PDF《CNC》

1 2. Usage of DDB Function with Ladder

2 2.1 Basics of commands

2 2.2 Basic format of control data

2 2.2.1 Control signals (Rn or Dn)3 2.2.2 Section No. (Rn+1 or Dn+1)3 2.2.3 Sub-section No. (Rn+2, Rn+3 or Dn+2, Dn+3)3 2.2.4 Data size (Rn+4 or Dn+4)3 2.2.5 Read/write designated axis (Rn+5 or Dn+5)4 2.2.6 Read/write data (Rn+6, Rn+7 or Dn+6, Dn+7)4 3. Section No. List

5 4. Sub-section No. List

6 5. Explanation of Read/Write Data

19 5.1 How to refer to the data

19 5.2 Data unit system

20 5.3 Explanation of data details

21 6. Example of DDB with Ladder Circuit

66 1. Outline -

1 - 1. Outline This manual describes the DDB (Direct Data Bus) function used to realize data input/output with a CNC while running a program developed with the user PLC ladder language. DDB includes the synchronous type (DDBS) and the asynchronous type (DDBA), but only the asynchronous type will be explained in this manual. DDB is a function that allows the PLC to directly read and write the various data in the CNC. By setting the information required for reading and writing into the buffer and calling out the DDB function, the PLC can set (write) the designated data into the CNC. Generally, the data is read and written in one piece units, but data related to the control axis can be processed for the designated number of axes. Features of this function include that the read data can be referred to in the step immediately following the execution of the DDBA command. This also applies to the written data. (Note that for the parameters, they may not be valid immediately after writing.) This manual is organized in the following manner after the first chapter. Please refer to the required section for use. 6. Example of DDB with Ladder Circuit 5. Explanation of Read/write Data 4. Sub-section No. List 3. Selection No. List 2. Usage of DDB Function with ladder 2. Usage of DDB Function with Ladder -

2 - 2. Usage of DDB Function with Ladder 2.1 Basics of commands S.DDBA Rn/Dn Set control data with MOV command, etc. (Note 1) ACT (Note 1) The file registers (Rn) and data registers (Dn) in the range usable by the user can be used in the control data buffer of the asynchronous type DDB . The file registers (R) usable by the user are from R4000 to R4499 (not backup) and from R6400 to R7199 (backup). 2.2 Basic format of control data Rn (Dn) Control signal Rn+1 (Dn+1) Section No. Rn+2 (Dn+2) Sub-section No. Rn+4 (Dn+4) Data size Rn+5 (Dn+5) Axis/part system designation for read/write Rn+6 (Dn+6) Read/write data (for 1st axis) Rn+8 (Dn+8) (for 2nd axis) Rn+10 (Dn+10) (for 3rd axis) Rn+12 (Dn+12) (for 4th axis) : : : Rn+32 (Dn+32) (for 14th axis) (Note 1) The part system designation is used when there is a multi-part system specification. (Note 2) Always secure

4 bytes as the buffer for one read/write data item. (Note 3) Always secure the buffer size equivalent to

14 axes (28 words data). (Note 4) For example, if only the 3rd axis is designated, the data for the 3rd axis will be the read/write data. 2. Usage of DDB Function with Ladder -

3 - 2.2.1 Control signals (Rn or Dn) Warning output * F E D C B A

9 8

7 6

5 4

3 2

1 0 Error during chopping (not used) No option Size over Number of axes illegal Section/sub-section No. error Write protect Error occurrence

0 : Read designation

1 : Write designation Set by PLC during DDB command execution Set by controller at completion of DDB command Last four digits of the data during reading/writing of variables correspond to the decimal place *Warning output bit 4=

1 : Variable data blank