RTD Data Acquisition 8-layer stackable HAT V7.0 for Raspberry Pi with 8 RTD sensor inputs, RS485 communication, and software-selectable PT100/PT1000 support.

RTD Data Acquisition 8-channel stackable HAT for Raspberry Pi with RS485, PT100/PT1000 sensor support, and software-configurable inputs.

RTD Data Acquisition 8-layer stackable HAT mounted on Raspberry Pi with green connectors and red DIP switch for temperature sensor data collection

RTD Data Acquisition 8-layer stackable HAT for Raspberry Pi with multiple sensor inputs and RS485 communication

RTD Data Acquisition 8-layer stackable HAT for Raspberry Pi with 24-bit A/D converters and PT100/PT1000 sensor support

RTD Data Acquisition 8-layer stackable HAT circuit board for Raspberry Pi with 24-bit delta-sigma A/D converters and sensor support.

RTD Data Acquisition 8-layer stackable HAT 360 view

SKU: SM-I-004

RTD Data Acquisition 8-Layer Stackable HAT for Raspberry Pi

Name: RTD Data Acquisition 8-Layer Stackable HAT for Raspberry Pi
Brand: Sequent Microsystems
SKU: SM-I-004
Price: 80.0 USD
Availability: InStock

Eight Channel RTD Data Aquisition HAT; 0.01% accuracy through calibration; PT100/1000 Sensors; RS485/MODBUS, Watchdog.

In stock

$80.00

Product variants

The RTD interface card supports both PT100 and PT1000 RTD sensors and delivers accurate, stable data for industrial monitoring, environmental sensing, and scientific applications. With robust hardware and straightforward software support, it turns your Raspberry Pi into a reliable temperature acquisition system ready for demanding real-world deployments. Add up to eight PT100 RTD sensors to your board.

FEATURES

NEW: V7 supports both PT100 and PT1000 sensors
NEW: Sensor selection in software. No jumpers!
NEW: 5A current transfer for Raspberry Pi 5
24 bit delta-sigma A/D converters
Factory accuracy: 0.1%
Maximum accuracy (through calibration): 0.01%
Maximum acquisition speed 40 cps
Eight layer stackable to 64 RTD channels
RS485/MODBUS transceiver
PT100 sensors, -200°C to 765°C range
PT1000 sensors, -50°C to 500°C range
Programmable threshold LEDs on all inputs
Pluggable Connectors 26-16 AWG wires
On-board hardware watchdog able to power cycle the Raspberry Pi
5V power supply provides power to Raspberry Pi
General Purpose Pushbutton
On-board resettable fuse
RTD Data Acquisition for Raspberry Pi
Uses only I2C port, all GPIO pins available
Works with any Raspberry Pi from ZERO to 5
ECCN Code EAR99
Command line
Python library
Node-Red nodes
Modbus RTU
CODESYS Driver
OpenPLC module
Arduino Library
Home Assistant Integration

The Revision 7 of the RTD card has an RS485 transceiver, works with PT100 and PT1000 sensors, and has programmable LEDs indicating the status of all inputs.

DESCRIPTION

Compatible with all Raspberry Pi versions from Zero to 5, the RTD Data Acquisition Card offers a compact and inexpensive solution for reading and storing data from up to 64 PT100 or PT1000 temperature sensors. Using 24 bit delta-sigma A/D converters with four channels each, the card achieves better than 0.1% accuracy. Field calibration with a precision 100Ω resistor can lead to 0.01% precision.

Since temperature measurement using RTD is based on resistance, the resistance in the lead wires and connectors must be taken into account when calculating the overall resistance in the system circuit. Using a 3-wire circuit design allows lead wire resistance to be factored out of the overall calculation.

COMPATIBILITY
The card is compatible with all Raspberry Pi versions from Zero to 5. It shares the I2C bus using only two of the Raspberry Pi’s GPIO pins to manage all eight cards. This feature leaves the remaining 24 GPIOs available for the user.

POWER REQUIREMENTS

The card needs 5V to operate and can be powered from Raspberry Pi or from it's own pluggable connector. The cards needs 50mA to operate.

STACKING MULTIPLE CARDS

Up to eight RTD Data Acquisition cards can be stacked on your Raspberry Pi. Three positions of the configuration DIP Switch labeled ID0, ID1, ID2 are used to select the stack level. Cards can be stacked in any order.

BOARD LAYOUT

ELECTRICAL SPECIFICATIONS

MECHANICAL SPECIFICATIONS

SOFTWARE

SOFTWARE INTERFACES

You can write your own Data Acquisition system in C, C++, PERL or the language of your choice using the Command Line functions or the Python Library. A browser interface can easily be deployed using Node-Red.

FIELD CALIBRATION

Field calibration to 0.01% precision can be achieved using an external high precision resistor. Software commands permit the user to calibrate the card in two points (the 2 points must be as far as possible but inside the measurement range). The resulting values are stored in flash and used for resistance measurements compensation witch will reflect in the temperature readings. The resistance to temperature conversion is made by the simplest equation T = (R - R0)/(R0*k), where T is temperature in Celsius degree; R is the sensor resistance; R0 is the resistance at 0 deg Celsius (100 for PT100, 1000 for PT100) and k= 0.00385. If the user need to use the polynomial equation, the resistance measurements are available.

RS485/MODBUS Communication

The RTD Data Acquisition card contains a standard RS485 transceiver which can be accessed by the local processor or by Raspberry Pi. The desired configuration is set from two bypass jumpers on the configuration connector J3. See in the CARD LAYOUT jumpers "485-RX" and "485-TX". If jumpers are installed, Raspberry Pi can communicate with any device with an RS485 interface. In this configuration the card is a passive bridge which implements only the hardware levels required by the RS485 protocol. To use this configuration, you need to tell the local processor to release control of the RS485 bus:

~$ rtd [0] rs485wr 0 0 0 0 0

If jumpers are removed, the card operates as MODBUS slave and implements the MODBUS RTU protocol. Any MODBUS master can access all the card's inputs, and set all the outputs using standard MODBUS commands. A detailed list of commands implemented and parameters addresses can be found on GitHub:

In both configurations the local processor needs to be programmed to release (jumpers installed) or control (jumpers removed) the RS485 signals. See the command line online help for further information.

LED threshold signals

The RTD Data Acquisition card has eight LEDs that can be activated when the input reaches a preset threshold. The threshold can be set in software for each input.

FIRMWARE UPDATE

The card firmware can be updated in the field by running a command. The update is made with the latest firmware version located on our servers. More instructions about the process can be found on GitHub. Please make sure there is no process, like Node-Red or python scripts, that tries to access the card during the update process.