Wi-Fi RTD Temperature Sensor

A Wi-Fi RTD temperature sensor is a transmitter that reads a platinum resistance probe — a PT100 or PT1000 — and sends the temperature over an ordinary Wi-Fi network to a server or cloud platform. The probe provides the accuracy and range of an industrial instrument, and Wi-Fi removes both the signal cable and the gateway. It is also called a Wi-Fi PT100 temperature sensor, a wireless PT100 transmitter or a Wi-Fi temperature data logger with a probe.

An RTD, or resistance temperature detector, is a sensor whose electrical resistance rises with temperature in a precisely known way. Industrial RTDs use platinum. A PT100 has a resistance of 100 Ω at 0 °C and a PT1000 has 1,000 Ω at 0 °C; both follow the IEC 60751 standard curve. The transmitter measures the resistance and converts it to a temperature.

If PT100 probes are already installed, keep them and use the MacSync W RTD X2. For new installations the PT1000 on the X5 is usually the easier choice, because the wire between probe and transmitter matters ten times less: 1 Ω of lead resistance reads as about 2.6 °C on a two-wire PT100 but only about 0.26 °C on a PT1000. Both types follow IEC 60751 and are made in the same tolerance classes.

The transmitter is accurate to ±0.2 °C typical, with 0.1 °C resolution, ±0.05 °C repeatability and less than 0.05 °C of drift a year. The probe adds its own tolerance, as with every RTD transmitter. Under IEC 60751 a Class A probe is within ±(0.15 + 0.002 × t) °C and a Class B probe within ±(0.30 + 0.005 × t) °C, where t is the temperature in °C without its sign — so at 100 °C that is ±0.35 °C for Class A and ±0.8 °C for Class B.

The RTD input measures from −200 °C to +850 °C. In practice the probe and its cable set the limit, so they must be rated for the temperature they sit in. The electronics are rated from −40 °C to +80 °C, which is why the transmitter is mounted outside the hot or cold zone and only the probe goes in.

Yes. Both are inside the −200 °C lower limit of the RTD input; liquid nitrogen boils at about −196 °C. Use a probe and cable rated for that temperature, feed the probe through the freezer's port, and mount the transmitter outside where the Wi-Fi reaches and the temperature is above −40 °C.

No. The MacSync W RTD joins your existing 2.4 or 5 GHz Wi-Fi network directly and publishes to your MQTT broker or HTTPS endpoint. There is no gateway, hub or proprietary receiver to buy or maintain.

Usually not, because insulated metal walls block the signal. That is why the transmitter is mounted outside and only the probe goes inside. In a walk-in cold room that has an access point inside it, the transmitter can be mounted inside as long as the room stays above −40 °C.

The battery variant runs on a 19 Ah cell. Using our Wi-Fi battery calculator with the datasheet's sleep current, a DHCP connection and TLS, the estimate is about 1 year at 5-minute uploads, about 2.6 years at 15 minutes and about 6.8 years at hourly uploads. A static IP address shortens each connection and extends those figures. For readings every minute or two, choose the 9–36 V DC variant.

Nothing is lost. The sensor keeps measuring and stores up to 30,000 records on the device, then uploads them when the Wi-Fi or the server comes back. At one reading every 15 minutes that is about 10 months of history.

It publishes over MQTT, HTTP and HTTPS, so it works with any MQTT broker or REST endpoint: AWS IoT Core, Microsoft Azure IoT Hub, Google Cloud, a private cloud or an on-premise server, and from there SCADA, BMS or analytics systems. There is no mandatory vendor cloud.

Yes. The Wi-Fi link uses WPA2-PSK or WPA3, and data is carried with TLS/SSL encryption to the server. The firmware is protected by secure boot and signed over-the-air updates.

With the Macnman Maya Android app over Bluetooth, standing next to the device: you enter the Wi-Fi network, the server details, the upload interval and the alarm limits. Settings can also be changed later from the server.

The X2 model reads PT100 probes that follow the IEC 60751 curve, which covers standard industrial PT100s. Tell us how your probe is wired — two, three or four wires — and what connector or cable end it has before ordering, so we can confirm the fit.

The extra wires exist to cancel the resistance of the cable. A two-wire probe includes the cable resistance in the reading, which is acceptable for short leads or a PT1000. A three-wire probe lets the transmitter subtract the cable resistance and is the industrial norm for PT100. A four-wire probe removes it completely and is used in laboratories. Confirm the wiring of your probe with us when ordering.

Choose an RTD when accuracy and long-term stability matter and the temperature is between −200 and +850 °C: freezers, cold rooms, ovens, process lines and anything that is audited. Choose a thermocouple for temperatures above that, such as kilns and flames, where its lower accuracy is acceptable. The MacSync W RTD accepts RTD probes only.

It provides what a monitoring record is built from: continuous readings, threshold alerts and on-board storage that survives a network outage. Whether a complete system meets a particular regulation also depends on calibration, the software that stores the data and your own procedures, so treat the sensor as one part of a validated system.

The transmitter converts resistance to temperature using the IEC 60751 curve and drifts by less than 0.05 °C a year. Probes are made to a tolerance class rather than individually adjusted. For audited applications, verify the complete loop — probe and transmitter together — against a reference thermometer when it is installed and at the interval your quality system sets.

Typically up to 100 m indoors from the access point, depending on walls, racking and machinery. If the measuring point is in a dead spot, mount the transmitter where the signal is good and use a longer probe cable.

Yes. Where there is no Wi-Fi coverage, the MacSync LoRaWAN RTD sensor reads the same kind of probe and reports through a LoRaWAN gateway that can be kilometres away.

Yes. The MacSync W RTD is designed and manufactured by Macnman Technologies in Pune, Maharashtra. It is WPC compliant and conforms to RoHS.