IFM LDL100 Conductivity Sensor

Full Model Name: LDL100 COND CONDUCTIVITY HYG G1/2

IFM hygienic two-electrode conductivity sensor with integrated transmitter (electrode + signal processing unit). No separate transmitter required. Supports IO-Link plus 4~20 mA analogue output. Widely used for CIP cleaning and phase interface detection in food & الصناعات الدوائية.

✅ Core Measurement Specifications

Conductivity range: 100 ~ 15000 µS/cm, دقة 1 µS/cm

Temperature measurement: -25 ~ +150 درجه مئوية, تعويض درجة الحرارة المدمج

Conductivity accuracy: ±25 µS/cm within 10% of full scale; دقة درجة الحرارة: ＜±0.5 K at 20~50 ℃, ＜±1.5 K across full range

وقت الاستجابة: <2 ق (T09)

انحراف درجة الحرارة: 0.2 %/K MW ±25 µS/cm

⚡ Electrical Parameters

إمداد: DC 18~30 V, حماية قطبية عكسية

الإخراج: 4~20 mA analogue (selectable for conductivity or temperature) + رابط الإدخال والإخراج

الأعلى. load for analogue output: 500 أوه

Power-on delay: 2 ق

موصل: م12

فئة الحماية: IP69K (suitable for hygienic high-pressure washdown)

🛠 Mechanical & Wetted Materials

Process thread: G1/2 external tapered sealing thread

Wetted materials: 316L الفولاذ المقاوم للصدأ (1.4404), نظرة خاطفة; seal FKM; housing PEI

Wetted surface roughness: Ra ≤0.8 μm (hygienic finish)

وزن: 270.5 ز

Installation note: ال الاستشعار السكن المعدني + metal pipeline serve as the second electrode by principle. Direct installation on pure plastic pipe is strictly prohibited. Metal adapter sleeve must be fitted for plastic pipelines, otherwise measurement fails.

🧪 Operating Principle

Two-electrode conductivity method: The metal tip of the sensor acts as electrode 1. The sensor housing and metal pipeline together form electrode 2. Voltage is applied between electrodes, and medium current is measured to calculate conductivity.

مميزة: No fixed cell constant. Readings are affected by pipe inner diameter. CGA calibration gain must be configured after installation. CGA values vary with pipe size (1.5″ ≈96% / 2″≈97% / 3″≈100%).

🎯 Typical Application Scenarios

1. CIP cleaning in food, beverage and pharmaceutical industries: distinguish clean water, alkaline and acid liquid, identify phase transition and automatically determine cleaning endpoint
2. Hygienic pipeline phase separation and tank media switch detection
3. Monitoring of high-electrolyte media (Not suitable for low-conductivity ultra-pure water. Lower limit 100 µS/cm. Use LDL101 for ultra-pure water)

⚠️ Key Limitations & Model Selection Comparison

1. Lower limit 100 µS/cm, cannot measure low-conductivity purified water; select LDL101 for purified / ultra-pure water
2. Metal pipeline or metal liner required; plastic pipe not recommended
3. Measurement is pipe-diameter dependent; on-site CGA calibration is mandatory
4. LDL100: two-electrode hygienic type, G1/2, 100~15000 µS/cm; LDL2xx: inductive type (non-contact, anti-fouling)

📌 Accessories

Weld bosses, Varivent hygienic adapters E43306 / E43307 / E43310

Metal adapter E43313 (for plastic pipeline retrofit)

🧯 Troubleshooting

1. Drifting / inaccurate readings: Verify metal pipeline; confirm CGA parameter matches pipe diameter; check electrode fouling after CIP
2. No signal: Check M12 pin assignment, DC18~30V supply and polarity; verify IO-Link master version
3. Abnormal temperature: Temperature probe damage or medium temperature exceeding 150 ℃ upper limit

IFM LDL100 Field Application Cases

تحديد المواقع الأساسية: Hygienic two-electrode sensor, mainly for phase interface detection (not for ultra-pure water purity measurement). Range 100~15000 µS/cm, metal pipe installation. رابط الإدخال والإخراج + 4~20mA dual output, built-in temperature measurement, IP69K withstands high-temperature CIP flushing.

قضية 1: Complete CIP System for Food Industry (Official IFM Reference Case)

صناعة: Dairy / beverage system integrator

عملية: In-place pipeline CIP cleaning (Product → Water pre-rinse → Alkaline cleaning → Rinse → Acid cleaning → Final clean water)

غاية: Phase transition detection, replacing fixed timer control

LDL100 detects sudden conductivity changes in real time: milk (high conductivity) → clean water (low conductivity) → alkaline solution (very high conductivity) to automatically determine phase switching points.

فوائد: Replace fixed timing; move to next phase only when conductivity meets rinse criteria. Reduces water, chemical and heat consumption, shortens CIP cycle, prevents residual chemical contamination of finished products. IO-Link uploads real-time conductivity and temperature for HMI monitoring and diagnostic.

النقطة الرئيسية: Install on stainless steel hygienic pipeline, configure CGA diameter calibration factor during commissioning.

قضية 2: Phase Separation & Product Recovery in Juice / Beverage Lines

صناعة: Fruit juice, concentrated beverage, plant-based drink

عملية: Batch pipeline switching, separating product and rinse water

غاية: Detect interface between product and water to reduce product loss

Significant conductivity difference between different media. LDL100 captures phase interface signal to trigger valve switching, fully divert product stream to storage tank and avoid discharging large amount of product to waste water; also verify rinse completeness.

المزايا: Hygienic Ra≤0.8 μm, withstand short-time CIP temperature up to 150 درجه مئوية, no separate transmitter required to save cabinet space.

القيد: Only for metal pipelines; metal liner required for plastic pipe.

قضية 3: CIP/SIP Endpoint Verification for Pharmaceutical Preparation Lines

صناعة: Biopharma, oral dosage (non ultra-pure water loop)

عملية: CIP cleaning for preparation pipelines, rinse validation for acid/alkaline detergent

غاية: Confirm complete removal of cleaning chemicals for GMP cleaning validation

LDL100 monitors rinse water conductivity. When conductivity drops below threshold, cleaning is deemed qualified. Conductivity and temperature history can be logged for GMP audit trail.

ملحوظة: Not for purified / ultra-pure water loop (<100 µS/cm), use LDL101 instead.

قضية 4: Salinity & Ion Monitoring for Cooling / Process Circulating Water in Food Plants

صناعة: Food plant utility system

عملية: Stainless steel cooling water circulation system

غاية: Monitor ion / salt concentration of circulating water and provide early warning for scaling and corrosion risk

Rising ion concentration of circulating water increases conductivity. LDL100 outputs signal to trigger blowdown / water makeup, while acquiring medium temperature for compensation.

Suitable for medium-conductivity circulating water; not for ultra-pure water.

قضية 5: Pipeline Media Switching for Sauce & Cheese Production

صناعة: Dairy, sauce (ketchup, salad dressing)

عملية: Batch production, switching among product, rinse water and cleaning liquid inside pipeline

غاية: Prevent cross-contamination between batches by automatic phase separation

Sauce conductivity is much higher than clean water. The sensor detects the interface and switches flow direction automatically to reduce cross-contamination between different products. It also monitors concentration range of acid/alkaline detergent during CIP.

In cheese factory CIP projects, LDL series verifies complete detergent flushing to guarantee milk product safety.

قضية 6: Industrial Parts Cleaning Line (Hygienic Metal Cleaning Loop)

صناعة: Precision food machinery / pharmaceutical equipment parts cleaning

عملية: Metal workpiece spray cleaning, alkaline wash → rinse

غاية: Monitor outlet pipeline of cleaning tank to verify full alkaline rinse-out

High conductivity of waste cleaning liquid; conductivity drops after rinsing with clean water. LDL100 judges rinse endpoint. IO-Link supports remote parameter reading and fouling diagnosis.

❌ السيناريوهات غير المناسبة (Model Selection Pitfalls)

1. Ultra-pure water / purified water (conductivity ＜100 µS/cm, below measuring range; select LDL101)
2. All-plastic pipeline (no metal as second electrode, measurement impossible; metal sleeve required)
3. Heavy fouling / abrasive media (fouling changes electrode cell constant; LDL2xx inductive non-contact type recommended)

✅ General Commissioning Notes for All Cases

1. تثبيت: Prefer rising pipe to maintain full pipe without air bubbles; mount at 45° for horizontal pipe
2. CGA gain calibration must be performed and matched with pipe inner diameter
3. Temperature compensation parameter T.cmp set according to ion characteristics of medium
4. IO-Link accesses conductivity, medium temperature and sensor diagnostic data simultaneously

IFM LDL100 CIP PLC Control Logic with Phase Switch Threshold Examples

طلب: CIP for dairy / beverage hygienic pipeline. LDL100 sensor, الإخراج: 4~20mA or IO-Link reading of conductivity (µS/cm) + medium temperature. PLC switches CIP sequence automatically based on conductivity threshold instead of fixed timer.

Precondition: LDL100 CGA diameter calibration completed, pipeline full of liquid without air bubbles.

1. Reference Thresholds (Field fine-tuning required based on actual medium)

ملاحظات:

Thresholds are for engineering reference only. Values vary with medium, concentration and temperature, must be calibrated on site.

Add delay filtering (5~10s stable judgement) to avoid false valve switching caused by instantaneous conductivity spikes from air bubbles.

2. PLC Logic Framework (Ladder Diagram Concept)
3. Signal Acquisition

IO-Link readout: LDL100 → Conductivity value (µS/cm), medium temperature, sensor status bit (عيب / ok)

4~20mA mode: AI module sampling, convert to conductivity; read temperature channel separately

2. Fault Interlock

Sensor fault bit =1: suspend automatic CIP sequence, trigger HMI alarm, disable automatic phase transition

Medium temperature＞150℃: إنذار درجة الحرارة الزائدة (LDL100 upper limit 150℃)

3. Process State Machine

State machine mode with sequential forward transition only, no skip allowed.

Transition condition for each stage: Conductivity threshold met + stable delay + sensor healthy

4. HMI Functions

Real-time trend: الموصلية & temperature history curve for GMP audit trail

Parameter screen: Adjustable conductivity thresholds and delay time for each stage

Alarms: Conductivity out of range, كسر سلك الاستشعار, على درجة الحرارة, CIP timeout

5. Safety Backup

Max timer for each stage. على سبيل المثال, max alkaline cleaning duration 30 دقيقة. Force alarm and safety drain upon timeout regardless of conductivity value, preventing process lockup.

3. Typical Interlock Logic Example (Stage Transition)

مثال: Pre-rinse → Alkaline cleaning

لو (Conductivity ≤1500 µS/cm) AND (Sensor_OK) AND (Stable for 10s) THEN

Close pre-rinse inlet valve

Open alkaline supply valve

Set CIP state to 【Alkaline Cleaning Stage】

END_IF

4. LDL100-Specific Commissioning Notes
5. Re-run CGA gain calibration every time pipe inner diameter changes, otherwise reading deviation causes wrong phase switch
6. Air bubbles cause violent conductivity fluctuation. Install sensor at full-pipe location, avoid high points with air pockets
7. Keep temperature compensation enabled for high-temperature CIP/SIP; LDL100 performs internal conductivity compensation
8. Electrode fouling leads to reading drift. Program can add periodic maintenance reminder (triggered by accumulated CIP cycles)
9. Optional Extended Logic

Log peak / minimum conductivity, duration of each stage into audit trail database (GMP pharmaceutical projects)

Automatic maintenance alert: Trigger probe cleaning prompt when baseline conductivity drifts beyond set percentage under identical medium