DS1920 | GUILCOR SENSORS

DS1920
Temperature sensors

Pt10 temperature sensors provide accurate and reliable temperature measurement for industrial applications requiring low nominal resistance.

Maximum precision
+/- 0,50°K

Minimum temperature
-55°C

Maximum temperature
+100°C

Minimum dimensions
17,35 x 5,9

Response time
Medium

Self-heating
Low

Price
High

Drift
Low

What is a DS1920 sensor ?

The DS1920 is a digital temperature sensor encapsulated in a stainless steel iButton housing.

It integrates the same chip as the DS18S20, but protected by a waterproof and extremely robust metal casing.

Each iButton contains:

a 9-bit digital thermal sensor,
a unique 64-bit identification,
and a standard 1-Wire interface.

Its mechanical design makes it a preferred choice for:

cold chain management,
transport traceability,
or challenging industrial environments.

Operating principle

The DS1920 operates exactly like the DS18S20, with a 9-bit internal conversion and transmission via the 1-Wire bus:

T(°c) : Raw Value / 16

The metal housing acts as a heat sink and ensures excellent inertia and measurement stability.

Technical specifications

Parameter	Typical Value
Measurement range	−55 °C → +100 °C (case)
Typical precision	±0,5 K (−10 → +85 °C)
Resolution	9 bits (0,5 °C)
Conversion time	750 ms
Interface	1-Wire Digital
Alimentation	3.0–5.5 V (or parasitic)
Unique identifier	64 bits
Case	iButton (sealed stainless steel)
Annual drift	Low (±0.2 K/year)

Wiring configuration

Type	Description	Precision
1-Wire	Signal DATA + mass via metal connector	✅ Standard
Parasite	Power supply via DATA + metal mass	💡 Mobile applications
Multi-drop	Network of several iButtons in parallel	🏗️ Thermal tracking chains

The DS1920 connects using an iButton connector or a standard 1-Wire reader, often mounted on a magnetic support or contact plate.

Self-heating

Very low (< 0.3 °C), the metal casing acts as a natural heat sink.

Application areas

🧊 Cold chain monitoring (food, pharma)

🚛 Temperature tracking during transport

🏭 Robust industrial environments or subjected to shocks

🔋 Identification + measurement systems (iButton loggers)

🧠 Embedded projects requiring traceability and mechanical resistance

Should I choose a DS1920 sensor ?

Strengths points

🧱 Ultra-robust design
→ Sealed stainless steel iButton case, shock-resistant, moisture-resistant, and thermal variation-resistant. Ideal for industrial environments, logistics chains, and mobile applications.
🎯 Reliability and traceability
→ Each sensor has a unique 64-bit identifier, allowing for precise tracking of each measurement point — perfect for temperature traceability in transport or maintenance.
💧 Excellent thermal inertia
→ The metal casing ensures a stable and filtered measurement, minimally sensitive to instantaneous fluctuations or electrical noise.

Weaknesses points

📉 Limited to 9 bits resolution
→ Each step equals 0.5 °C sufficient for monitoring, but not for laboratory measurements.
💰 Higher cost than a standard DS18B20
→ The mechanical design (iButton casing, specific connectors) results in a higher price.
🔌 Proprietary connectivity
→ Requires an iButton support or dedicated 1-Wire reader, limiting plug-and-play compatibility with standard cards.

Useful information

Here is some useful information regarding the DS1920 sensors.

Resolution and precision

The DS1920 uses the same chip as the DS18S20, with a fixed resolution of 9 bits (0.5 °C per step).

Its metal casing acts as a heat sink, ensuring very stable measurements and minimal drift over time.

Resolution	No measurement (°C)	Conversion time	Accuracy (−10 → +85 °C)	Extended accuracy (−55 → +100 °C)
9 bits	0,5 °C	750 ms	±0,5 K	±1,0 K

🔹 Remarks:

Factory calibrated accuracy.
Low annual drift (±0.2 K/year).
The iButton case ensures stable and filtered measurement.

Application example – Reading a DS1920

The measured temperature is encoded on 9 signed bits and transmitted via the 1-Wire bus.

The conversion equation remains simple:

T(°C) = Raw Value / 16

🔹 Example 1 – Positive Reading

The sensor returns:

LSB = 0x50
MSB = 0x00
Raw value 0x0050 = 80₁₀ T = 80 / 2 = 40,0 °C
✅ Result: measured temperature = 40.0 °C

🔹 Example 2 – Negative reading

The sensor returns:

LSB = 0x90
MSB = 0xFF

0xFF90 = -112₁₀ T = -112 / 2 = -56,0 °C

✅ Result: measured temperature = −56.0 °C

🔹 Practical notes

Reading via “Read Scratchpad” command (0xBE).
The internal memory contains: temperature, alarm thresholds, CRC.
No configuration required: the resolution is fixed at 9 bits.

Integration diagram in an electronic system

The DS1920 is used via an iButton reader (or "F5 MicroCan Socket") connected to the 1-Wire bus.

The metal body serves as ground (GND) and the central contact corresponds to the DATA line.

🔹 Typical components

Component	Function
DS1920 iButton	Encapsulated steel temperature sensor
Support iButton (F5)	Interface DATA + GND
Resistance 4.7 kΩ	Data bus draw
Microcontroller (Arduino, ESP32, STM32)	1-Wire Bus Master
Power Supply 3.3 V / 5 V	Source for the bus

🔹 Functional diagram (ASCII)

+3.3V / +5V │ [4.7kΩ] │ DATA ────────┼───────────────┐ │ │ Support iButton µC (1-Wire input) │ [DS1920] (metal case) │ GND

🔹 Operating Principle

1️⃣ The microcontroller initializes the bus and detects the presence of the iButton.

2️⃣ The central contact sends the data; the housing ensures the ground return.

3️⃣ A "Convert T" command (0x44) initiates the measurement.

4️⃣ After 750 ms, the temperature is read via "Read Scratchpad" (0xBE).

Multi-point advantage – Robustness and identification

Each DS1920 has a unique 64-bit identifier engraved at the factory.

This allows multiple sensors to be combined on the same bus while ensuring perfect traceability.

Function	Description
Unique 64-bit ID (0x10)	Permanent individual identification
Waterproof metal casing	Resistant to shocks, vibrations, and humidity
Simple chaining	Several iButtons connected on the same bus
Quick maintenance	Replaceable sensor without reconfiguration