<Causes>

1. No data is stored in the device memory address for each graph number.
2. The number of points to display is not specified in the control device memory.

<Solutions>

1. Check if data is stored in as many memory addresses as specified for [Points to Display] starting from the memory address specified for [Device] for each graph number.
   
   Example: [Points to Display]: 100, [Device] for graph No. 0: WM0     
                  Store data in WM0 to WM99.
   
   
   
   
2. Check if the number of points to display (1 to 1920) is stored in bit 0 to bit 10 of the control memory.
   
   Example: [Control Device]: WM5000, number of points to display: 100
                   Specify the number of points to display (100) in bit 0 to bit 10 of WM5000.
   
   
   * For more information about [Control Device] and [Points to Display] for trend graphs, click here.