{"id":1492,"date":"2026-03-10T18:18:44","date_gmt":"2026-03-10T17:18:44","guid":{"rendered":"https:\/\/eltra.bfenterprise.it\/encoder-pedia\/cose-linterfaccia-ssi\/"},"modified":"2026-04-02T11:12:38","modified_gmt":"2026-04-02T09:12:38","slug":"what-is-the-ssi-interface","status":"publish","type":"page","link":"https:\/\/eltra.bfenterprise.it\/en\/encoder-pedia\/what-is-the-ssi-interface\/","title":{"rendered":"What is the SSI interface?"},"content":{"rendered":"<p>The continuous evolution of the automation field implies a growing request for precision in measurement devices and, therefore, also in absolute encoders. To satisfy this demand, absolute encoders have been designed with always higher resolution, which means an increasing number of bits and, as a consequence, also of wires.<\/p>\n<p>The\u00a0<strong>Synchronous Serial Interface<\/strong>\u00a0(<strong>SSI<\/strong>) was created to solve these setbacks, in order to contain installation costs and simplify the wiring. This interface transmits data in a serial mode by using only two signals (<strong>CLOCK<\/strong>\u00a0and\u00a0<strong>DATA<\/strong>), independently from the number of bits of the encoder.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-493 alignnone\" src=\"https:\/\/eltra.bfenterprise.it\/wp-content\/uploads\/2026\/03\/SSI.png\" alt=\"SSI\" width=\"407\" height=\"201\" srcset=\"https:\/\/eltra.bfenterprise.it\/wp-content\/uploads\/2026\/03\/SSI.png 407w, https:\/\/eltra.bfenterprise.it\/wp-content\/uploads\/2026\/03\/SSI-300x148.png 300w\" sizes=\"auto, (max-width: 407px) 100vw, 407px\" \/><\/p>\n<p>The position data is obtained by the encoder reading system and continuously transmitted to a parallel\/serial converter (based by a \u201cshift register\u201d with parallel loading). When the mono-stable circuit is activated by a clock signal transition, the data is stored and transmitted to the output synchronized with the clock signal.<\/p>\n<p>CLOCK and DATA signals are transmitted differentially (RS422) to enhance immunity from interference and to allow longer transmission distances.<\/p>\n<p>For further information, please check the complete<a title=\"PDF SSI electronics\" href=\"https:\/\/eltra.bfenterprise.it\/wp-content\/uploads\/2026\/03\/INTERFACCIA-SSI.pdf\" target=\"_blank\" rel=\"noopener\">\u00a0PDF on-line<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The continuous evolution of the automation field implies a growing request for precision in measurement [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":721,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-1492","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/pages\/1492","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/comments?post=1492"}],"version-history":[{"count":3,"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/pages\/1492\/revisions"}],"predecessor-version":[{"id":1498,"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/pages\/1492\/revisions\/1498"}],"up":[{"embeddable":true,"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/pages\/721"}],"wp:attachment":[{"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/media?parent=1492"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}