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--- how_tos:serial_port_programming [2018/09/04 12:45]
jeff Images renamed
+++ how_tos:serial_port_programming [2021/09/13 05:57]
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-======Serial Port Programming======
-WattmonPRO comes with an RS-232 serial interface on pins 7 and 8 and an RS-485 port on an RJ45 connector.  The device is configured by default for RS-232 voltage levels and by using a simple DB9 cable can be connected to any serial device.  For specific devices that require TTL levels, a jumper setting inside the device can bypass the level converter IC and it can thus be used to interface with sensors or other devices at 3.3V DC.
-=====Using the RS-232 Serial Port=====
-To open the serial port, use the [[uphp:functions:fseropen()]] function.
-The serial port is treated like a file after opening and standard file functions such as [[uphp:functions:fread()]], [[uphp:functions:fwrite()]], [[uphp:functions:fgets()]] and [[uphp:functions:filesize()]] apply.
-An example of using the serial port is shown below:
-<code php>
-<?
-  // Open the serial port at 115200 baud in non-blocking mode
-  $fp=fseropen(115200,0);
-  if (!$fp) {
-    print("Serial open failed");
-  } else {
-    $res=fwrite($fp,"Hello from wattmon");
-    if ($res) {
-      print("An error occurred while trying to write to the port");
-    }
-    fclose($fp);
-  }
-?>
-</code>
-====Jumper Settings Inside Wattmon====
-{{20170318_rs232_mode.png?250|Settings for RS-232 Mode}} < //Settings for RS-232 Mode   //{{20170318_ttl_mode.png?250|Settings for TTL Mode}} < //Settings for TTL Mode//
-====RS-232 Cable Connection====
-In order to connect to a device you will need to procure a DB9 cable (male or female) and connect it up as shown in the following diagram:
-{{20170318_wattmonpro_rs232.png?300|RS-232 DB9 Connection to Wattmon}}
-=====Using the RS-485 Serial Port=====
-In order to use the RS-485 port, you need to disable modbus polling.  This is done from the Devices > Options > Edit Communication Settings as shown here:
-{{20170318_modbus_polling_setting.png?600|Disable Modbus Polling}}
-To open the RS-485 port, use the [[uphp:functions:f485open()]] function.
-The RS-485 serial port is treated like a file after opening and standard file functions such as [[uphp:functions:fread()]], [[uphp:functions:fwrite()]], [[uphp:functions:fgets()]] and [[uphp:functions:filesize()]] apply.
-An example of using the RS-485 serial port is shown below:
-<code php>
-<?
-  // Open the 485 port at 115200 baud with no parity
-  $fp=f485open(115200,0);
-  if (!$fp) {
-    print("Serial open failed");
-  } else {
-    $res=fwrite($fp,"Hello from wattmon");
-    if ($res) {
-      print("An error occurred while trying to write to the port");
-    }
-    fclose($fp);
-  }
-?>
-</code>
-====RS-485 Cable Connection====
-Use a standard RJ-45 cable and cut it to connect your RS-485 device to WattmonPRO.
-^ PIN      ^ Color      ^ Description    ^
-| 1,2      | Orange     | GND            |
-| 4        | Blue       | D+ / A         |
-| 5        | White-Blue | D- / B         |
-{{20170318_rj45_connector_pinout.png?450|RJ45 Connection Pinout}}

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