Communications Control Procedure - Omron E5ZE-8 Communications Manual

Communications Control Procedure

1-1

Communications Control Procedure

68
The communications procedure of the E5ZE is a special conversation type.
In each E5ZE system, all communications are initiated by the host computer
of the system by sending a character string called command block to an E5ZE
of the system. The E5ZE then sends a character string called response block
back to the host computer, i.e., each time a block is transmitted, the transmis-
sion right is also transferred. Each block begins with a start character, @, and
the unit number of the E5ZE and ends with an FCS and a terminator.
The E5ZE sends a response block back to the host computer whenever the
host computer sends a command block to the E5ZE. The response block is
processed by the host computer.
@
Unit no.
Header code
Host
Text
system
FCS
Terminator
Command block
E5ZE
Note Command Block:
Response Block:
The host computer must be set up to read the responses sent by the E5ZE. If
the host computer does not read any response, the reception buffer of the
host computer may overflow.
• Communications after E5ZE Turned OFF and ON
The host computer can send a command block to the E5ZE at least 4 s af-
ter the E5ZE is turned ON.
When the E5ZE is turned OFF and ON, do not fail to initialize the reception
buffer of the host computer before sending a command from the host com-
puter.
• The E5ZE requires a maximum of 4 s to process a command block, which
must be taken into consideration when writing programs for the E5ZE.
• An interval of 20 ms minimum is required for the host computer to send a
command block after receiving a response block. If an interval less than 20
ms is set on the host computer, communications may not be possible.
@
Unit no.
4 s max.
Header code
Text
FCS
Terminator
Response block
A block sent from the host system. (Character string)
A block sent from the E5ZE. (Character string)
Section 1-1
@
Unit no.
Header code
Text
FCS
Terminator
Command block
20 ms min.