PTA8E16: 16-Channel PT100 Temperature Acquisition Module with RS485 Modbus RTU

PTA8E16 is a 16-channel PT100 temperature acquisition module designed for industrial temperature monitoring, multi-point data collection, and automation applications.

Supporting 2-wire and 3-wire PT100 RTD sensors, the PTA8E16 can collect temperature measurements from up to 16 independent points and transmit the data to a host controller through an RS485 interface using the Modbus RTU protocol.

With its high channel density, standard industrial communication interface, and support for both temperature and PT100 resistance readings, the PTA8E16 provides a practical solution for applications that require centralized monitoring of multiple temperature points.

It can be integrated with PLCs, industrial computers, SCADA systems, and other Modbus-compatible controllers, making it suitable for equipment manufacturers, system integrators, and industrial automation developers.

2. Key Features

16 Independent PT100 Input Channels

The PTA8E16 supports up to 16 PT100 temperature sensors through a single acquisition module. This allows users to monitor multiple locations without installing a separate temperature acquisition device for every sensor.

Typical applications include industrial equipment, heating systems, production lines, laboratories, and multi-zone temperature monitoring installations.

Two Temperature Measurement Versions

The PTA8E16 is available in two measurement-range versions:

• Version A: -40°C to +220°C

• Version B: -40°C to +500°C

Selecting the appropriate version helps users match the acquisition module to the operating temperature of their application.

For the best practical measurement performance, choose the version that covers the required temperature range without unnecessarily selecting a wider range.

Supports 2-Wire and 3-Wire PT100 Sensors

The module supports both 2-wire and 3-wire PT100 RTD connections.

Three-wire PT100 sensors are commonly used in industrial applications because suitable three-wire measurement circuits can compensate for lead resistance. Two-wire sensors may be useful in simpler installations, although their wiring resistance can contribute to measurement error.

Always follow the manufacturer's wiring diagram for the selected sensor and module.

RS485 Communication with Modbus RTU

The PTA8E16 communicates through RS485 and supports the Modbus RTU protocol.

Compatible host devices can read temperature and PT100 resistance values and configure supported parameters using standard Modbus commands.

The module supports function code 03 for reading holding registers and function codes 06 and 16 for writing supported settings.

Multiple Modules on One RS485 Network

The Modbus slave address can be changed to support multiple modules on a shared RS485 bus.

According to the published product documentation, up to 247 modules can be addressed through the configuration system. The practical number of devices on one physical bus depends on network loading, electrical characteristics, cable length, and the need for RS485 repeaters.

Flexible DC Power Supply

The PTA8E16 operates from a DC 8–30V power supply and typically consumes approximately 14–25mA.

This range supports common 12V and 24V industrial power systems.

DIN-Rail Enclosure Option

The module is available as a bare circuit board or with a DIN-rail enclosure option, making it suitable for installation inside industrial control cabinets and electrical panels.

3. Technical Specifications

Parameter	Specification
Manufacturer	Eletechsup
Model	PTA8E16
Function	16-channel PT100 temperature acquisition
Number of channels	16
Supported sensors	PT100 RTD
Sensor wiring	2-wire or 3-wire
Version A measurement range	-40°C to +220°C
Version B measurement range	-40°C to +500°C
Published measurement accuracy	1%
Communication interface	RS485
Communication protocol	Modbus RTU
Power supply	DC 8–30V
Operating current	Approximately 14–25mA
Default baud rate	9600bps
Default serial format	N, 8, 1
Read function code	03
Write function codes	06, 16
Dimensions	Approximately 136 × 92 × 32mm
Weight	Approximately 166g
Installation options	Bare board or DIN-rail enclosure

Specifications are based on Eletechsup's published product information. Confirm the latest product manual for exact register addresses, configuration commands, measurement accuracy, and enclosure dimensions.

4. How Does the PTA8E16 Work?

The PTA8E16 reads the resistance of connected PT100 sensors and converts the measurements into digital values accessible through Modbus RTU.

A typical installation follows these steps:

1. Connect the PT100 sensors to the module's input terminals, following the wiring diagram for 2-wire or 3-wire sensors.

2. Connect an appropriate DC power supply within the specified operating range.

3. Connect the RS485 A/B communication lines to a compatible PLC, industrial computer, or USB-to-RS485 adapter.

4. Configure the Modbus slave address and serial communication parameters.

5. Read the temperature or resistance registers using a Modbus master.

6. Send the collected data to a display, database, SCADA system, or temperature-control application.

For example, a manufacturing system can monitor temperatures at 16 different points on a machine and use the readings to trigger alarms or control fans, heaters, and other equipment through a separate controller.

5. GitHub Integration: Reading PTA8E16 with Python

A useful third-party software reference is the public GitHub repository ctch3ng/modbus_playground.

The repository explicitly lists the Eletechsup PTA8E16 as a supported device and includes the Python example:

pta8e16_16ch_pt100_read_loop.py

The script is designed to read temperature registers from the 16-channel PT100 acquisition module repeatedly, making it useful for testing, data collection, and software integration.

Hardware Required

A basic test setup includes:

• One Eletechsup PTA8E16 module

• Compatible PT100 sensors

• A suitable DC power supply

• A USB-to-RS485 adapter

• A computer running Python 3.9 or later

• The Python MinimalModbus library

Integration Workflow

1. Connect the PTA8E16 to the computer through the USB-to-RS485 adapter.

2. Identify the correct serial port.

3. Install Python and the required MinimalModbus library.

4. Configure the serial port, baud rate, parity, and Modbus slave address.

5. Read the temperature registers using the documented Modbus register map.

6. Repeat the read operation to collect data from all 16 channels.

The resulting data can be displayed in a terminal, stored in a CSV file, or integrated into a larger monitoring application.

GitHub example:
https://github.com/ctch3ng/modbus_playground/blob/main/pta8e16_16ch_pt100_read_loop.py

Project repository:
https://github.com/ctch3ng/modbus_playground

This third-party project demonstrates practical software integration with the PTA8E16. It is not an official Eletechsup software release, so users should verify the register addresses and serial configuration against the current product documentation before deployment.

6. Typical Applications

Industrial Equipment Temperature Monitoring

Monitor temperatures at multiple points on production machinery, electrical equipment, motors, and industrial enclosures.

Heating and Thermal Process Control

Collect temperature data from heating equipment, thermal processing systems, and industrial installations operating within the selected version's measurement range.

Battery Testing and Thermal Monitoring

Monitor temperature at multiple locations during battery testing and other thermal evaluation processes. Applications involving lithium batteries should use appropriate sensor placement, electrical protection, and independent safety controls.

HVAC and Building Automation

Measure temperatures across different zones, equipment rooms, and building systems. A PLC or building management controller can use the readings for monitoring and control.

Laboratory and Test Equipment

Collect data from multiple PT100 sensors during experiments, equipment validation, and thermal testing, provided the module's accuracy and calibration characteristics meet the requirements.

Warehouse and Environmental Monitoring

Monitor temperature at multiple locations within storage areas and general environmental monitoring installations. Regulated storage applications may require additional calibration, traceability, and system validation.

PLC and SCADA Systems

Integrate 16 temperature inputs into a centralized monitoring system using Modbus RTU over RS485.

7. Why Choose a 16-Channel PT100 Acquisition Module?

When a project requires monitoring many temperature points, using one 16-channel module can simplify wiring and reduce the number of individual acquisition devices needed.

The PTA8E16 combines 16 PT100 inputs, standard Modbus communication, two measurement-range options, and a compact industrial installation format.

It also supports reading PT100 resistance values in addition to temperature measurements, providing an additional diagnostic and data-analysis option for compatible applications.

For system integrators and equipment manufacturers, these features make the PTA8E16 a practical building block for multi-point temperature monitoring systems.

8. Installation and Design Considerations

Choose the correct measurement range. Version A covers -40°C to +220°C, while Version B covers -40°C to +500°C. Confirm that the selected range meets the actual application requirements.

Use appropriate PT100 wiring. Follow the product wiring diagram for 2-wire and 3-wire sensors. Lead resistance and wiring quality can affect measurement results.

Design the RS485 network correctly. Use suitable twisted-pair cable, proper addressing, and termination where required. Long networks or large device counts may need repeaters.

Verify measurement performance. The published 1% accuracy figure should be checked against the manufacturer's definition and the application's tolerance requirements. Sensor accuracy, wiring, calibration, and installation conditions also affect the overall result.

Test communication before commissioning. Use a USB-to-RS485 adapter and compatible Modbus software to confirm that all channels return valid measurements before connecting the module to a production control system.

Provide independent safety protection. For critical thermal processes, use appropriate independent alarms, interlocks, and protective devices rather than relying solely on software-based temperature monitoring.

9. Conclusion

The Eletechsup PTA8E16 16-Channel PT100 Temperature Acquisition Module is designed for applications that require centralized temperature measurement from multiple locations.

Its 16 sensor inputs, RS485 Modbus RTU communication, support for 2-wire and 3-wire PT100 sensors, and two temperature measurement ranges make it suitable for a wide variety of industrial monitoring and automation projects.

The availability of a third-party Python example on GitHub also gives developers a useful starting point for testing the module and integrating temperature data into their own software.

Official product page:
https://eletechsup.com/products/pta8e16-16ch-dc-12v-24v-temperature-analog-pt100-resistance-rs485-collector-modbus-rtu-40-500-high-temperature-acquisition-board

GitHub application example:
https://github.com/ctch3ng/modbus_playground/blob/main/pta8e16_16ch_pt100_read_loop.py

Eletechsup — Practical Electronic Modules for Industrial Control, Temperature Monitoring, and Automation.