diff --git a/source/_components/ness_alarm.markdown b/source/_components/ness_alarm.markdown
index 74d7d727aa1..9a3f36dbf7a 100644
--- a/source/_components/ness_alarm.markdown
+++ b/source/_components/ness_alarm.markdown
@@ -59,6 +59,11 @@ port:
   description: The port on which the IP232 module listens for clients.
   required: true
   type: integer
+scan_interval:
+  description: "Time interval between updates. Supported formats: `scan_interval: 'HH:MM:SS'`, `scan_interval: 'HH:MM'` and Time period dictionary (see example below)."
+  required: false
+  default: '00:01:00'
+  type: time
 zones:
   description: List of zones to add
   required: false
@@ -79,6 +84,18 @@ zones:
       type: string
 {% endconfiguration %}
 
+#### {% linkable_title Time period dictionary example %}
+
+```yaml
+scan_interval:
+  # At least one of these must be specified:
+  days: 0
+  hours: 0
+  minutes: 0
+  seconds: 10
+  milliseconds: 0
+```
+
 ## {% linkable_title Services %}
 
 ### {% linkable_title Service `aux` %}