{"id":2556,"date":"2025-04-16T05:33:16","date_gmt":"2025-04-16T05:33:16","guid":{"rendered":"https:\/\/webprojects.cloud\/wordpress\/splatco\/?post_type=spl_knowledgebase&#038;p=2556"},"modified":"2025-06-10T11:43:26","modified_gmt":"2025-06-10T11:43:26","slug":"modbusmaster","status":"publish","type":"spl_knowledgebase","link":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/programming-reference\/instructions-arranged-by-function\/hash-commands-and-functions\/open_serial-hash-command\/modbusmaster\/","title":{"rendered":"# ModBusMaster"},"content":{"rendered":"\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><th>Valid For<\/th><td>#<a href=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/programming-reference\/instructions-arranged-by-function\/hash-commands-and-functions\/open_serial-hash-command\/\">Open_Serial<\/a><\/td><\/tr><tr><th>Applies To<\/th><td>All<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>This instruction opens a serial port for use as a MODBUS Master.<\/p>\n\n\n\n<h6 class=\"wp-block-heading\">Function Prototype<\/h6>\n\n\n\n<pre class=\"wp-block-preformatted\">#Open_Serial Port(PortNumber) ModbusMaster(<br>   BaudRate,<br>   Parity,<br>   MessageGap,<br>   QueryTimeout,<br>   QueryAttempts<br> )<\/pre>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><th>Parameter<\/th><th>Option<\/th><th>Description<\/th><\/tr><tr><th>BaudRate<\/th><td>mandatory<\/td><td>The baudrate to be used. Legal values are 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 76800, 115200, (230400, 460800)*<\/td><\/tr><tr><th>Parity<\/th><td>mandatory<\/td><td>May be either:n = noneo = odde = even<\/td><\/tr><tr><th>MessageGap<\/th><td>mandatory<\/td><td>See description\u00a0<a href=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/programming-reference\/communication-control-block-elements\/message-gap-x10ms\/\">here<\/a>. Set to 0 for the default.<\/td><\/tr><tr><th>QueryTimeout<\/th><td>optional<\/td><td>Time to wait for a Modbus Slave to respond in units of 10ms.&nbsp; So 50 would be 0.5 seconds.&nbsp; Defaults to 100 (ie, 1 second)<\/td><\/tr><tr><th>QueryAttempts<\/th><td>optional<\/td><td>Number of times to re-send to a slave that isn&#8217;t responding.&nbsp; Defaults to 0 which is taken to mean no retries, just send once.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h6 class=\"wp-block-heading\">Description<\/h6>\n\n\n\n<p>This hash function sets the serial port up for use with the ModBusRTU master. Once initiated and configured, the SPLat controller&nbsp;<a href=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/glossary-of-terms\/#o370\">Firmware<\/a>&nbsp;takes care of all the low level communications activity.&nbsp;<a href=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/tutorials-application-notes-and-white-papers\/serial-communications\/modbus\/\">ModBus documentation<\/a>.<\/p>\n\n\n\n<p><strong>Port()<\/strong>&nbsp;is only available on SPLat 32 bit controllers (black boards).<\/p>\n\n\n\n<p>*The&nbsp;<strong>(high speed baud rates)<\/strong>&nbsp;are only available on SPLat 32 bit controllers (black boards).<\/p>\n\n\n\n<p>Note that 32-bit controllers allow use of Modbus on multiple ports.&nbsp; It has been successfully tried with Master mode on one port and Slave mode on another.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Valid For #Open_Serial Applies To All This instruction opens a serial port for use as a MODBUS Master. Function Prototype #Open_Serial Port(PortNumber) ModbusMaster( BaudRate, Parity,&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2555,"menu_order":0,"template":"","class_list":["post-2556","spl_knowledgebase","type-spl_knowledgebase","status-publish","hentry"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v25.6 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title># ModBusMaster - SPLat Controls<\/title>\n<meta name=\"robots\" content=\"noindex, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"# ModBusMaster - SPLat Controls\" \/>\n<meta property=\"og:description\" content=\"Valid For #Open_Serial Applies To All This instruction opens a serial port for use as a MODBUS Master. 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