Chapter 6 Task code communication
6.1.2 Frame
format
The task code format of EH-ETH2 is shown in Figure 6.2. If you make an application program for host
computer, you should follow this format, which is different from the standard RS-232C protocol. The data
must be binary.
Cautions
EH-ETH2 can accept only
binary data.
ASCII data is not available.
Item Name Size(byte)
(a) Termination
command
1
(b) Through
no.
1
(c) LUMP
address
4
(d)
Request/Response task code
Max. 244
(a) (b)
(c)
(d)
Figure 6.2
Frame format
(a) Termination command
To use control CPU module.
H00: Normal operation. CPU will reply according to the requested task code.
HFF: If CPU receives the task code with HFF, the CPU will stop processing the last task code sent from a host
computer. If there is no processing to be stopped, this command is ignored.
H01 to HFE: EH-ETH2 discards the task code with command H01 to HFE.
(b) Through no.
Through number to add request task code
Any number available. CPU will reply with adding same through number as in the command from host
computer. You can use it for debugging or your own purpose so that host computer can handle several
messages easily at the same time.
(c) LUMP address
H/EH series network address
See Section 6.1.3 for detailed information.
(d) Request/Response task code H/EH series communication command code
See "Appendix B Task Code Specifications".
Caution
- If EH-ETH2 receives the 2nd task code (2) before the 1st task code has not executed, EH-ETH2 will reply "
busy
response"
against the 2nd task code (2)’.
Host
Computer
EH-ETH2
CPU module
(1)’
(2)
(1)’
(1)
(2)’
(1)
(1)
6-2
