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How to create a web server to read a SD card with our Ethernet PLC's

Introducción

In this example we see how to read a SD card into the PLC through Ethernet connection. We will show how to create a server that when there is a request through a browser, you will see the directories and the files of the SD card.

Siga this post para asegurar una buena conexión de la tarjeta SD en el PLC Ethernet!


Requisitos

Ethernet PLC:           MDuino Family Products


Arduino SD Library:    Arduino SD Library


Software

Once all is connected correctly, the next step is to make the right configuration of the Ethernet port and create the server:

/*
   Copyright (c) 2017 Boot&Work Corp., S.L. All rights reserved

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU Lesser General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <SD.h> #include <Ethernet2.h> #define SD_SS_PIN 53 File root; // Enter a MAC address for your controller below. // Newer Ethernet shields have a MAC address printed on a sticker on the shield byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; EthernetServer server(80); ///////////////////////////////////////////////////////////////////////////////// void setup() { Serial.begin(115200L); // Init Ethernet and TCP server Serial.println("Starting Ethernet ..."); Ethernet.begin(mac); server.begin(); // Init SD card Serial.println("Starting SD card ..."); if (!SD.begin(SD_SS_PIN)) { Serial.println("initialization failed!"); return; } Serial.print("IP address: "); Serial.println(Ethernet.localIP()); } /////////////////////////////////////////////////////////////////////////////// void loop() { EthernetClient client = server.available(); if (client) { char lastC = 0; while (client.connected()) { if (client.available()) { char c = client.read(); if ((c == '\n') && (lastC == '\n')) { client.println("HTTP/1.1 200 OK"); client.println("Content-Type: text/plain"); client.println("Connection: close"); client.println(); client.println("SD card files:"); root = SD.open("/"); printDirectory(root, client); break; } if (c != '\r') { lastC = c; } } } delay(50); client.stop(); } } //////////////////////////////////////////////////////////////////////////////// void printDirectory(File dir, Stream &stream) { while (true) { File entry = dir.openNextFile(); if (!entry) { // no more files break; } stream.print(entry.name()); if (entry.isDirectory()) { stream.println("/"); } else { // files have sizes, directories do not stream.print(" ["); stream.print(entry.size(), DEC); stream.println("]"); } entry.close(); } }

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