diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Uns/TagEditors/S7TagConfigModel.cs b/src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Uns/TagEditors/S7TagConfigModel.cs
index 1692f39a..3e944d4a 100644
--- a/src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Uns/TagEditors/S7TagConfigModel.cs
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Uns/TagEditors/S7TagConfigModel.cs
@@ -112,6 +112,26 @@ public sealed class S7TagConfigModel
                 + string.Join(", ", Enum.GetNames<S7DataType>()) + ".";
         }
 
+        // S7-016: array shape is judged against the driver's INIT guards, which THROW (failing the whole
+        // driver's init, not just this tag) for a wide-type array and for a writable Bool array. The
+        // isArray / arrayLength keys themselves belong to the TagModal's generic array controls
+        // (TagArrayConfig) and are intentionally not fields of this model, so read them off the key bag.
+        if (TagConfigJson.GetBool(_bag, "isArray"))
+        {
+            var dt = DataType;
+            if (dt is S7DataType.Int64 or S7DataType.UInt64 or S7DataType.Float64
+                   or S7DataType.String or S7DataType.DateTime)
+            {
+                return $"S7 does not support {dt} arrays — use Bool (read-only), Byte, Int16, UInt16, Int32, "
+                    + "UInt32 or Float32 for an array tag, or a scalar tag.";
+            }
+            if (dt == S7DataType.Bool && (Writable ?? true))
+            {
+                return "A Bool array cannot be writable (a byte-granular write would clobber neighbouring bits) — "
+                    + "uncheck Writable, or use scalar Bool tags.";
+            }
+        }
+
         // Gitea #554: the reader's remaining, non-enum refusal — a String tag whose 'stringLength' is
         // negative or above 254 (S7 REJECTS it rather than clamping) — is not restated here. The verdict and
         // the wording both come from the driver's own reader, via TagConfigParseGate.
diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/Uns/S7TagConfigModelTests.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/Uns/S7TagConfigModelTests.cs
index dbbccfa4..5152626c 100644
--- a/tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/Uns/S7TagConfigModelTests.cs
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/Uns/S7TagConfigModelTests.cs
@@ -103,4 +103,44 @@ public sealed class S7TagConfigModelTests
     [InlineData("""{"address":"DB1.DBW0","dataType":7}""")]
     public void Validate_accepts_every_dataType_the_driver_accepts(string json)
         => S7TagConfigModel.FromJson(json).Validate().ShouldBeNull();
+
+    // ---- S7-016: array shape vs the driver's init guards (which fail the WHOLE driver init) ----
+
+    [Theory]
+    [InlineData("Int64")]
+    [InlineData("UInt64")]
+    [InlineData("Float64")]
+    [InlineData("String")]
+    [InlineData("DateTime")]
+    public void Validate_rejects_wide_type_arrays(string dataType)
+    {
+        var m = S7TagConfigModel.FromJson(
+            $$"""{"address":"DB1.DBB0","dataType":"{{dataType}}","isArray":true,"arrayLength":4,"writable":false}""");
+
+        m.Validate().ShouldNotBeNull().ShouldContain("arrays");
+    }
+
+    [Fact]
+    public void Validate_rejects_a_writable_bool_array_but_accepts_it_read_only()
+    {
+        var writable = S7TagConfigModel.FromJson(
+            """{"address":"DB1.DBX0.0","dataType":"Bool","isArray":true,"arrayLength":4}""");
+        writable.Validate().ShouldNotBeNull().ShouldContain("Bool array");
+
+        var readOnly = S7TagConfigModel.FromJson(
+            """{"address":"DB1.DBX0.0","dataType":"Bool","isArray":true,"arrayLength":4,"writable":false}""");
+        readOnly.Validate().ShouldBeNull();
+    }
+
+    [Theory]
+    [InlineData("Byte", "DB1.DBB0")]
+    [InlineData("Int16", "DB1.DBW0")]
+    [InlineData("Float32", "DB1.DBD0")]
+    public void Validate_accepts_writable_arrays_of_supported_element_types(string dataType, string address)
+    {
+        var m = S7TagConfigModel.FromJson(
+            $$"""{"address":"{{address}}","dataType":"{{dataType}}","isArray":true,"arrayLength":4}""");
+
+        m.Validate().ShouldBeNull();
+    }
 }