Omron CS1W-ETN01 Operation Manuals page 85

Sending Commands From a PC
Timing of Communications Flag Changes
Example
Communications Port Enabled Flag
Communications instruction:
SEND(090), RECV(098), CMND(490)
Communications Port Error Flag
Communications Port Completion Code
Communications Port Error Flag and Completion Codes CMND(490)
Errors that occur when CMND(490) is used generate a Communications Port
Error Flag and are recorded in a communications port completion code only in
the following cases:
• When a response timeout error has occurred.
• When the number of communications data bytes exceeds the maximum value
for the Unit (i.e., 2,000 bytes for the Ethernet Unit).
• When the actual number of response bytes is greater than the number of re-
ception bytes that has been set. (The response is not stored in this case.)
Errors other than these are recorded in the response codes of the responses
stored from the beginning response storage word onwards. Be careful of these,
because there are no Communications Port Error Flags and they are not re-
corded in a communications port completion code.
• The Communications Port Enabled Flag remains OFF during communications
and turns ON when they are completed (regardless of whether or not an error
occurs).
• The Communications Port Error Flag retains its status until the next transmis-
sion or reception.
• The Communications Port Error Flag turns OFF with the execution of the next
communications instruction even if there was an abnormal completion.
Instruction 1
being executed.
Completion 0000 (Normal completion)
Instruction 2
Instruction 3
being executed.
being executed.
0000 (Normal completion)
(Unit address setting error)
Section 5-3
73