APG‑500C Precision Resistance (Pirani) Vacuum Transmitter

Numele complet: APG-500C Precision Resistance (Pirani) Vacuum Transmitter (Pirani Gauge)

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

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

✅ Key Specifications

Principiul de măsurare: Pirani (thermal conduction resistance vacuum gauge)

Domeniul de măsurare: 5×10⁻² Pa ～ 1×10⁵ Pa (Aer / N₂)

Alimentare electrică: 13.5～30 VDC, Power consumption ≤2W, Max inrush current ＜300mA

Ieșire analogică: Logarithmic voltage 1.9～10.0 VDC (0~0.5V indicates filament failure)

Interfață electrică: RJ45 (8-core FCC68)

Vacuum Flange: Standard KF16 (mainstream version)

Max Pressure Withstand: ≤0.2 MPa (presiune absolută)

Timp de răspuns: 100 Domnișoară

Mounting Requirement: Instalare verticală, keep away from heat sources and vibration sources

Media aplicabile: Aer, 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 VDC
3. HV zero calibration: Pump down to ≤1×10⁻² Pa, set to 1×10⁻² Pa → 1.5 VDC

📌 Matching Products & Alternative

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

Coating machines, vacuum furnaces, leak detection systems, vacuum packaging, negative pressure processes, coarse & medium vacuum monitoring for semiconductor

APG-500C (Chengzhen/Zhenghua) Lista de verificare pentru depanare

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

Instrumente necesare: Multimeter for RJ45 pin voltage measurement, megahmmetru, standard vacuum source, leak detector

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

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

Cauze fundamentale:

1. Burned platinum thermal wire (most frequent; 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

Pași de depanare:

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

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

2. Vina: Nicio ieșire, no signal on meter, floating reading on PLC

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

Cauze fundamentale:

1. Lipsește sursa de alimentare, reverse polarity, siguranța arsă
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)

Pași de depanare:

① Measure voltage pin1-pin2, verify polarity (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

Remediu: Replace cable, correct power polarity, use compatible acquisition channel

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

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

Cauze fundamentale:

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

Pași de depanare:

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: Instalare verticală, flange downward or lateral; avoid upside-down installation which causes liquid accumulation

⑤ Isolate gauge and perform leak test for chamber leak rate

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

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

Simptom: Vacuum is stable but reading jumps back and forth

Cauze fundamentale:

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

Pași de depanare:

① Use isolated DC power supply for independent gauge power supply

② Single-end grounding for cable shield, țineți departe de cablurile de alimentare

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

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

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

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

Cauze fundamentale:

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. Defecțiunea circuitului intern, output locked at full scale

Pași de depanare:

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

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

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

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

Cauze fundamentale:

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

Pași de depanare:

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

Remediu: Recalibrați; replace whole transmitter if contacts damaged

7. Vina: 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

Countermeasures: Install front oil trap, slow venting, add isolation valve, instalare verticală, restrict process gas

✅ Secvență rapidă de autoverificare (on-site recommended order)

1. Measure supply voltage (pin1, pin2) → rule out reverse polarity / subtensiune
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. Calibrare, 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) Lista completă a modelelor

Marca: Chengzhen / Chengdu Zhenghua Electronic Instrument; grouped by category; APG Pirani transmitter (your main model) at the top

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: Rezistenţă + piezoresistive composite transmitter (gamă largă, 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, precizie ridicată)

ZJ-1C Series (Range options: 10T, 100T, 1000T, 0~1000Pa; 4-20mA / 0-10Ieșire 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: Singur / dual channel thermocouple vacuum meter

ZDK Hot Cathode Ion Vacuum Meter

ZDK-I-LED, ZDK-X-LED: Singur / 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 (5sursa de alimentare V, field portable)

4. ZDF Composite Vacuum Meter (curentul general al industriei, rezistenţă + ion / thermocouple / cold gauge combination, standard for coating machines)

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

ZDF-III-LED / ZDF-III-PRO: Rezistenţă (ZJ52T) + hot cathode ion (ZJ27), cele mai frecvente

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

ZDF-V-LED / ZDF-V-PRO: Rezistenţă + 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: Rezistenţă + ion composite pressure controller

ZDRC-I: Resistance pressure controller

ZDMC-I: Capacitance gauge pressure controller

ZDFC-III: Composite vacuum pressure controller

6. Accesorii potrivite

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