[PC-1788] Digital Expansion Output Mapping Tabled User Manual (#2026)

* Output mapping table added

* Small format improvement for the new table

---------

Co-authored-by: jcarolinares <[email protected]>

Author: mcmchris

content/hardware/07.opta/opta-family/opta/tutorials/01.user-manual/content.md

@@ -2211,6 +2211,20 @@ The Opta™ Expansions have **8 relay outputs** accessible through terminals pai
 
 ![Opta Digital Expansions outputs](assets/variants-emr-ssr-new.png)
 
+Relay Output terminals are mapped as described in the following table:
+
+| **Opta Digital Expansion Terminal** | **Arduino Pin Mapping** |
+| :---------------------------------: | :---------------------: |
+|               Relay 1               |            0            |
+|               Relay 2               |            1            |
+|               Relay 3               |            2            |
+|               Relay 4               |            3            |
+|               Relay 5               |            4            |
+|               Relay 6               |            5            |
+|               Relay 7               |            6            |
+|               Relay 8               |            7            |
+
+
 The **Ext D1608E (EMR)** variant features 8 electromechanical relays with the following characteristics:
 
 <table>