Omron CS1W-ETN21 Communications Port Completion Codes, Timing of Communications Flag Changes

Communicating between OMRON PLCs Section 6-6

Communications Port Completion Codes

The status of a SEND(090), RECV(098), and CMND(490) instruction after execution is reflected as a communications port completion code, in one word (two bytes) of data as shown in the following table. (The value is 0000 during instruction execution.) The recorded status is saved until execution of the next instruction.

Word	Contents
A203	Communications Port 0 Completion Code
A204	Communications Port 1 Completion Code
A205	Communications Port 2 Completion Code
A206	Communications Port 3 Completion Code
A207	Communications Port 4 Completion Code
A208	Communications Port 5 Completion Code
A209	Communications Port 6 Completion Code
A210	Communications Port 7 Completion Code

The meanings of the communications port completion codes are the same as those for FINS commands and responses. When CMND(490) is used, how- ever, even if a FINS command has an abnormal completion, it will not be reflected in the communications port completion code. For details, refer to Communications Port Error Flag and Completion Codes for CMND(490) below.

Bits 08 to 15 in the communications port completion code correspond to the first byte of the response code, and bits 00 to 07 correspond to the second byte. For details, refer to 8-5 Troubleshooting with Response Codes.

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 reception 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 recorded in a communications port completion code.

Timing of Communications Flag Changes

•The Communications Port Enabled Flag remains OFF during communica- tions 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 trans- mission or reception.

•The Communications Port Error Flag turns OFF with the execution of the next communications instruction even if there was an abnormal comple- tion.

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