The causes are listed below.

<Causes>

1. The screen number to display is not specified in read area "n + 2".
2. The specified screen number is the same as the previous screen number.

<Solutions>

1. Check the value specified in read area "n + 2".
   The value must be specified in the data format (DEC/BCD) as set in the screen data.
   The set data format can be viewed in the following location.
   
   

     * For details about how to check Read area, click here.
   
   

   V8/TS series
   Setting location: V-SFT-6 editor [System Setting] → [Hardware Setting] →
                             [PLCx Properties]→ [Communication Setting] → [Code]

    

   V7 series
   Setting location: V-SFT-5 editor [System Setting] → [PLC Communication] →
                             [Communication Parameter] → [Detail] → [Code]

    

2. Bit 14 (screen forced switching) of read area "n + 1" must be OFF → ON (leading edge).

Example: Read area "n + 2" (D2)

Step a: Change to screen No. 5 according to read area "n + 2"
Step b: Change to screen No. 2 with an internal switch
Step c: Change to the same screen number as step a (screen No. 5) according to read area "n + 2"

In this case, however, the same value is stored in read area "n + 2" so the command is not valid.
In such a case, it is possible to forcibly switch the screen to the screen number contained in read area "n + 2" at the leading edge [0 → 1] of bit 14 of read area "n + 1" (D1).