Question 1

How do I choose between POSIROT AWS (potentiometric) and POSIROT Magnetic (PRAS/PRDS)?

Accepted Answer

Decision rule: cycle count, accuracy need, digital output requirement, and budget.

Choose POSIROT AWS (Potentiometric) when:
• Budget is critical — 40-50% cheaper than POSIROT Magnetic.
• Low-to-medium cycle application — a few movements per hour, below 100-500 cycles/day.
• Simple analog output sufficient — potentiometer R/W resistance, 0-10 V, or 4-20 mA.
• Typical use: Industrial measurement instruments, economical OEM angle feedback, manual setpoint potentiometers, educational/test rigs, tractor/loader arms (low cycle).

Choose POSIROT Magnetic (PRAS/PRDS) when:
• High cycle application — continuous rotation, millions of cycles.
• Digital output required — Incremental, SSI, CANopen, J1939.
• Higher accuracy required — wait, ±0.3% f.s. (Magnetic) vs ±0.10-0.20% f.s. (AWS — actually AWS is more accurate!).
• Contactless critical — wear-free life.
• ATEX hazardous areas — only Magnetic EX models are certified.
• Outdoor robust — magnetic technology offers broader environmental durability.

Important — Accuracy Surprise:
AWS is actually more accurate — ±0.10% f.s. (for 345°/180°). POSIROT Magnetic is ±0.3% f.s.! This accuracy difference comes from the potentiometer's continuous analog signal. Magnetic operates with digital sampling.

In practice: AWS is the right choice in high-accuracy + low-cycle scenarios. Choose Magnetic (PRAS/PRDS) for high cycle or outdoor robustness.

Quick decision:
• Measurement instrument, setpoint potentiometer, educational rig: AWS
• Crane boom, mobile machinery joint, solar tracking: POSIROT Magnetic (high cycle + outdoor)
• Low budget + standard industry: AWS
• Digital interface required (PLC SSI/CAN): POSIROT Magnetic or POSIHALL

Question 2

What's the difference between AWS1 (Servo Flange) and AWS2 (Square Flange)? Which should I choose?

Accepted Answer

AWS1 and AWS2 are completely the same sensor — all electrical and performance characteristics (measuring range, output, linearity, cycle life, housing material) are identical. The only difference is the mechanical flange type.

AWS1 — Servo Flange (Round):
• Flange shape: Round/circular
• Mounting: Circumferential 3 or 4 screws fixing to a mounting plate
• Advantage: Angle adjustment flexibility — the flange rotates; loosening the screws allows fine-tuning of the sensor's angular position. Easy zero-point calibration.
• Use: Industrial measurement instruments, lab equipment, classic OEM angle-sensor applications.

AWS2 — Square Flange (Rectangular):
• Flange shape: Square/rectangular plate
• Mounting: Standard 4-corner-hole flat plate mounting
• Advantage: Standard panel mounting — uses existing industry-standard M5/M6 screw flat mount. Easier installation, faster serial production.
• Use: Standard industrial panel mounting, in-machine integration, OEM equipment enclosures.

Decision Steps:
1. Check the existing mounting plate type:
• Round mounting hole or circumferentially screwed plate → AWS1
• Square/rectangular flat plate mounting → AWS2

2. Angle calibration needs:
• Sensor angle requires fine adjustment in field installation (lab, measurement instruments) → AWS1 (servo flange flexibility)
• Zero position is fixed, adjustments via software → AWS2 sufficient

3. Application:
• Classic measurement device, educational rig, precision reference → AWS1
• Industrial panel, in-machine, OEM serial product → AWS2

Cost: Both models are typically sold at the same price — only the flange shape differs; material + production cost is the same.

Important — No Software Difference:
The PLC can't distinguish AWS1 vs AWS2. Both provide the same output signal (e.g., 4-20 mA) and follow the same calibration curve. PLC code works with either model.

Question 3

Measuring range selection: 345° / 180° / 90° — which to choose when?

Accepted Answer

POSIROT AWS comes in three measuring ranges — selected at order time. The range defines the physical length of the potentiometer resistance strip; smaller range = more precise measurement (less angle represented within the same analog voltage range).

345° — Most Common (Standard):
• Near-full rotation measurement. Not 360° due to the potentiometer's mechanical limit (15° dead band).
• Linearity: ±0.10% f.s. → ~0.345° error across the 345° range.
• Use: Crane boom angle, valve position (full 0-360° turn), bucket angle feedback, direction control.
• Most common choice — near-full range measurement + standard accuracy.

180° — Half Turn:
• Half-turn measurement. More compact if the shaft rotates only between 0-180°.
• Linearity: ±0.10% f.s. → ~0.18° error across the 180° range (more accurate).
• Use: Oscillating motions (rocker arms), half-turn valves, angled covers, operating-table angle feedback.

90° — Quarter Turn (Most Precise):
• Quarter-turn measurement. For very narrow angular motion.
• Linearity: ±0.20% f.s. → ~0.18° error across the 90° range.
• Use: Precision valve position (90° turn), angled-plate sensors, throttle position.
• Note: Linearity 0.20% — slightly higher than the others (the potentiometer resistance strip is optimised for the 90° range, natural deviation lower).

Decision Rule:
1. Does the actual shaft motion exceed 270°?
• Yes → 345° (full rotation measurement)
• No → Go to question 2
2. Is the shaft motion below 100°?
• Yes → 90° (more precise)
• No → 180° (half turn)

Accuracy Calculation:
Linearity 0.10% f.s. translates to:
• 345° range: 0.10% × 345° = ±0.345° max error
• 180° range: 0.10% × 180° = ±0.18° max error
• 90° range: 0.20% × 90° = ±0.18° max error

So 180° and 90° ranges have similar linearity. The 345° range has 2× more error margin — acceptable in most applications.

Continuous Rotation Option:
If the shaft rotates continuously (e.g., RPM measurement), the 345° "continuous rotation" variant is ordered. The sensor reads within 345° then resets to 0 — counting is done by the PLC.

Question 4

What's the potentiometer cycle life? When is AWS insufficient in typical scenarios?

Accepted Answer

POSIROT AWS cycle life per datasheet: 100 × 10⁶ revolutions (100 million revolutions) — at 1500 RPM continuous, that's ~1,100 hours or ~140 days for a device running 8 hours/day.

But most real applications aren't 1500 RPM continuous. Let's run the numbers:

Cycle Life Formula:
Life (hours) = 100,000,000 revolutions / (RPM × 60)
Life (years, 8 hours/day) = Life (hours) / (8 × 365)

Typical Scenario Calculations:

Scenario 1 — Industrial Measurement Instrument (Low Cycle):
• Typical operation: 50 movements/day × 1 cycle = 50 cycles/day
• Annual: 50 × 365 = 18,250 cycles
• 100M cycles / 18,250 = ~5,500 years of life 😊 (effectively infinite)
• Result: AWS more than sufficient, 100% correct choice

Scenario 2 — Valve Position Monitoring (Medium-Low Cycle):
• 2 valve open/close per hour = 16/day (8 hours)
• Annual: 16 × 365 = 5,840 cycles
• 100M / 5,840 = ~17,000 years of life
• Result: AWS more than sufficient

Scenario 3 — Tractor Loader Arm (Medium Cycle):
• Operator performs 200 movements/day (bucket fill+empty)
• Annual: 200 × 200 working days = 40,000 cycles
• 100M / 40,000 = ~2,500 years of life
• Result: AWS sufficient, even for mobile-machinery outdoor use

Scenario 4 — Conveyor Drum RPM (High Cycle):
• Drum rotates continuously at 50 RPM, 16 hours/day
• Hourly 50 × 60 = 3,000 cycles/hour
• Daily 3,000 × 16 = 48,000 cycles/day
• Annual 48,000 × 250 = 12 million cycles/year
• 100M / 12M = ~8 years of life
• Result: AWS may suffice, but POSIROT Magnetic or POSIHALL is smarter for long-life applications.

Scenario 5 — Servo Motor RPM (Very High Cycle):
• Motor 3000 RPM continuous, 24 hours
• Annual: 3000 × 60 × 24 × 365 = ~1.6 billion cycles/year
• AWS life: 100M / 1.6B = ~22 days 😭
• Result: AWS UNSUITABLE. POSIROT Magnetic or POSIHALL required.

General Rule:
• Below 100 cycles/day → AWS lasts for decades, economical choice
• 100-10,000 cycles/day → AWS 5-10 years, acceptable (for limited budget)
• Above 10,000 cycles/day or continuous rotation → POSIROT Magnetic or POSIHALL required

Wiper Wear Symptoms:
When AWS cycle limit is exceeded:
• Output signal "noise" increases (micro-spikes)
• "Dead zones" form at certain angles (wiper loses contact)
• Repeatability drops (different values at the same position)

When these symptoms appear, sensor replacement is needed. Migration to magnetic-based (Magnetic/POSIHALL) solutions can be planned for the next stage.

Question 5

AWS output interface selection: R1K potentiometer, 0-10 V, 4-20 mA (2/3-wire), Programmable — which for which PLC?

Accepted Answer

POSIROT AWS supports 5 different analog output interfaces. There are NO digital outputs (SSI, CANopen, J1939) — a natural limit of potentiometer technology. Choice depends on PLC compatibility.

1) R1K — Potentiometer 1 kΩ (345° range only):
• Raw resistance output: 0Ω → 1000Ω.
• Three connections: +V, signal, GND. Signal pin is the wiper contact.
• Advantage: Simplest, cheapest. No active electronics — just a passive resistance strip.
• PLC need: Potentiometer input card or bridge circuit.
• Limit: Available only for 345° (not 180° or 90°).
• Use: Test rigs, education, simple OEM (when PLC has a dedicated input card).

2) 10V — 0-10 V Signal Conditioner:
• Internal signal conditioner converts the potentiometer resistance to 0-10 V.
• Advantage: Industry-standard analog. Supported by most PLC analog input cards.
• Limit: Voltage drop on cables longer than 100 m.
• Use: Standard factory interior, fixed installation (e.g., measurement instruments).

3) 420A — 4-20 mA, 2-wire:
• Current loop, 2-wire (signal + power on the same wire).
• Advantage: Single cable for both power and signal — simpler cabling.
• Limit: Sensor resets at each update.
• Use: Industry standard, medium-long distance (100-1000 m), simple cabling.

4) 420T — 4-20 mA, 3-wire:
• Current loop, 3-wire (power + signal on separate lines).
• Advantage: Instant updates, faster response. Default for long-distance industry.
• Use: Standard industry, long distance, noise-immune transmission.
• Most common choice for AWS.

5) PMUV / PMUI — Programmable:
• PMUV = Programmable Voltage (0-10 V range + zero/span adjustable)
• PMUI = Programmable Current (4-20 mA range + zero/span adjustable)
• Advantage: User programs zero position and range as needed (via USB with ASM PMU software).
• Example: 50°-200° portion of the 345° range mapped to 0-10 V → physically 150° range used, more precise.
• Use: Flexible calibration, multiple installations, same sensor for different applications.

Decision Table:
• Short distance + simple OEM → 10V
• Standard industry (remote PLC) → 420T (4-20 mA 3-wire) — most common
• Single-cable budget → 420A (4-20 mA 2-wire)
• Flexible field calibration → PMUV or PMUI
• Test/education + special PLC card → R1K (345° only)

Important Limit:
AWS supports only a single output channel. For SIL-2 functional safety, either two separate sensors (e.g., two AWS) or a switch to POSIROT Magnetic PRDS variant is required.

Question 6

AWS installation rules: shaft coupling, mounting torque, continuous-rotation setup — practical tips?

Accepted Answer

AWS installation is simple but four details can go wrong.

1) Shaft Coupling — Important Decision:
The AWS shaft is an independently rotating part — it doesn't connect directly to the motor shaft without coupling. Use a flexible coupling (oldham or bellows):

• Oldham coupling: Two discs sharing a middle plate. ±0.5 mm axial offset, ±1° angular deviation tolerance.
• Bellows coupling: Flexible metal bellows. ±1 mm axial, ±2° angular deviation.
• Don't use rigid coupling: Shaft eccentricity strains the AWS bearing, reducing cycle life.

2) Mounting Torque:
When fixing the AWS body to the mounting surface, tighten screws to the right torque:
• AWS1 (servo flange): 3-4 screws at 2-3 Nm. Over-tightening damages the servo-flange adjustment mechanism.
• AWS2 (square flange): 4 corner screws at 3-5 Nm. Standard panel-mounting torque.

3) Zero-Position Adjustment (AWS1):
The AWS1 servo flange feature enables field calibration:
1. Sensor mounted with screws loosened.
2. Shaft set mechanically to the "zero-accepted" position.
3. Sensor body rotated — output signal monitored on a multimeter or PLC screen.
4. When output reads 0 V (or 4 mA, for zero position), flange screws tightened.
5. Zero position is permanent.

AWS2 lacks this mechanical adjustment — zero position is set via a PLC software offset.

4) Continuous Rotation Order Detail:
Standard AWS is limited to a 345° range — doesn't measure a full 360° turn. If the shaft rotates continuously (e.g., conveyor drum RPM measurement):

• Standard AWS reads within the 345° range; after 345°, the sensor enters a 10-15° "dead zone".
• Order the "continuous rotation" variant — the sensor transitions smoothly from 345° → 0°, minimal dead zone (1-2°).
• PLC counting algorithm: counter increments by 1 every full 360°; total position = counter × 360° + AWS reading.

5) Cable Management:
The AWS shaft can rotate up to 10,000 RPM — if the cable exits the sensor body, it must be in a fixed position, not flexing with the rotating part.

If the cable must attach to the rotating part, use a slip ring — special hardware, contact IMB Electric for consulting.

6) Temperature Sensitivity:
AWS standard range is -40°C to +85°C. The potentiometer resistance strip's thermal expansion causes linearity deviation outside this range.
• In cold environments (e.g., below -20°C) the potentiometer wiper stiffens slightly in grease — a 5-10 minute warm-up may be needed.
• At high temperatures (>70°C) wiper-resistance friction increases, cycle life shortens.

In standard industrial applications, AWS operates flawlessly between 0-50°C.

Question 7

What does programmable analog (PMUV / PMUI) do? How does it simplify field calibration?

Accepted Answer

PMUV (Programmable Voltage) and PMUI (Programmable Current) are options that allow the user to program the output range and zero position of the AWS. Designed for field-installation flexibility.

Standard AWS (R1K, 10V, 420A, 420T):
• Factory-calibrated fixed output: the entire 345° range maps to 0-10 V or 4-20 mA.
• Field use only covers a portion (e.g., valve rotates 30°-120°)? The output still represents the full 345° range.
• This means resolution loss for the user — actual motion is 90° but the output signal spreads across the 345° range.

PMUV / PMUI Solution:
Via USB and the ASM PMU software, the sensor's:
• Zero position is programmed to a chosen physical angle
• Span (range) is programmed to a chosen physical angle

Example Scenario:
A hydraulic-cylinder valve shaft rotates from 30° to 120° (90° range). With standard AWS (345° → 0-10 V):
• 30° = ~0.9 V
• 75° = ~2.2 V (midpoint)
• 120° = ~3.5 V
• Output uses only 0-3.5 V range → 6.5 V wasted
• For a 14-bit PLC card: 16,384 steps / 3.5 V = need ~4,685 steps

AWS programmed with PMUV:
• Zero = 30°, Span = 90° (physical 30° → 0 V, physical 120° → 10 V)
• 30° = 0 V
• 75° = 5 V (midpoint)
• 120° = 10 V
• Output uses full 0-10 V range
• PLC resolution: 16,384 steps → spread across the full 90° → 0.0055°/step → much more precise

Advantages:
1. Faster field installation: The PLC programmer doesn't compute offsets — sensor outputs the right signal directly.
2. Higher resolution: Full output range used → all PLC analog input bits leveraged.
3. Simpler software: PLC code is clean, no scaling formula needed.
4. Multi-installation: Same AWS model assigned to different field points with separate calibrations — e.g., 5 different valves, each with a different angle range.

Limitations:
1. USB programming required: ASM PMU software + USB programming cable. Initial setup takes 5-10 minutes.
2. Field updates: Sensor must be unmounted and connected to a PC. Field engineers must carry a laptop + cable.
3. Cost: PMUV/PMUI variants are 15-20% more expensive than standard 10V or 420T.

Decision Rule:
• Field angle range is close to the full 345° (e.g., >270°) → Standard output (10V, 420T) sufficient.
• Field angle range is narrow (e.g., <180°) and accuracy is critical → PMUV/PMUI improves resolution.
• Same sensor used in multiple locations with different calibrations each → PMUV/PMUI provides flexibility.

Question 8

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

Accepted Answer

Warranty: ASM Sensor offers a 2-year manufacturer warranty on all POSIROT AWS models. Out-of-warranty cases:
• Cycle life exceeded (use beyond 100M revolutions — wiper wear depending on application)
• Excessive shaft load (radial/axial limit exceeded — specified in datasheet)
• Use of rigid coupling causing shaft-eccentricity damage
• Use outside datasheet limits (temperature, IP, RPM)
• Unauthorised opening or repair
• Liquid or chemical ingress into the unit

Calibration: POSIROT AWS is potentiometer-based — field calibration interval depends on cycle count.
• Low cycle (below 500 cycles/day): 5-10 year calibration interval.
• Medium cycle (500-5000/day): 2-3 years.
• High cycle (5000+/day): Annual checks recommended.

For field verification:
• Rotate the sensor to a known zero position.
• Measure the output, compare against the datasheet reference.
• Deviation must stay within ±0.10% f.s. (345°/180°) or ±0.20% (90°).
• If a wiper "dead zone" is detected → sensor replacement.
• IMB Electric provides accredited calibration in Türkiye (TÜRKAK scope).

Wiper Wear Indicators (Maintenance Signals):
As the AWS approaches its cycle limit, visual/audio signs appear:
• Rotating the shaft by hand reveals a slight "click" sensation
• Output shows 5-10 mV micro-spikes (visible on oscilloscope)
• Repeated tests at the same position show deviations above 0.5°

If any of these signs appear, sensor replacement is recommended — progressing wiper wear leads to total signal loss and a risk of sudden failure.

Sensor Replacement Recommendation:
If wiper wear begins in high-cycle applications, the next step may be a migration to POSIROT Magnetic or POSIHALL. The 40-50% economic advantage of AWS is offset over time by wiper-wear costs.

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 — AWS vs Magnetic decision consulting, cycle-life calculation, PMUV/PMUI programming support
• Local management of warranty processes
• Turkish + English + Arabic (for the Middle East) technical documentation
• Field training (on request) — servo-flange calibration technique, coupling selection

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

About the POSIROT® AWS — Potentiometric Angle Sensors series

01How do I choose between POSIROT AWS (potentiometric) and POSIROT Magnetic (PRAS/PRDS)?

02What's the difference between AWS1 (Servo Flange) and AWS2 (Square Flange)? Which should I choose?

03Measuring range selection: 345° / 180° / 90° — which to choose when?

04What's the potentiometer cycle life? When is AWS insufficient in typical scenarios?

05AWS output interface selection: R1K potentiometer, 0-10 V, 4-20 mA (2/3-wire), Programmable — which for which PLC?

06AWS installation rules: shaft coupling, mounting torque, continuous-rotation setup — practical tips?

07What does programmable analog (PMUV / PMUI) do? How does it simplify field calibration?

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