Chapter 8 Exercising program
8-39
C) Read response frame (Temperature controller’s response : sends temperature value of 12 channels)
Classification
Header
Device ID
Command
Status
Channel
number
Data
Frame
[DLE][ACK]
01
02
00
0c
12 word data
BCC calculation range
BCC
Tail
[DLE][EOT]
Communication protocol in [Figure 8.20] is a protocol for HEX communication with data areas all in HEX except
header and tail.
Communication frame is described next.
Header : Indicates start of frame with [DLE][STX] in request frame and continuous control characters
of [DLE][ACK] in response frame.
Tail : Indicates end of frame with [DLE][ETX] in request frame and continuous control characters of
[DLE][EOT] in response frame.
Device ID : Means temperature controller No. with ‘01’ used in.
Command : Dependent on Read/Write commands, ‘01’ for Write and ‘02’ for Read command.
Address : Memory address of temperature controller.
Channel number : I/O channels number of temperature controller.
Data : I/O channel data of temperature controller.
Status : Indicates the status of response frame. ‘00’ if displayed means response successful.
BCC : HEX data sum from Device-ID next to header to BCC prior.
4) Frame edit
Define 3 frames above through Frame Editor to download to Cnet I/F module.
A) Write request frame : Write request frame as of TX frame is configured to send data to specified protocol
through segment of ARRAY type. Next is Frame Editor screen of TX frame edited. CON_WR is entered in
frame name, CONST in segment 1, HEX for channel number in Device-ID, ARRAY variable in segment 2 and
24 bytes for TX number of data.