Highly-integrated IO-Link temperature sensor reference design

March 26, 2015 // By Graham Prophet
Maxim Integrated’s IO-Link smart temperature sensor reference design lowers cost and increases uptime for industrial control and automation; the company says it is more flexible, robust, and lower cost than any discrete alternative

The MAXREFDES42# IO-Link resistance temperature detector (RTD) joins the Maxim Integrated’s portfolio of IO-Link reference designs for industrial control and automation. This design’s highly integrated analogue front end (AFE) measures temperature, while detecting overvoltage, shorts, and open circuits. This is a set of capabilities not found in competitive discrete solutions. The reference design consumes minimal power and provides better than ±0.5°K accuracy. The temperature appears immediately on an LED display for a quick and convenient snapshot of coarse temperature values. For user convenience, MAXREFDES42# fits in a standard industrial form factor. For versatility, it supports all three IO-Link speeds—no other competing device can do this. The MAXREFDES42# is available for use with a 2-wire, 3-wire, or 4-wire PT100 RTD over a wide temperature range. Applications include air, gas, and liquid temperature measurement.

The configuration software for this smart IO-Link temperature detector was developed in collaboration with IQ² Development . The MAXREFDES42# its their IO-Link device stack to communicate with any IO-Link version 1.1-compliant master. This software control lowers operating cost because it enables fast setup, diagnosis, and event monitoring from a PC and without a trip to the installation site. Maintenance can be done at the PC and not on the floor.

The design features;

Low Power: during operation over a temperature range of -40 °C to +150 °C, the system consumes less than 300 mW of power by using an industrial DC-DC step-down converter.

Highly Integrated: integrated into the front-end is the MAX31865 RTD-to-digital converter which provides flexibility, robustness, and optimal performance for an IO-Link platform.

Cost Savings: PC control with IQ² software saves configuration and maintenance cost and increases uptime.

The MAXREFDES42# design consists of an industry-standard Maxim Integrated IO-Link device transceiver (MAX14821), an efficient high-voltage step-down converter (MAX15062B), a Renesas ultra-low-power 16-bit microcontroller (RL78) with IQ 2 Development’s IO-Link device stack, and a highly integrated RTD-to-digital converter (MAX31865).

The MAXREFDES42# reference design is available for $99.