S305 Dew Point Monitor for Desiccant and Fridge Dryers (-50… +20 °C Td / -20 … +50 °C Td)

Simple and cost-efficient dew point monitoring, by serving as a measuring and display device.

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Plug & Play solution for easy installation and usage

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Precise measurement with ± 2 °C Td accuracy

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Fast response time for time-efficient measurements

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Alarm indication with internal relays or alarm units

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-50 ... +50 °C Td depending on the model

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Easy process connection via 6 mm quick connect

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4 … 20 mA signal output to PLC or SCADA system

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Operating pressure of 0.3 ... 1.5 MPa

The SUTO S305 Dew Point Monitor offers a simple and inexpensive dew point monitoring solution, with alarm options. The all-in-one solution serves as a dew point measuring and display device for desiccant and fridge dryers.

Alarm Indications Before It Is Too Late

Refrigeration dryers are among the dryers in compressed air treatment most commonly used. If the required drying is not achieved, the impact of wet air can be serious: Rust in the pipes, failures of machines, and a negative impact on product quality.

The S305 Dew Point Monitor has an optical red backlight which blinks when an alarm is triggered as well as 2 alarm relays which can be used to connect to alarm lights and sirens to warn when dew points are not within the pre-defined ranges. Two alarm levels can be programmed (pre and main alarm).

Two Measurement Range Models

The S305 can be ordered in two ranges, to perfectly fit your needs:

  • Option 1: -50… +20 °C Td
  • Option 2: -20 … +50 °C Td
Various Connection Options

The connection to the compressed air network is via a 6 mm quick-connector and corresponding connecting hose. The 4 … 20 mA output can be used to connect the dew point monitor to a PLC or a SCADA system.

Easy Installation and Robust Design

The entire measuring unit is integrated with the display in a rugged housing. The IP65 casing provides robust protection in harsh industrial environments. The dew point monitor is available both as a panel variant or as a wall-mounted housing.

SUTO Exchange Service

The exchange calibration service eliminates downtime and enables users to have a seamless record of their dew point measurements. Learn more about our exchange calibration service here.

For further requests and consultation please contact us here.

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  • Monitor fridge and desiccant driers
  • Simple after-market installation
  • Monitoring of process humidity and notification in case of alarms
  • Control dew point temperature at a single glance


Dew Point
Accuracy±2 °C Td
Selectable units°C, °F
Measuring range (model depending)-50 ... +20 °C Td
-20 ... +50 °C Td
Response time t90 (@ 4l/min)-50 °C Td -> -20 °C Td = 20 sec
0 °C Td -> -40 °C Td = 120 sec
Accuracy0.3 °C
Measuring range-30 ... +70 °C
Reference conditions
Selectable conditionsPressure Dew Point


Analog output
Signal4 ... 20 mA 3-Wire
Scaling-50 ... +20 °C Td or -20 ... +50 °C Td
Update rate3 / sec
Voltage supply (model depending)100 ... 240 VAC ; 50/60 Hz
24 VDC
Current consumption (model depending)40 mA @ 220 VAC
120 mA @ 24 VDC


PC SoftwareS4C-Display Software
OthersInstrument comes pre-configured Plug & Play
IntegratedLCD Display, indicates values and alarms
Process connectionStainless steel 1.4301 (SUS 304)
HousingABS, Aluminium alloy
Metal partsSinter Filter (stainless steel)
Electrical connectionScrew terminals
Protection classIP65
Process connection6 mm quick connector
Weight520 g
Operating conditions
MediumNon-corrosive gases
Medium qualityISO 8573-1: 4.6.3 or better
Medium temperature-30 ... +70 °C
Medium humidity≤ 20 °C Td or ≤ 50 °C Td (model depending)
Operating pressure0.3 ... 1.5 MPa
Ambient temperature-10 ... +40 °C
Ambient humidity0 ... 100 % rH
Storage temperature0 ... +40 °C
Transport temperature-30 ... +70 °C
Stated accuracy under following conditions:
Ambient temperature 23 °C ±3 °C
Process temperature 23 °C ±3 °C
Ambient humidity < 95 %, no condensation
Airflow > 2 l/min at sensor tip


Info sheets
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Successfully Copied

S305 / S320 Firmware: V 2.23

Firmware This version is only for use with GD board 0460 0604, and 0460 0533 will keep to
use V2.04
S305 / S320 Firmware: V 2.23

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