{"id":2133,"date":"2025-04-15T06:13:40","date_gmt":"2025-04-15T06:13:40","guid":{"rendered":"https:\/\/webprojects.cloud\/wordpress\/splatco\/?post_type=spl_knowledgebase&#038;p=2133"},"modified":"2025-06-10T09:40:42","modified_gmt":"2025-06-10T09:40:42","slug":"oblcd-modbus-interaction","status":"publish","type":"spl_knowledgebase","link":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/","title":{"rendered":"OBLCD: ModBus interaction"},"content":{"rendered":"\n<p>Standard controllers with dialect 21 or later are able to have their OBLCD information transferred to other devices via ModBus. In dialect 21 this is possible only when the SPLat controller is the ModBus slave. It is however possible with all standard controllers, CC18, MS120, MMi202 and SL100. That means that even those controllers that cannot support an OnBoard LCD device (hardware) can use OBLCD instructions to display messages on an external, 3rd party, display &#8211; providing that display can be a ModBus RTU master.<\/p>\n\n\n\n<p>The OBLCD logical device in a SPLat controller contains an area of memory of up to 80 bytes. The size depends on the&nbsp;<code><a href=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-programming\/oblcd-initializing-the-lcd\/oblcd_type-tt\/\">OBLCD_Type<\/a><\/code>. When an external ModBus master addresses a special range of memory within the SPLat, it accesses that buffer (See&nbsp;<a href=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/programming-reference\/instructions-arranged-by-function\/communications-instructions\/modbus-instructions\/modbus-resource-mapping\/\">ModBus: Resource mapping<\/a>&nbsp;for actual addresses). Hence the external device can extract the LCD buffer and (presumably) display it on its own display (for example a touch screen&nbsp;<a href=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/glossary-of-terms\/#o5243\">HMI<\/a>).<\/p>\n\n\n\n<p>The data found in the OBLCD buffer is the same data that has been sent there by the SPLat program. This has consequences for special characters such as degree signs. The regular LCD modules do not use ASCII codes for such characters. This is reflected in the\u00a0<a href=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-special-characters\/\">OBLCD: Special characters<\/a>. 3rd party HMIs are more likely to use standard ASCII codes, and will give strange results with OBLCD special character codes.<\/p>\n\n\n\n<p>For a given OBLCD_Type, the displayed characters occupy consecutive locations in the buffer. For example, for a 2&#215;16 display (type 2), they occupy the first 32 bytes of the buffer. For a 4&#215;20 display (type 5) they use the whole buffer. The buffer contents outside the display type defined by&nbsp;<code>OBLCD_Type <\/code>is unpredictable.<\/p>\n\n\n\n<p>If you are using a SPLat&nbsp;<a href=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/glossary-of-terms\/#o372\">Controller<\/a>&nbsp;with an LCD, say an MS120, it can get interesting, particularly if you set the&nbsp;<code>OBLCD_Type<\/code>&nbsp;to a different type. Say you have a 2&#215;16 display but set&nbsp;<code>OBLCD_Type<\/code>&nbsp;to 5 (4&#215;20). The actual onboard display will show the first 16 characters of the first two lines of the display buffer. The whole display buffer will be accessible by an external HMI.<\/p>\n\n\n\n<p>Note that the OBLCD buffer also appears at Xwire address 249 as described in the\u00a0<a href=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/programming-reference\/instructions-arranged-by-function\/onboard-lcd-oblcd-instructions\/xwire-oblcd\/\">Xwire OBLCD page<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Standard controllers with dialect 21 or later are able to have their OBLCD information transferred to other devices via ModBus. In dialect 21 this is&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2076,"menu_order":5,"template":"","class_list":["post-2133","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>OBLCD: ModBus interaction - 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=\"OBLCD: ModBus interaction - SPLat Controls\" \/>\n<meta property=\"og:description\" content=\"Standard controllers with dialect 21 or later are able to have their OBLCD information transferred to other devices via ModBus. In dialect 21 this is...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/\" \/>\n<meta property=\"og:site_name\" content=\"SPLat Controls\" \/>\n<meta property=\"article:modified_time\" content=\"2025-06-10T09:40:42+00:00\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/\",\"url\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/\",\"name\":\"OBLCD: ModBus interaction - SPLat Controls\",\"isPartOf\":{\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/#website\"},\"datePublished\":\"2025-04-15T06:13:40+00:00\",\"dateModified\":\"2025-06-10T09:40:42+00:00\",\"breadcrumb\":{\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Product documentation\",\"item\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"Product documentation: Onboard peripherals\",\"item\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/\"},{\"@type\":\"ListItem\",\"position\":4,\"name\":\"Onboard LCD\",\"item\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/\"},{\"@type\":\"ListItem\",\"position\":5,\"name\":\"OBLCD: ModBus interaction\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/#website\",\"url\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/\",\"name\":\"SPLat Controls\",\"description\":\"OEM Embedded Machine Controllers\",\"publisher\":{\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/#organization\",\"name\":\"SPLat Controls\",\"url\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2024\/10\/logo.svg\",\"contentUrl\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2024\/10\/logo.svg\",\"caption\":\"SPLat Controls\"},\"image\":{\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/#\/schema\/logo\/image\/\"}}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"OBLCD: ModBus interaction - SPLat Controls","robots":{"index":"noindex","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"og_locale":"en_US","og_type":"article","og_title":"OBLCD: ModBus interaction - SPLat Controls","og_description":"Standard controllers with dialect 21 or later are able to have their OBLCD information transferred to other devices via ModBus. In dialect 21 this is...","og_url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/","og_site_name":"SPLat Controls","article_modified_time":"2025-06-10T09:40:42+00:00","twitter_card":"summary_large_image","twitter_misc":{"Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/","url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/","name":"OBLCD: ModBus interaction - SPLat Controls","isPartOf":{"@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/#website"},"datePublished":"2025-04-15T06:13:40+00:00","dateModified":"2025-06-10T09:40:42+00:00","breadcrumb":{"@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/oblcd-modbus-interaction\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/webprojects.cloud\/wordpress\/splatco\/"},{"@type":"ListItem","position":2,"name":"Product documentation","item":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/"},{"@type":"ListItem","position":3,"name":"Product documentation: Onboard peripherals","item":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/"},{"@type":"ListItem","position":4,"name":"Onboard LCD","item":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/product-documentation\/product-documentation-onboard-peripherals\/onboard-lcd\/"},{"@type":"ListItem","position":5,"name":"OBLCD: ModBus interaction"}]},{"@type":"WebSite","@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/#website","url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/","name":"SPLat Controls","description":"OEM Embedded Machine Controllers","publisher":{"@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/webprojects.cloud\/wordpress\/splatco\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/#organization","name":"SPLat Controls","url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/#\/schema\/logo\/image\/","url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2024\/10\/logo.svg","contentUrl":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2024\/10\/logo.svg","caption":"SPLat Controls"},"image":{"@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/#\/schema\/logo\/image\/"}}]}},"_links":{"self":[{"href":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-json\/wp\/v2\/spl_knowledgebase\/2133","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-json\/wp\/v2\/spl_knowledgebase"}],"about":[{"href":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-json\/wp\/v2\/types\/spl_knowledgebase"}],"author":[{"embeddable":true,"href":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-json\/wp\/v2\/users\/1"}],"up":[{"embeddable":true,"href":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-json\/wp\/v2\/spl_knowledgebase\/2076"}],"wp:attachment":[{"href":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-json\/wp\/v2\/media?parent=2133"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}