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MAXREFDES1154: Configurable 4-Channel RTD/TC Measurement System Using the MAX11410

MAXREFDES1154

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Description

The MAXREFDES1154 is a configurable 4-channel RTD/ TC measurement system. Each channel can be configured as either RTD input or TC input using RTD for cold junction compensation. The RTD can either be PT100 or PT1000 connected in 2-wire or 3-wire configuration. The same configuration can also be used to measure resistance. MAXREFDES1154 also supports all types of thermocouples, using RTD for cold junction compensation, which can be PT100 or PT1000, but it needs to be configured as a 2-wire connection.

The MAXREFDES1154 provides a complete system solution for highly accurate temperature measurement in industrial applications. Analog front end includes two 8:1 multiplexer MAX4617 and one 4:1 multiplexer MAX4704 for RTD/TC input selection, and one 24-bit, 10-channel ADC MAX11410.

The microcontroller on board is used to communicate with the MAX11410 ADC, control the multiplexers, and process the ADC conversion results. The 24V field input power supply is isolated from both the analog front end and the microcontroller, which is powered using a USB. Isolation enhances system robustness, an important consideration in harsh industrial applications.

The MAXREFDES1154 design integrates two 8:1 multiplexer (MAX4617) and one 4:1 multiplexer (MAX4704), a 24-bit 10-channel ADC with internal PGA buffers (MAX11410), a high-precision 1.250V voltage reference (MAX6071), 2.75kVRMS digital isolator (MAX14930 and MAX14931), a STM32F1 microcontroller, a μP supervisor (MAX6730), a FTDI USB-UART bridge, a high-efficiency Iso-Buck DC-DC converter (MAX17681), and an isolated/regulated +3.3V power rail (MAX16910). The entire system typically consumes less than 300mW and fits onto a 5cm x 9cm board. It is targeted for industrial PLC applications.

Features

  • Highly accurate measurement
  • Four channels
  • Each channel can be configured as either RTD or TC input
  • Supports 2-wire and 3-wire RTD
  • Supports all types of thermocouple
  • Thermocouple with RTD for cold junction compensation
  • Sensor open detection
  • 24V input protection
  • Isolated power and data
  • Board-level calibration

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Designed, Built, Tested

Board pictured here has been fully assembled and tested. Not available for sale.

 

Maxim Devices (8)

Part Number Name Product Family Order Design kits and evaluation modules
MAX11410 24-Bit Multi-Channel Low-Power 1.9ksps Delta-Sigma ADC with PGA Analog-to-Digital Converters Buy Now Design Kits
MAX4617 High-Speed, Low-Voltage, CMOS Analog Multiplexers/Switches Switches and Multiplexers Buy Now Not Available
MAX4704 Low-Voltage, 60Ω, 4:1 Analog Multiplexer in QFN Switches and Multiplexers Buy Now Not Available
MAX14930 4-Channel, 1kVRMS, and 2.75kVRMS, Digital Isolators Isolation Buy Now Design Kits
MAX14931 4-Channel, 1kVRMS, and 2.75kVRMS, Digital Isolators Isolation Buy Now Design Kits
MAX6730 Single-/Dual-/Triple-Voltage µP Supervisory Circuits with Independent Watchdog Output Voltage Supervisors Buy Now Not Available
MAX17681 4.5V to 42V Input, High-Efficiency, Iso-Buck DC-DC Converter Isolated Power Buy Now Design Kits
MAX16910 200mA, Automotive, Ultra-Low Quiescent Current, Linear Regulator Linear Regulators (LDOs) Buy Now Design Kits

Maxim Devices (8)

Part Number Product Family
Analog-to-Digital Converters
24-Bit Multi-Channel Low-Power 1.9ksps Delta-Sigma ADC with PGA
Switches and Multiplexers
High-Speed, Low-Voltage, CMOS Analog Multiplexers/Switches
Not Available
Switches and Multiplexers
Low-Voltage, 60Ω, 4:1 Analog Multiplexer in QFN
Not Available
Isolation
4-Channel, 1kVRMS, and 2.75kVRMS, Digital Isolators
Isolation
4-Channel, 1kVRMS, and 2.75kVRMS, Digital Isolators
Voltage Supervisors
Single-/Dual-/Triple-Voltage µP Supervisory Circuits with Independent Watchdog Output
Not Available
Isolated Power
4.5V to 42V Input, High-Efficiency, Iso-Buck DC-DC Converter
Linear Regulators (LDOs)
200mA, Automotive, Ultra-Low Quiescent Current, Linear Regulator

Design Files (6)

Title Type Size Date
maxrefdes1154_bom PDF 113KB 2019-07-09
maxrefdes1154_test_results PDF 355KB 2019-07-09
MAXREFDES1154 - Configurable 4-Channel RTD/TC Measurement System Using the MAX11410 PDF 799KB 2019-07-09
maxrefdes1154_pcb PDF 2MB 2019-07-09
maxrefdes1154_sch PDF 55KB 2019-07-09
maxrefdes1154-firmware ZIP 7MB 2019-08-13
Date Type
2019-07-09

maxrefdes1154_bom

(PDF, 113KB)

2019-07-09

maxrefdes1154_test_results

(PDF, 355KB)

2019-07-09

MAXREFDES1154 - Configurable 4-Channel RTD/TC Measurement System Using the MAX11410

(PDF, 799KB)

2019-07-09

maxrefdes1154_pcb

(PDF, 2MB)

2019-07-09

maxrefdes1154_sch

(PDF, 55KB)

2019-08-13

maxrefdes1154-firmware

(ZIP, 7MB)

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