Bit Block Read
- CIMON (Unlicensed)
This function is to assign PLC device memory directly to read bit block. The data can be assigned up to 16 pieces repeatedly.
But, The total sum of the word data is not to be over 1024 bits.
Requested Format (PC -> PLC)
Bit Block Read(Master sends.)
Cmd – 72h
ID | Frame No. | Cmd | Res. | Length | Data | Check Sum |
ID : This is a 9-byte string like "KDT_PLC_M".
FrameNo : This, 1-byte data with the range from 0 to 127, is the number of the frame controlled by Master party.
Cmd : 1 Byte, 72h(Word Block Read)
Res : 1 byte of a reserved device (00h)
Length : Total number of the bytes of a frame data device
Data : (Ex.) The case to read 128 bits from ‘T0000’
Offset (Byte) | Meaning of Data | Ex. | Remarks |
0 | Main Device Prefix (ASCII) | ‘T’ | Assigns the ASCII Prefix of the bit device supported from a PLC. |
1 | Sub-Device Prefix or ‘0’ (ASCII) | ‘0’ | Sub-Prefix in case of the 2-character prefix device (TC, TS, CC, CS) |
2 | Device Address (ASCII) | ‘0’ | The bit address of a corresponding device is used. |
3 | ‘0’ | ||
4 | ‘0’ | ||
5 | ‘0’ | ||
6 | ‘0’ | ||
7 | ‘0’ | ||
8 | Read Size (Bit) | 00h | Value in the range from 0001h to 0400h (1~1024) |
9 | 80h |
Check Sum : This is 2-byte value. After the entire frame is binary-summed by the byte, the lower 2-byte in the result value is used.
Responded Format
ACK Response
This is the frame sending the data of the bit block that Master requests to read, in case of receiving Master’s request correctly and responding.
Cmd – 72h
Data Device
Offset (Byte) | Meaning of Data | Ex. | Remarks |
0 ~ 9 | Block Address | - | The first 10 bites in the data of the block assigned to a Master frame are copied and stored. |
10 | Bit Data #0 | ‘1’ | The first bit data of Read Block |
11 | Bit Data #1 | ‘1’ | The second bit data of Read Block |
....... | |||
m | Bit Data #n |
| The last bit data of Read Block |
NACK Response
In case that the service to ‘Word Block Read’ cannot be given due to error in a system or other reason,
Cmd – 41h
In the case of responding to Error Code (Refer to the Error Code table for the Exclusive Service.)
Data Device
Offset (Byte) | Meaning of Data | Ex. | Remarks |
0 | Error Code | 00h | Error Code (Error in the size of the requested data) |
1 | 04h |