Calorimetric flow meter VA 520

volumemassfor air

Product name
Thermal mass flow meter VA 520 (inline)

Brand
CS-Instruments

Product information
The VA 520 is a thermal mass (calorimetric) flow meter for inline measurement of compressed air and technical gases. It provides mass flow and standardized volume flow outputs, with very low pressure loss and no moving parts. Available in flange or threaded versions and multiple measuring section sizes suitable for monitoring consumption, leak detection and energy optimisation.

Available items (measuring sections / order numbers)
Product | Order No.
VA 520 flow meter with integrated DN 25 measuring section with flange | 0695 2523
VA 520 flow meter with integrated DN 50 measuring section with flange | 0695 2525
VA 520 flow meter with integrated DN 65 measuring section with flange | 0695 2527
VA 520 flow meter with integrated DN 80 measuring section with flange | 0695 2528

Application - technological features

• Digital interfaces: Modbus-RTU (RS485) standard; optional Ethernet (PoE) and M-Bus for integration with BMS, PLC or energy management systems.
• Simple, cost-effective inline installation; multiple measuring section sizes (DN 25–DN 80) and threaded variants.
• Units selectable via display keys: m3/h, m3/min, l/min, l/s, kg/h, kg/min, kg/s, cfm, ft/min, m/s, etc.
• Compressed air totaliser up to 1,999,999,999 m3 with reset via keypad.
• Analogue output 4…20 mA and electrically isolated pulse output (configurable pulse weight, can be used as alarm).
• High accuracy even at low flows, suitable for leakage measurement.
• Negligible pressure loss due to inline measuring section design.
• Calorimetric measuring principle: no separate pressure/temperature sensors required; no mechanical moving parts.
• Comprehensive diagnostics available on display or via Modbus (max/min exceedance, calibration cycle, error codes, serial number). All parameters readable and configurable via Modbus.

Flow measuring ranges (summary)
Flow measuring ranges VA 520 (Max version 185 m/s) for compressed air (ISO 1217: 1000 mbar, 20°C) — Flange DIN EN 1092-1
Measuring section | Outer pipe mm | Inner pipe mm | Measuring range full scales (m3/h) / (cfm)
DN 25 | 33.7 | 27.3 | 290 / 170
DN 50 | 60.3 | 53.1 | 1195 / 700
DN 65 | 76.1 | 68.9 | 2050 / 1205
DN 80 | 88.9 | 80.9 | 2840 / 1670

Monitoring of compressed air
The VA 520 is designed for compressed air and gas monitoring: it measures instantaneous flow and cumulative consumption, helps detect leaks and abnormal flow patterns, and supports system optimisation and energy savings through integration with monitoring or management systems.

Technical specifications

• Sensor type: Thermal mass flow sensor (calorimetric).
• Measured media: Air and gases (gas type selectable via CS service software or data logger: air, nitrogen, argon, CO2, oxygen, etc.).
• Units: m3/h, m3/min, l/min, l/s, ft/min, cfm, m/s, kg/h, kg/min, g/s, lb/min, lb/h (selectable).
• Accuracy: ±1.5% of measured value ±0.3% of full scale; on request ±1% of measured value ±0.3% of full scale.
• Operating temperature: -30 … 80 °C.
• Operating pressure: -1 … 16 bar (option up to PN 40).
• Digital output: RS485 (Modbus-RTU). Optional Ethernet (PoE), M-Bus.
• Analogue output: 4…20 mA for m3/h or l/min (galvanically isolated).
• Pulse output: 1 pulse per m3 or per litre, electrically isolated; pulse weight configurable; can be used as alarm relay.
• Supply: 18…36 VDC, approx. 5 W. Load < 500 Ω.
• Housing: Polycarbonate, IP65.
• Measuring section material: Stainless steel (1.4404 or 1.4571).
• Process connection: Flange (DIN EN 1092-1) or ANSI (150/300 lbs) available; threaded variants available.
• Mounting position: Any.
• Weight: approx. 3.5 kg.
• Example product number / SKU: 0695 2523 (DN 25 flange version).