{"product_id":"rtd-data-acquisition-8-layer-stackable-hat-for-raspberry-pi-discontinued","title":"RTD Data Acquisition 8-Layer Stackable HAT for Raspberry Pi [Discontinued]","description":"\u003cp\u003eThe RTD Data Acquisition Card offers a compact and inexpensive solution for reading and storing data from up to 64 RTD-100 temperature sensors with a Raspberry Pi.\u003c\/p\u003e\n\u003cp\u003eUsing two ADS1248 24-bit delta-sigma converters with four channels each, the card achieves better than 0.1%. Field calibration with a precision 100Ω resistor can lead to 0.01% precision.\u003c\/p\u003e\n\u003cp\u003eSince 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.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePlease note the board layout may change slightly between batches (such as the pin jumper headers).\u003c\/strong\u003e If your project or design is reliant on the positioning of pins and other parts, please contact us first and we'll be happy to send images of the current batch.\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eFor any technical questions about this product please email \u003c\/span\u003esupport@sequentmicrosystems.com\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eNote\u003c\/strong\u003e: Raspberry Pi is \u003cstrong\u003eNOT\u003c\/strong\u003e included\u003c\/p\u003e\n\u003ch2\u003eRevision History\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eThe RTD card now has an RS485 transceiver, works with PT100 sensors, and has programmable LEDs indicating the status of all inputs.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eFeatures\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eRTD Data Acquisition 8-Layer Stackable HAT for Raspberry Pi\u003c\/li\u003e\n\u003cli\u003e24-bit delta-sigma A\/D converters\u003c\/li\u003e\n\u003cli\u003eFactory accuracy: 0.1%\u003c\/li\u003e\n\u003cli\u003eMaximum accuracy (through calibration): 0.01%\u003c\/li\u003e\n\u003cli\u003eMaximum acquisition speed 40 cps\u003c\/li\u003e\n\u003cli\u003eEight layers stackable to 64 RTD channels\u003c\/li\u003e\n\u003cli\u003eRS485\/MODBUS transceiver\u003c\/li\u003e\n\u003cli\u003ePT100 sensors. PT1000 available for special orders\u003c\/li\u003e\n\u003cli\u003eProgrammable threshold LEDs on all inputs\u003c\/li\u003e\n\u003cli\u003ePluggable Connectors 26-16 AWG wires\u003c\/li\u003e\n\u003cli\u003eOn-board hardware watchdog able to power cycle the Raspberry Pi\u003c\/li\u003e\n\u003cli\u003eReverse polarity power supply protection\u003c\/li\u003e\n\u003cli\u003eGeneral Purpose Pushbutton\u003c\/li\u003e\n\u003cli\u003eOn-board resettable fuse\u003c\/li\u003e\n\u003cli\u003eRTD DAQ Raspberry Pi\u003c\/li\u003e\n\u003cli\u003eCommand line \u003c\/li\u003e\n\u003cli\u003ePython library\u003c\/li\u003e\n\u003cli\u003eNode-Red nodes\u003c\/li\u003e\n\u003cli\u003eModbus RTU\u003c\/li\u003e\n\u003cli\u003e\nOpenPLC\u003cspan\u003e \u003c\/span\u003emodule\u003c\/li\u003e\n\u003cli\u003eArduino Library\u003c\/li\u003e\n\u003cli\u003eOptional -50°C to 450°C PT100 sensors\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eFeature Details\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eCompatability\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe card is compatible with all 40-pin Raspberry Pi versions from Zero to 4. It shares the I2C bus using only two of the Raspberry Pi’s GPIO pins to manage all eight cards.\u003c\/p\u003e\n\u003cp\u003eThis feature leaves the remaining 24 GPIOs available for the user.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePower Requirements\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe RTD Data Acquisition card needs 5V to operate and can be powered from the Raspberry Pi. The cards require 50mA to operate.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cstrong\u003eStacking Multiple Cards\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eUp to eight RTD Data Acquisition cards can be stacked on your Raspberry Pi.\u003c\/p\u003e\n\u003cp\u003eEach card is identified by jumpers you install to indicate the level in the stack. Cards can be installed in any order. For your convenience, two stack jumpers are provided with each card.\u003cbr data-mce-fragment=\"1\"\u003e\u003cimg data-mce-fragment=\"1\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0176\/3274\/files\/stack_level2_600x600.jpg?v=1620935950\" alt=\"rtd card stacking pins\" data-mce-src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0176\/3274\/files\/stack_level2.jpg?v=1620935950\u0026amp;width=700\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cstrong\u003eDIN-Rail Mounting\u003c\/strong\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eThe RTD Data Acquisition card can be installed parallel on a DIN-Rail using the DIN-Rail Kit Type 1, or perpendicular using the DIN-Rail Kit Type 2.\u003cbr data-mce-fragment=\"1\"\u003e\u003c\/p\u003e\n\u003ch2\u003eSoftware\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eSoftware Interfaces\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYou 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.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eField Calibration\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eField 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).\u003c\/p\u003e\n\u003cp\u003eThe resulting values are stored in flash and used for resistance measurements compensation witch will reflect in the temperature readings.\u003c\/p\u003e\n\u003cp\u003eThe 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) and k= 0.00385. If the user needs to use the polynomial equation, the resistance measurements are available.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eRS485\/MODBUS Communication\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 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 configuration connector J3.\u003c\/p\u003e\n\u003cp\u003eSee in the card layout section below 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 that 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:\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e~$ rtd [0] rs485wr 0 0 0 0 0\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eIf 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.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003eIn 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.\u003cbr data-mce-fragment=\"1\"\u003e\u003cbr data-mce-fragment=\"1\"\u003e\u003cstrong\u003eLED Threshold Signals\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe RTD board has eight LEDs that can be activated when the input reaches a preset threshold. The threshold can be set in software for each input.\u003cbr data-mce-fragment=\"1\"\u003e\u003cstrong\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFirmware Update\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 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.\u003c\/p\u003e\n\u003cp\u003ePlease make sure there is no process, like Node-Red or python scripts, that tries to access the card during the update process.\u003c\/p\u003e\n\u003ch2\u003eCard Layout\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eNote\u003c\/strong\u003e: the PT100\/1000 2-pin jumpers have been removed due to the \u003cspan data-mce-fragment=\"1\"\u003edisappearance of the ADS1248 A\/D converter from the marketplace. Board layout\/connectors vary slightly by batch\u003c\/span\u003e\u003cbr\u003e\u003cimg data-mce-fragment=\"1\" alt=\"RTD card layout\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0176\/3274\/files\/RTD_layout1_600x600.jpg?v=1621417112\" data-mce-src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0176\/3274\/files\/RTD_layout1.jpg?v=1621417112\u0026amp;width=700\"\u003e\u003c\/p\u003e\n\u003ch2\u003ePackage Contents\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e1x RTD Data Acquisition Card\u003c\/li\u003e\n\u003cli\u003e4x M2.5x18mm male-female brass standoffs\u003c\/li\u003e\n\u003cli\u003e4x M2.5x5mm brass screws\u003c\/li\u003e\n\u003cli\u003e4x M2.5 brass nuts\u003c\/li\u003e\n\u003cli\u003e2x Pin Jumpers\u003c\/li\u003e\n\u003cli\u003e8x 3-pin mating connector plugs\u003c\/li\u003e\n\u003cli\u003e2x 2-pin \u003cspan data-mce-fragment=\"1\"\u003emating connector plugs\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eMechanical Specifications\u003cbr\u003e\n\u003c\/h2\u003e\n\u003cp\u003e\u003cimg alt=\"RTD card mechanical layout\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0176\/3274\/files\/ModularIndustrial-Mech.jpg?v=1635855834\u0026amp;width=700\"\u003e\u003c\/p\u003e","brand":"Sequent","offers":[{"title":"Default Title","offer_id":55919680847945,"sku":"lme1787258037161","price":50.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0937\/7185\/7993\/files\/rtd-data-acquisition-8-layer-stackable-hat-for-raspberry-pi-discontinued_1.jpg?v=1787258041","url":"https:\/\/streetclad.shop\/products\/rtd-data-acquisition-8-layer-stackable-hat-for-raspberry-pi-discontinued","provider":"My Store","version":"1.0","type":"link"}