VA 500

CS Instruments – VA 500

Highly accurate thermal measuring probe for reliable flow and consumption measurement, with assembly and disassembly under pressure.

Measuring principle Thermal mass flow

Medium Compressed air and technical gases

Measuring range 1/2" to DN 300+

Accuracy ±1.5% of measured value (optional ±1%)

Operating pressure -1 to 50 bar

Outputs / communication RS 485 (Modbus RTU), 4–20 mA, pulse output

Special feature Assembly and disassembly under pressure

Standard measuring range version (92.7 m/s)Base version for most compressed air and gas flow measurement applications.
Threaded connection G 1/2" (male thread)Standard connection for probe installation via a 1/2" measuring point (e.g. ball valve).
Integrated displayBuilt-in indication of flow and totalizer (e.g. m³/h and m³) for quick local readout.
RS 485 (Modbus RTU)Industrial digital interface for connection to a control system or data logger.
Standard accuracyMeasurement accuracy ±1.5% of reading and ±0.3% of full scale.

Parameter	120 mm	160 mm	220 mm	300 mm	400 mm	500 mm	600 mm	700 mm
Parameters (basic)	m³/h, l/min (1000 mbar, 20 °C) for compressed air; Nm³/h, Nl/min (1013 mbar, 0 °C) for gases
Display units (configurable)	m³/h, m³/min, l/min, l/s, ft/min, cfm, m/s, kg/h, kg/min, g/s, lb/min, lb/h
Settings via keypad	Pipe diameter for flow calculation, totalizer reset, reference conditions (°C/mbar), 4–20 mA scale, pulse value
Sensor	Thermal mass flow sensor
Measured medium	Air, gases
Gas types (configurable)	Air, nitrogen, argon, helium, CO₂, oxygen, vacuum
Measuring range	Depending on pipe diameter (manufacturer table)
Accuracy (standard)	± 1.5% of reading + ± 0.3% of full scale
Accuracy (optional)	± 1% of reading + ± 0.3% of full scale
Operating temperature (probe) [°C]	-30 … +110
Operating temperature (with pressure measurement) [°C]	-20 … +85
Operating temperature (housing) [°C]	-20 … +70
Operating pressure [bar]	-1 … 50 (for pressure > 10 bar, additional high-pressure protection is recommended)
Digital interfaces	RS-485 (Modbus RTU) standard; optional Ethernet (PoE), M-Bus, IO-Link
Analog output	4–20 mA for m³/h or l/min
Pulse output	1 pulse per m³ or liter (galvanically isolated); adjustable pulse value; can also be used as alarm
Power supply	18 … 36 VDC, 5 W
Load	< 500 Ω
Housing	Polycarbonate (IP 65)
Probe material	Stainless steel 1.4301
Standard insertion length [mm]	220
Probe diameter [mm]	Ø 10
Mounting thread	G 1/2" (male thread)
Housing diameter [mm]	Ø 65
Mounting position	Any