Hi Shou, 

Scheduled Control Plans shows already scheduled Analysis only , in order to schedule Inventory analysis 

Generate Sample Frequency Schedule

Explanation

Use this activity to generate a schedule for creating inventory analyses.

Prerequisites

• A control plan inventory header and one or more control plan lines for that header must exist. 
• The control plan must be in the Active status. 

System Effects

• A schedule for generating inventory analyses is created.
• Analyses will be created automatically as defined by the sample frequency schedule. 

Window

Control Plan - Inventory
Control Plans

Related Window Descriptions

Control Plan - Inventory
Control Plans 
Schedule sample frequency

Procedure

1. Query for the Control Plan Inventory for which you want to generate a schedule in the Control Plan - Inventory window.
2. Choose Schedule Sample Frequency from the right mouse button menu. The Schedule Sample Frequency dialog box appears.
3. Enter a start and end date in the Period group box.
4. Choose when you want to create the analysis in the Frequency group box.
5. If you choose Monthly, the analysis is created on its start date every month.
6. If you choose Weekly, you can also choose the days of the week on which you want the analysis to be created in the Repeated Frequency group box.
7. If you choose Daily, you can enter a number indicating how often you want to generate the analysis. For example, 2 creates an analysis every two days.  If you enter 7, 14, 21, or 28 (or any number that is a multiple of 7), you can also choose which days of the week in the Repeated Frequency group box.
8. If you choose Annually, the analysis is created once every year.
9. Click Schedule when you are finished.
10. You can now view your schedule in the Scheduled Inventory Control Plans window.

You can do it as above , But I doubt this really serves the purpose.