Chapter 3 Creating and Editing Screens Note: Checking of Auto reset flags will reset the control block flags (Bits) automatically after the desired procedure has been executed. If this box is not checked, the system will ask the user to reset the flags. 3.4.1 Control Block The control block is the way a PLC is used to control the HMI. Through the settings set in the registers, the controller which is connected to HMI can know HMI internal operation, i.e. screen switch, backlight on and off, current priority, curve sampling data and clear flag, etc. information and the user can also get the current system status of HMI.
The register is a continuous data block and its length is from 0 to 8 words (Fig. 3-4-2). When using control block features, the actual length of control block is determined by the used control block features. For example, when Screen Switch feature (Screen Number Designation Register) is used, the control block must be set to a length of 1 or more. At this time, only Screen Number Designation Register can be used. One more example, when using History Buffer features (Sampling History Buffer Register), the control block must be set to a length of 4 or more. At this time, only Sampling History Buffer Register can be used.
In addition, when using the function of Multi-language Setting Value Bit (System Control Flag Register), it is best that the length of the control block be set to 8 words. At this time, all the register in control block can be used. When the control block is set to a length of zero, the control block is disabled. The function and explanation of each WORD is listed as Table 3-4-1 below. In the following table, in the following example 1 we assume that the user uses a Delta PLC, so the available starting addresses in control block are Dn ~ Dn+7 (D0 ~ D7).
In the following example 2, we assume that the user uses HMI internal register $, so the available starting address in control block is$n ~ $n+7 ($15 ~ $22). The user can choose if the control block designations are stored in PLC or HMI.
Table 3-4-1 Control Block Designations Revision May, 2010 3-25 Example 1 Example 2 Word Register Number (PLC register) (HMI register) Number Address Example Address Example 1 Screen Number Designation Register (SNIR) Dn D0 $n $15 2 Control Flag Register (CFR) Dn+1 D1 $n+1 $16 3 Curve Control Register (CUCR) Dn+2 D2 $n+2 $17 4 Sampling History Buffer Register (HBSR) Dn+3 D3 $n+3 $18 5 Clearing History Buffer Register (HBCR) Dn+4 D4 $n+4 $19 6 Recipe Control Register (RECR) Dn+5 D5 $n+5 $20 7 Recipe Number Designation Register (RBIR) Dn+6 D6 $n+6 $21 8 System Control Flag Register Dn+7 D7 $n+7 $22