APG‑500C Precision Resistance (Pirani) Vacuum Transmitter

Nom et prénom: APG-500C Precision Resistance (Pirani) Vacuum Transmitter (Pirani Gauge)

Commonly known as Chengzhen vacuum transmitter gauge, equivalent to INFICON PSG500

Marque: Chengdu Zhenghua Electronic Instrument, Trademark: 【Chengzhen】

✅ Spécifications clés

Principe de mesure: Pirani (thermal conduction resistance vacuum gauge)

Plage de mesure: 5×10⁻² Pa ～ 1×10⁵ Pa (Air / N₂)

Alimentation: 13.5~30 VCC, Power consumption ≤2W, Max inrush current ＜300mA

Sortie analogique: Logarithmic voltage 1.9～10.0 VDC (0~0.5V indicates filament failure)

Interface électrique: RJ45 (8-core FCC68)

Vacuum Flange: Standard KF16 (mainstream version)

Max Pressure Withstand: ≤0.2 MPa (pression absolue)

Temps de réponse: 100 MS

Exigence de montage: Pose verticale, keep away from heat sources and vibration sources

Médias applicables: Air, N₂, O₂, CO and other inert gases only; Combustible, explosive and strongly corrosive gases are prohibited

📌 RJ45 Pin Definition

Relay Rating: DC30V / 500mA (Only APG500CC supports multi-point threshold control; standard APG-500C has no adjustable control points)

📎 Gas Correction Factor (Reading × C)

Air/N₂/O₂/CO=1.0；H₂=0.5；He=0.8；Ar=1.7；CO₂=0.9；Xe=3.0；Kr=2.4；Ne=1.4；Water vapor=0.5

🛠 Calibration Notes

1. Preheat for at least 10 min before calibration; continuous power-on is recommended to maintain thermal balance
2. ATM full-scale calibration: At atmospheric pressure, set to 1×10⁵ Pa → 10.0 VCC
3. HV zero calibration: Pump down to ≤1×10⁻² Pa, set to 1×10⁻² Pa → 1.5 VCC

📌 Matching Products & Alternatives

Matching indicator: PDM-5203, PDM-520C

Import equivalent: INFICON PSG500

Upgraded model in same series: APG-500CC (with adjustable relay threshold)

Common failure: Platinum wire contamination, platinum wire burnout (fault output 0~0.5V). Contamination damage is excluded from warranty

📋 Typical Applications

Machines de revêtement, vacuum furnaces, leak detection systems, vacuum packaging, negative pressure processes, coarse & medium vacuum monitoring for semiconductor

APG-500C (Chengzhen/Zhenghua) Liste de contrôle de dépannage

Condition préalable: Distinguish between 【gauge failure】, 【wiring/acquisition side failure】 and 【vacuum system leakage / process issue】 first; 0~0.5V output = filament failure (fil cassé / heavy contamination). This is a hard fault, and contamination damage is not covered by warranty.

Required tools: Multimeter for RJ45 pin voltage measurement, mégohmmètre, standard vacuum source, leak detector

1. Faute: Fixed output 0～0.5V (fault voltage)

Symptôme: Voltage locked at 0~0.5V, reading unchanged regardless of vacuum, indicator reports fault

Causes profondes:

1. Burned platinum thermal wire (le plus fréquent; easily damaged by repeated atmospheric shock, sudden venting or overpressure)
2. Heavy oil contamination / coating dust covering the thermal wire inside the gauge, causing thermal conduction failure
3. Broken wire inside RJ45 plug, poor contact on pin1/pin2 power supply
4. Damaged drive PCB inside gauge

Étapes de dépannage:

① Measure pin1 & pin2 with multimeter to confirm stable 13.5~30VDC supply

② Test with a confirmed good dedicated RJ45 cable

③ If power supply is normal and output remains 0~0.5V after cable replacement → sensor defective

Remède: Replace the gauge head directly. Do not disassemble and clean the thermal wire by yourself (easy to cause permanent damage and void warranty)

2. Faute: Aucune sortie du tout, no signal on meter, floating reading on PLC

Symptôme: No voltage at signal terminals, same as no connection

Causes profondes:

1. Alimentation manquante, reverse polarity, fusible grillé
2. Broken core inside RJ45 cable, bad crimp on crystal head, broken signal core pin3/pin5
3. Mismatched input impedance of acquisition terminal (required ≥10kΩ)

Étapes de dépannage:

① Measure voltage pin1-pin2, vérifier la polarité (pin1=24V+, pin2=GND)

② Power the gauge separately and measure analog output directly at pin3 & pin5 to rule out rear-end wiring/module faults

③ Confirm PLC/display meter supports high-impedance voltage input; do not use current input channel

Remède: Remplacer le câble, correct power polarity, use compatible acquisition channel

3. Faute: Inaccurate reading, large deviation, wrong value at atmosphere or high vacuum

Symptôme: Not 1E5Pa at atmospheric pressure, cannot reach expected vacuum after pumping, large deviation compared with reference gauge

Causes profondes:

1. No preheating or calibration (≥10min preheating required)
2. Gas is not air/N₂ and gas correction factor not applied (large deviation for Ar, He, H₂)
3. Slight contamination or long-term drift of thermal wire
4. Wrong mounting orientation (non-vertical installation, condensate/dust accumulates on thermal wire)
5. Leakage at KF flange, aged KF O-ring, misaligned gasket
6. Gauge inlet partially blocked by oil mist or dust

Étapes de dépannage:

① Atmosphere calibration: Vent to atmosphere, stabilize for 10 min, perform atmospheric calibration

② Pump down to ≤1×10⁻²Pa for zero calibration

③ Confirm gas type and apply correction factor

④ Check mounting posture: Pose verticale, flange downward or lateral; avoid upside-down installation which causes liquid accumulation

⑤ Isolate gauge and perform leak test for chamber leak rate

Remède: Recalibrate, adjust installation, replace sealing ring, add front oil baffle; replace sensor if heavily contaminated

4. Faute: Reading fluctuates continuously, severe drift and instability

Symptôme: Vacuum is stable but reading jumps back and forth

Causes profondes:

1. Large ripple / unstable power supply, shared power supply with high-power motors or inverters
2. Signal cable routed together with power cable, interférence électromagnétique
3. Intrinsic pressure fluctuation of system (pump pulsation, frequent valve switching, airflow disturbance)
4. Slight contamination or aging of thermal wire
5. Mauvaise mise à la terre, mixed analog signal ground and power ground

Étapes de dépannage:

① Use isolated DC power supply for independent gauge power supply

② Single-end grounding for cable shield, tenir à l'écart des câbles d'alimentation

③ Remove gauge and power on in static atmosphere; if stable at atmosphere → fault from system airflow / fuite

Remède: Add shielding, isolated power supply, optimize grounding; add damping tube on chamber

5. Faute: Permanent atmospheric reading (~10 V), reading does not drop while pumping

Symptôme: Pump keeps running, gauge stays at atmospheric pressure reading

Causes profondes:

1. Severe leakage at KF flange, missing or damaged O-ring
2. Isolation valve before gauge closed, gauge separated from chamber
3. Gauge inlet fully blocked by solid deposit, gas cannot enter gauge cavity
4. Défaut du circuit interne, output locked at full scale

Étapes de dépannage:

① Close gauge isolation valve, test gauge under vacuum separately to distinguish gauge fault or system leakage

② Visual check KF O-ring and clamp compression

③ Disassemble flange and check inlet for coating material / dust blockage

Remède: Leak detection, open valve, clean inlet; replace sensor if blocked and thermal wire contaminated

6. Faute: Abnormal relay setpoint (APG-500CC relay version only)

Symptôme: Relay does not trigger / false trigger at target vacuum

Causes profondes:

1. Wrong threshold calibration procedure (incorrect timing of setting button)
2. Relay contact overloaded (max DC30V/500mA; cannot drive high-power load directly)
3. Oxidized or welded contacts
4. Signal drift, mismatch between actual vacuum and gauge output voltage

Étapes de dépannage:

① Relearn threshold following manual (hold setting pin, reach target vacuum then release)

② Test contact continuity with multimeter under no-load condition

③ Add intermediate relay for load isolation

Remède: Recalibrate; replace whole transmitter if contacts damaged

7. Faute: Frequent filament burnout (high failure rate)

Trigger list (engineering prevention focus)

1. Fast frequent venting of chamber, instantaneous airflow impact on thermal wire
2. Continuous deposition of process oil mist and evaporation coating material on thermal wire
3. Overpressure shock (＞0.2 MPa absolute)
4. Combustible / corrosive gas entering gauge tube (prohibited for this model)
5. Upside-down installation, condensate dripping directly onto thermal wire

Contre-mesures: Install front oil trap, slow venting, add isolation valve, installation verticale, restrict process gas

✅ Quick Self-Check Sequence (on-site recommended order)

1. Mesurer la tension d'alimentation (pin1, pin2) → rule out reverse polarity / sous-tension
2. Measure analog output (pin3, pin5), first check if it is 0~0.5V fault state
3. Cross-test with spare cable to separate gauge fault or cable / backend acquisition fault
4. Static atmosphere test, check whether reading stabilizes at atmospheric pressure
5. Isolated vacuum test to distinguish 【gauge drift】 or 【chamber leakage / pump issue】
6. Étalonnage, check mounting posture, oil baffle and sealing

⚠️ Important Disclaimer

Thermal wire contamination, oil fouling and burnout caused by dust are not covered under warranty. The manufacturer usually only supplies replacement gauge heads instead of repair.

Do not disassemble gauge head or flush internal thermal wire with solvent, permanent damage may occur immediately.

Pirani gauge is gas-dependent and not universal vacuum gauge; correction is mandatory for Ar, He, H₂.

Chengzhen (Chengdu Zhenghua ZHAC) Liste complète des modèles

Marque: Chengzhen / Chengdu Zhenghua Electronic Instrument; grouped by category; APG Pirani transmitter (your main model) au sommet

1. Pirani / Resistance Vacuum Transmitters (Integrated transmitter gauge, PLC direct acquisition, equivalent to INFICON PSG500)

APG-500C: Standard Pirani resistance transmitter, RJ45, logarithmic output 1.9~10V, KF16

APG-500CC: Version with adjustable relay threshold output

FPG550: Résistance + piezoresistive composite transmitter (large gamme, atmosphere down to rough vacuum)

ATG-530: 1Torr range precision transmitter

2. Vacuum Gauge Tubes (Separate type, requires matching indicator)

Resistance Gauge (Pirani)

ZJ-52T: Classic resistance vacuum gauge tube (glass gauge, KF, CF flange options)

Thermocouple Gauge

ZJ-51

ZJ-53B

ZJ-54D (Short-filament thermocouple, widely used in coating industry)

Piezoresistive Gauge

ZJ-1P: Piezoresistive vacuum gauge, 0.1~100kPa, suitable for near-atmosphere rough vacuum

Capacitance Diaphragm Gauge (Gas-independent, haute précision)

ZJ-1C Series (Range options: 10T, 100T, 1000T, 0~1000Pa; 4-20mA / 0-10Sortie V)

Hot Cathode Ion Gauge (B-A gauge, high vacuum)

ZJ-2

ZJ-10

ZJ-12 (B-A ultra-high vacuum gauge)

ZJ-27 (Wide-range ion gauge, mainstream for coating machines)

Cold Cathode Ion Gauge (Penning / inverted magnetron cold gauge, high vacuum, no filament)

ZJ-14 (Inverted magnetron cold gauge)

ZJ-14C (Penning cold gauge)

3. Single-type Vacuum Indicators (Panel mount for control cabinet)

ZDR Resistance (Pirani) Vacuum Meter

ZDR-I-Pro: Single-channel resistance vacuum meter

ZDR-II-Pro: Dual-channel resistance vacuum meter

ZDR-X-LED: Rack-mount multi-channel resistance vacuum mete

ZDO Thermocouple Vacuum Meter

ZDO-I / ZDO-II: Célibataire / dual channel thermocouple vacuum meter

ZDK Hot Cathode Ion Vacuum Meter

ZDK-I-LED, ZDK-X-LED: Célibataire / multi-channel ion meter, compatible with ZJ-27/ZJ-

ZDV Cold Cathode Ion Vacuum Meter

ZDV-I-LED, ZDV-IC-LED: Dedicated indicator for cold gauge

PDM Miniature Resistance Vacuum Meter (Compact, portable all-in-one)

PDM-5203: Panel miniature resistance vacuum meter (match APG, ZJ-52T)

PDM-520B: Handheld miniature vacuum meter (5Alimentation V, field portable)

4. ZDF Composite Vacuum Meter (Industry mainstream, résistance + ion / thermocouple / cold gauge combination, standard for coating machines)

ZDF-I-LED / ZDF-I-PRO: Thermocouple + ion composite

ZDF-III-LED / ZDF-III-PRO: Résistance (ZJ52T) + hot cathode ion (ZJ27), le plus courant

ZDF-IV-LED / ZDF-IV-PRO: Résistance + B-A ultra-high ion gauge (ZJ12)

ZDF-V-LED / ZDF-V-PRO: Résistance + cold cathode cold gauge (ZJ14)

ZDF-X-LED / ZDF-X-PRO: Dual resistance + single ion

ZDF-IB / ZDF-VB / ZDF-VC: Dual thermocouple, dual resistance cold gauge, dual ion and other special composite versions

5. Automatic Pressure Controller (Vacuum closed-loop pressure stabilization control)

ZDC-I: Résistance + ion composite pressure controller

ZDRC-I: Resistance pressure controller

ZDMC-I: Capacitance gauge pressure controller

ZDFC-III: Composite vacuum pressure controller

6. Accessoires assortis

ZDT-5: Electromagnetic fine-tuning vacuum valve (for pressure controller)

Ceramic sealed vacuum feedthrough electrode (vacuum electrode, vacuum feed wire)

KF/CF flange adapter, gauge cable, dedicated APG RJ45 cable

Quick Selection Reference for BOM

Rough vacuum, PLC acquisition, replace PSG500 → APG-500C / APG-500CC

Indicator display + rough vacuum → ZDR series + ZJ-52T

Standard coating machine composite vacuum (1e5~1e-5Pa) → ZDF-III-PRO + ZJ52T+ZJ27

Ultra-high vacuum → ZDF-IV + ZJ12

Filament-free, long-term high vacuum → ZDF-V + ZJ14C

Gas-independent high-accuracy absolute pressure → ZJ-1C capacitance gauge