Solution · Cleanroom Monitoring
Cleanroom Differential Pressure Monitoring
Measure, display and alarm on the pressure difference between controlled rooms and adjacent areas, then send the values to your building management, PLC or remote monitoring system with POLWAX differential pressure transmitters.
The Challenge
Keeping air moving in the right direction
Cleanrooms and controlled areas rely on a defined pressure relationship with the rooms around them, so that air flows from cleaner areas towards less clean ones. Door openings, filter loading and changes in the ventilation system can all disturb that balance.
The pressure differences involved are small, so they need instruments that resolve low ranges, show the value at the room and warn staff when the relationship is lost.
- Continuous indication of room-to-room pressure difference
- Local alarm when the pressure relationship is not maintained
- Values available to BMS, PLC or remote monitoring for records
- Related room conditions such as temperature and humidity
The POLWAX Solution
Measure, indicate, alarm and integrate
POLWAX DPT series transmitters measure the pressure difference between two points through 3/16" tubing, show it in Pa or mmWC and pass it on in the form your system needs.
-
Measure
Low, bi-directional differential pressure ranges starting from 0–10 mm WC on the DPT20 and DPT30.
-
Indicate
Local reading at the room, in Pa or mmWC, configured with the front keys or, on the DPT50 WM, via USB.
-
Alarm
Inbuilt buzzer on DPT20 and DPT30 alarm versions, and a relay option on the DPT30 for external signalling.
-
Integrate
4–20 mA, 0–10 V and RS485 Modbus RTU options to connect to BMS, PLC or the CloudWAY IoT gateway.
How It Works
From the room to your monitoring system
-
Pressure taps
Tubing connects the cleanroom and the reference area to the transmitter's push-on 3/16" ports.
-
Transmitter
A DPT series transmitter measures the difference and shows it locally in Pa or mmWC.
-
Local alarm
Alarm versions sound a buzzer; the DPT30 relay option can switch an external signal.
-
Signal output
4–20 mA, 0–10 V or RS485 Modbus RTU, depending on the model and order code.
-
Monitoring
Values go to your BMS, PLC or SCADA, or through a CloudWAY gateway over WiFi, Ethernet or GSM.
Add a ClimaTRANS RHT100 in the same room to send temperature and humidity over the same RS485 Modbus RTU network.
Recommended Products
POLWAX instruments for cleanroom pressure monitoring
Specifications are taken from the POLWAX product pages and may change. Please check the current datasheet or ask our team before ordering.
-
Differential pressureDPT20 Differential Pressure Transmitter
Panel-mount transmitter with an inbuilt buzzer or 4–20 mA output, for room and filter pressure monitoring.
- Ranges
- 0–10 to 0–250 mm WC, bi-directional
- Accuracy
- ±0.5 % FS (ranges ≥ 0–25 mm WC); ±1.0 % FS (≤ 0–10 mm WC)
- Output
- Inbuilt buzzer / 4–20 mA; 0–10 V optional
- Supply
- 12–24 VDC · panel mounting
-
Differential pressureDPT30 Differential Pressure Transmitter
Extends the DPT20 platform with wider ranges and more output options, including RS485 Modbus RTU and relay.
- Ranges
- 0–10 to 0–700 mm WC, bi-directional
- Accuracy
- ±0.5 % FS (ranges ≥ 0–25 mm WC); ±1.0 % FS (≤ 0–10 mm WC)
- Outputs
- Alarm (buzzer), 0–10 V, 4–20 mA, relay, RS485 Modbus RTU (order options)
- Units
- Pa & mmWC · response time 500 ms
-
Differential pressureDPT50 WM / DPT100 WM / DPH100 WM
High-precision transmitters configured via USB; the DPH100 WM also measures temperature and humidity.
- Accuracy
- 0.25 % / 0.5 % of FS
- Outputs
- 4–20 mA (std.), 0–10 V (optional), RS485 Modbus RTU
- Config
- USB interface · selectable pressure units
- DPH100 WM
- T: -30 to 80 °C · RH: 0–100 %
-
Temperature & humidityClimaTRANS RHT100
Industrial temperature and humidity transmitter with TFT display for the same controlled rooms.
- Accuracy
- ±0.3 °C (0–60 °C) · ±1.8 % RH at 23 °C (0–90 % RH)
- Output
- RS485 Modbus RTU
- Display
- TFT · wall or duct mount
- Protection
- IP65
-
ConnectivityCloudWAY IoT Gateway GT400 / GT800
Connects 4–20 mA and Modbus RS485 transmitters to remote monitoring.
- Channels
- 4 (GT400) / 8 (GT800)
- Inputs
- 4–20 mA / Modbus RS485
- Network
- WiFi / Ethernet / GSM
- Protocols
- MQTT, Modbus, HTTP
-
Not sure which model?Get a recommendation
Tell us the number of rooms, the pressure range you expect, whether you need a local alarm and how the values should reach your system. Our team will suggest suitable models and options.
Contact our team
Key Benefits
Why use POLWAX for cleanroom pressure
-
Bi-directional ranges
All DPT20 and DPT30 ranges are bi-directional, so a reversal of the pressure relationship is still measured.
-
Alarm at the room
Buzzer versions alert staff on site, without depending on a remote system.
-
Flexible integration
Analogue, relay and RS485 Modbus RTU options to suit BMS, PLC and SCADA systems.
-
Calibration certificate supplied
The DPT20, DPT30, DPT50 WM and RHT100 are each supplied with a calibration certificate and manual.
-
Complete room picture
Combine pressure with temperature and humidity using the RHT100 or the DPH100 WM.
-
Remote monitoring option
The CloudWAY gateway sends transmitter values over WiFi, Ethernet or GSM.
Industries & Use Cases
Where differential pressure monitoring is used
-
Pharmaceutical & biotech cleanrooms
Room-to-room pressure, airlocks and controlled production areas.
-
Laboratories & research facilities
Controlled lab rooms that depend on a defined pressure relationship.
-
HVAC & air handling
Filter loading, fan and airflow monitoring that keep cleanroom supply air stable.
-
Building automation
Pressure values fed into BMS for smart ventilation control and records.
Product suitability depends on the model, configuration and the requirements of your facility, including any regulatory or validation requirements. Please contact our team to confirm the right instrument for your application.
Technical Resources
Datasheets and documentation
Datasheets and manuals for these products are available on request.
FAQ
Frequently asked questions
Which model gives a local alarm at the room?
The DPT20 is available with an inbuilt buzzer, and the DPT30 offers an alarm with inbuilt buzzer plus a relay output option. The output type is selected by order code.
Can the pressure readings go to our BMS or PLC?
Yes. The DPT30 offers 4–20 mA, 0–10 V and RS485 Modbus RTU options; the DPT50 WM series provides 4–20 mA as standard, 0–10 V as an option and RS485 Modbus RTU; the DPT20 offers 4–20 mA with 0–10 V optional.
What does bi-directional mean for cleanroom monitoring?
All DPT20 and DPT30 ranges are bi-directional, so the transmitter measures the pressure difference in both directions. If the intended relationship between two rooms reverses, the reading still shows it.
In which units are readings shown?
The DPT20 and DPT30 measure in Pa and mmWC. The DPT50 WM series has selectable pressure units, configured via its USB interface.
How accurate are the lowest ranges?
For the DPT20 and DPT30, accuracy is ±1.0 % of full scale for ranges up to 0–10 mm WC and ±0.5 % of full scale for ranges from 0–25 mm WC. The DPT50 WM series is specified at 0.25 % / 0.5 % of full scale.
Is a calibration certificate included?
The scope of supply listed for the DPT20, DPT30, DPT50 WM series and ClimaTRANS RHT100 includes a calibration certificate and a manual.
Can we monitor several rooms remotely?
The CloudWAY IoT gateway accepts 4 (GT400) or 8 (GT800) channels of 4–20 mA or Modbus RS485 instruments and communicates over WiFi, Ethernet or GSM using MQTT, Modbus or HTTP.
Plan your cleanroom pressure monitoring
Share your room layout, expected pressure range and integration needs, and our team will recommend suitable POLWAX instruments.