?
- YES → PTDM mandatory
- NO → PTAM sufficient
• Is single-sensor failure unacceptable?
- YES → PTDM
- NO → PTAM
• Machine safety category PL d or PL e?
- YES → PTDM
• Budget limit?
- PTDM is typically 30-50% more expensive than PTAM

Which PTAM models have PTDM?
• PTAM2 → PTDM2 available
• PTAM5 → PTDM5 available
• PTAM6 → PTDM6 available
• PTAM7 → PTDM7 available
• PTAM27 → PTDM27 available
• PTAM4 (underwater): No PRDS variant (underwater single channel)
• PTM27/PTM29 (high precision): No PRDS variant

Question 3

How do I choose between single-axis ±180° and dual-axis ±60°?

Accepted Answer

Most POSITILT models support two measurement configurations — determined at order time or by physical mounting. Decision follows the motion axes of the application.

Single Axis (±180°) Configuration:
• Sensor measures angle around one rotating axis.
• Range ±180° (full half-rotation or full rotation tilt detection).
• Typical applications: Crane boom elevation (up/down), door hinges (open/closed), window panels, valve 90° open/close, hydraulic bucket angle (up/down).

Why ±180°? Single-axis measurement allows the sensor to read the full half-rotation (-180° below to +180° above). Especially useful for mobile-platform tip detection — if a platform tilts past 90°, the sensor detects it and triggers an alarm.

Dual Axis (±60°) Configuration:
• Sensor measures angles on two independent axes (e.g., X-Y plane).
• Range ±60° per axis.
• Typical applications: Solar panel tracking (azimuth + tilt), 2-axis platform stabilisation, dual-axis measurement instruments, ship pitch + roll.

Why the ±60° Limit? Two-axis math uses the gravity vector's projection on both axes. As axes move away from vertical (60°+), the projection calculation becomes ambiguous — especially near 90°, small noise produces large angle drift. This is a natural MEMS limit.

Special Case — PTAM27/PTDM27:
These models support ±180° on both axes — unique in the POSITILT family. Optimised for 3D positioning (azimuth + tilt + roll). For solar tracker high-environment platforms, robotic-arm orientation, helicopter platforms.

Decision Table:
• Single axis + full range (including tip detection) → ±180° (1 axis)
• Solar tracking + 2-axis platform (below ±60° tilt) → ±60° (2 axes)
• Wide-range 3D position (large angles on both axes) → PTAM27/PTDM27 (±180° on both axes)
• Mixed or unknown → start with default single-axis ±180°; if requirements change, switch to 2-axis version later (the same model typically supports both)

Practical Note: A sensor physically contains a two-axis MEMS — at order time, the "single-axis ±180°" or "dual-axis ±60°" configuration choice sets calibration and output format. Re-flashing the sensor is possible later, but the PLC must also be updated accordingly.

Question 4

When are the PTM27 and PTM29 high-precision models (0.001° resolution) needed? When are standard PTAM models (0.05° resolution) insufficient?

Accepted Answer

PTM27 and PTM29 are the premium-precision versions in the POSITILT family. Resolution is 0.001° — 50× more precise than standard PTAM (0.05°). Let's see the real-world impact.

Resolution Comparison:
• Standard PTAM (0.05°): 7,200 discrete positions across 360°
• High-precision PTM (0.001°): 360,000 discrete positions across 360°

Practical Difference — Examples:

1) Solar Panel Tracking:
• Tracking error with standard PTAM: 0.05° = ~8 cm offset relative to a sun 100 m away
• High-precision PTM: 0.001° = ~1.7 mm offset
• Standard sufficient — solar yield isn't affected by 0.05° error.

2) Crane Boom Angle:
• 30 m boom + 0.05° error = ~2.6 cm offset at the boom tip
• 30 m + 0.001° = 0.5 mm offset
• Standard sufficient — ~2 cm precision is acceptable for crane positioning.

3) Structural Tilt Monitoring (Bridges, Towers):
• Annual tilt change in a bridge support: 0.01-0.05°
• Standard PTAM with 0.05° resolution cannot detect or detects marginally
• PTM at 0.001° detects 5-50× more clearly → early warning, structural safety

4) Calibration Test Rigs:
• Angle-calibration lab provides 0.01° reference
• Tested sensor's accuracy must be measured
• PTM (0.001°) is used as a calibration reference → comparison with a 10× more precise test device

5) Precision Engineering Equipment:
• Optical telescope tracker, laser alignment, precision CMM (Coordinate Measuring Machine)
• These applications operate below 0.001° angular accuracy
• PTM mandatory

Decision Rule:
• Error tolerance above 0.5° → standard PTAM (most economical)
• Error tolerance 0.05°-0.5° → standard PTAM sufficient
• Error tolerance 0.01°-0.05° → PTM needed
• Error tolerance 0.001°-0.01° → PTM mandatory
• Error tolerance below 0.001° → POSITILT limit exceeded; consider optical angle sensors

Cost Impact:
PTM models are typically 50-100% more expensive than standard PTAM. This premium is justified in structural safety or precision engineering, but unnecessary in standard industrial applications.

PTM27 vs PTM29 Difference:
• PTM27: Plastic housing, IP67 — economical high-precision option
• PTM29: 316L stainless, up to IP69 — outdoor + high-precision combo
• Same 0.001° resolution on both; only environmental durability differs.

Question 5

When is PTAM4 (underwater, IP68, 10 bar) mandatory? When are standard POSITILT models insufficient?

Accepted Answer

PTAM4 is the POSITILT family's specialised model for pressurised underwater applications. Standard PTAM5/6/7 (IP67/IP69) work well in oily or wash-down environments but aren't designed for continuous underwater operation.

PTAM4 Specialised Features:

1) IP68 + 10 Bar Pressure Resistance:
• 10 bar = ~100 m water-column depth pressure.
• Certified for continuous underwater (permanent immersion) operation.
• Standard IP67 = 30 minutes at 1 m depth (short-term impulse water); not enough for continuous submersion.
• Standard IP69 = high-pressure hot-water jet (wash-down standard) — not designed for underwater operation.
• PTAM4 combines both + 10 bar pressure resistance.

2) Water-Proof Cable Seal:
• Cable entry at the sensor head is specifically sealed.
• Standard cable glands provide IP67 but may leak under continuous immersion over time.
• PTAM4 sealed cable entry guarantees permanent underwater operation.

3) Connectorless Cable Output:
• Standard POSITILT offers M12 connector option.
• PTAM4 only cable output — connectors are a risk point for underwater applications (leak potential).
• Direct cable termination provides maximum reliability.

4) 316L Stainless Steel Housing:
• 316L stainless steel (AISI 316L) for corrosion resistance — sea water, chlorine, alkali chemical resistance.
• Same material as standard stainless models, but hermetic sealing is optimised for underwater.

Typical PTAM4 Applications:
• Subsea crane boom angle monitoring — ship loading/unloading cranes, subsea operative cranes
• Underwater platform tilt control — coastal structures, offshore platforms
• Floating/submerged pipeline position — subsea cable-laying vessels
• Pressurised liquid tank tilt monitoring — chemical plants, pressurised water reservoirs
• Mining shaft (vertical well) tilt measurement — continuous moisture + pressure exposure
• Food-processing high-pressure cleaning — facilities with pressure above wash-down standards

Alternative Thinking:
Could POSICHRON PCST27 (15 bar magnetostrictive) replace PTAM4? NO — PCST27 is a linear position sensor (integrated inside hydraulic cylinders); PTAM4 is an inclination sensor (angular measurement). Different categories, not interchangeable.

Decision Table:
• Dry/oily industry + non-wash-down → PTAM2/PTAM5/PTAM6 (IP67-IP69)
• Wash-down high-pressure cleaning → PTAM5 IP68 option
• Outdoor continuous rain + occasional water splash → PTAM7 (IP67/IP69)
• Continuous underwater + 100m depth + subsea → PTAM4 (only option)
• 100m+ depth / 15+ bar pressure → POSITILT limit exceeded, ASM custom order required

Documentation Importance:
For subsea installations, PTAM4 certification + facility maritime approvals (Lloyd's, DNV-GL) are required. IMB Electric engineering team provides full documentation packages for subsea projects in Türkiye and the region.

Question 6

What's the decision between POSITILT (static) and POSITILT PTK (gyro-compensated)?

Accepted Answer

Decision rule: is the equipment in motion while measuring?

Choose POSITILT (Static MEMS) when:
• Equipment is stationary or slowly moving during measurement.
• Sensor provides correct value after motion ends (1-2 second "settle time").
• Typical use:
- Crane boom load calculation while at rest
- Solar panel tracking position check when stationary
- Structural tilt monitoring (tower, bridge — very slow change)
- Fixed-machine calibration
- Automatic door 50%-open position check
- Hydraulic bucket angle (post-emptying measurement)
• Budget advantage: POSITILT is 30-50% more economical than POSITILT PTK.

Choose POSITILT PTK (Gyro-Compensated) when:
• Equipment continuously in motion during measurement — accurate readings needed without stopping, during swing, during acceleration.
• MEMS gravity + motion mixing causes drift — gyro removes the motion component in real time.
• Typical use:
- Crane boom under load continuous angle measurement (swinging load)
- Solar tracker during active motion precision positioning
- Mobile excavator arm in motion angle feedback
- Ship platform continuous pitch+roll measurement (wave effects)
- Automotive rollover detection (dynamic manoeuvre)
- Robotic arm fast motion orientation tracking

Technology Difference:
POSITILT measures gravity direction via MEMS accelerometer. Under motion, acceleration + gravity sum is measured, and the true gravity direction is lost.

POSITILT PTK adds a 3-axis MEMS gyroscope. The gyro measures angular velocity — degrees per second (e.g., "sensor rotating Y-axis at 50°/s"). PTK's internal algorithm uses a Kalman filter or complementary filter to fuse gravity reference + gyro data → accurate tilt during motion.

Performance Difference:
• Static: POSITILT 0.05° accuracy, PTK same.
• Slow motion (1°/s): POSITILT still accurate, PTK same.
• Medium motion (10°/s): POSITILT drifts 1-2°, PTK accurate.
• Fast motion (50°/s): POSITILT drifts 5-10°, PTK accurate.
• Vibration (50 Hz): POSITILT reading visibly noisy on oscilloscope; PTK stays clean.

Comparison Table:

| Feature | POSITILT | POSITILT PTK |
|---|---|---|
| Sensor tech | MEMS accelerometer | MEMS accel + Gyro |
| Static accuracy | 0.5° | 0.5° |
| Dynamic accuracy (50°/s) | 5-10° error | 0.5° (same as static) |
| Vibration immunity | Low | High |
| Cost | Reference | 30-50% more |
| Typical use | Static or slow | Continuous dynamic |

Hybrid Approach:
Some systems combine both:
• POSITILT at fixed measurement points (economical)
• POSITILT PTK on moving equipment
• PLC receives data from both, monitors full system state

Decision: If the equipment's motion profile is unclear, IMB Electric engineering team performs field analysis — measuring vibration, speed profile, motion frequency — and recommends the right choice.

Question 7

What is the tare function? How does it simplify POSITILT field installation?

Accepted Answer

The tare function is one of POSITILT's (and POSIHALL's) most useful features. It lets users set the sensor's "zero" position wherever they want during field installation.

Standard Inclination Sensor Problem:
Inclination sensors use gravity reference — they're factory-calibrated as "gravity direction = sensor Z axis". This means the sensor reads 0° when physically mounted vertically. In field installation:

1. Sensor mounts on a crane boom.
2. Boom is assumed horizontal → sensor should read 0°.
3. But if the sensor isn't physically perfectly vertical to the boom (e.g., resting on a bracket tilted 5°), it reads 5°.
4. Define a software offset on the PLC (e.g., "true 0 = sensor value − 5°"). Complex, error-prone.

Tare Function Solution:
On POSITILT, a physical button or programming command says "current position = zero". The sensor stores the current angle as the new zero. All future readings reference this new zero.

Use Steps:
1. Sensor + equipment mounted (no matter how non-perfect the bracket).
2. Equipment set to the "zero-accepted" position (e.g., crane boom horizontal, solar panel facing horizon).
3. Tare command sent to POSITILT (via M12 connector pin or ASM programming software).
4. Sensor stores the current angle as zero.
5. PLC now measures from 0° — no software offset needed.

Advantages:
• Faster field installation: PLC programmer doesn't compute offsets.
• Fewer errors: No software-offset miscalculation, no wrong-position reporting risk.
• Easy service maintenance: After sensor replacement, re-tare for field calibration.
• Multi-installation: Same PLC code transfers to different sites without offset changes.
• Bracket flexibility: Even if the bracket isn't 100% straight, tare corrects.

Typical Scenario — Crane Boom Angle:
1. POSITILT mounted on crane boom. Boom is designed to be horizontal.
2. Sensor mounted at maybe 3° tilt (bracket tolerance).
3. Operator places boom in horizontal position (visually).
4. Presses tare button → sensor takes "boom horizontal = 0°" reference.
5. As boom rises, +value; as it lowers, -value.
6. PLC software simple: positive = elevation, negative = depression.

Tare Command Methods:
1. Physical button: On some models, small button on the side — hold pressed, LED blinks, release when tare done.
2. M12 connector pin: Apply 24V to a specific pin to trigger tare (persistent digital signal).
3. ASM programming software: Command from PC via USB.
4. CANopen command: Remote tare over the bus (PLC auto-calibration).

Which POSITILT Models Have Tare?
The tare function is available on all PTAM and PTDM models. Also on PTM (high-precision) models. PTAM4 (underwater) also supports it — but the tare command is applied before installation (not underwater).

Question 8

What are the POSITILT warranty, calibration, and IMB Electric regional support conditions?

Accepted Answer

Warranty: ASM Sensor offers a 2-year manufacturer warranty on all POSITILT models. Out-of-warranty cases:
• Mechanical impact damaging housing
• Excessive vibration or shock (outside datasheet limits)
• Use outside datasheet limits (temperature, IP, magnetic interference)
• Unauthorised opening or repair
• Pressure above 10 bar on the PTAM4 (underwater) model
• Continuous use in motion (POSITILT is designed for static — if continuous motion is needed, PTK is required)

Calibration: POSITILT is MEMS-based — no mechanical wear. Calibration intervals are long. Typically 5-10 years. For field verification:
• Tare the sensor to zero.
• Tilt to known angles (e.g., 30°, 60°, 90°).
• Sensor value must remain within ±0.5° (datasheet linearity).
• ±0.05° expected on PTM models.
• IMB Electric provides accredited calibration services in Türkiye (TÜRKAK scope).

MEMS Aging: MEMS accelerometers drift very slowly over years — typically 0.01°/year. After 10 years of use, max 0.1° loss. Acceptable in most applications, but periodic calibration is recommended in precision applications (PTM models).

Sensor Replacement: POSITILT electronics are contactless — no wear. Typical failure modes are external impact (housing damage) or excessive magnetic interference (POSITILT isn't immune to magnetic fields — mounting near large transformers isn't recommended).

PTAM4 Underwater Special Maintenance: For continuously submerged PTAM4 use, annual external inspection is recommended — cable-entry leak signs, housing corrosion check. For maritime-certified facilities, a maintenance plan compliant with Lloyd's or DNV-GL requirements is offered by IMB Electric engineering.

IMB Electric Regional Support:
IMB Electric is listed for Türkiye on ASM Sensor's official global distribution network, with authorisation extending to Türkiye + the Middle East + North Africa + Western Asia.

Regional services:
• Stock delivery (İstanbul İkitelli OSB)
• Fast quotation (24-48 hours)
• Accredited calibration and repair (TÜRKAK scope)
• Application-based engineering support — POSITILT vs PTK selection, PTAM vs PTDM redundant analysis, tare programming, underwater-installation documentation
• Local management of warranty processes
• Turkish + English + Arabic (for the Middle East) technical documentation
• Field training (on request) — tare function usage, ±180°/±60° configuration

Contact: info@imbelectric.com · +90 212 544 59 59 · imbelectric.com

About the POSITILT® — MEMS Inclination Sensors series

01How does a MEMS inclination sensor work? What does gravity reference mean, and what are its limits?

02How do I choose between PTAM (single-axis analog) and PTDM (dual-axis analog / redundant)?

03How do I choose between single-axis ±180° and dual-axis ±60°?

04When are the PTM27 and PTM29 high-precision models (0.001° resolution) needed? When are standard PTAM models (0.05° resolution) insufficient?

05When is PTAM4 (underwater, IP68, 10 bar) mandatory? When are standard POSITILT models insufficient?

06What's the decision between POSITILT (static) and POSITILT PTK (gyro-compensated)?

07What is the tare function? How does it simplify POSITILT field installation?

08What are the POSITILT warranty, calibration, and IMB Electric regional support conditions?