9DEDICATED INSTRUCTIONS

Error

MELSEC-Q

(1)When a dedicated instruction is completed abnormally, the abnormal completion signal, (D)+1, turns on and the error code is stored in the transmission result (S1)+1.

In case of operation errors, the error flag (SM0) turns on and the error code is stored in the SD0.

See one of the following manuals according to the error code, and check and correct the error.

<Error code>

4FFFH or less : QCPU(Q Mode) User's Manual

(Hardware Design, Maintenance and Inspection) 7000H or more: Section 10.2 of the User's Manual (Basic)

Program example

A program that sends data stored in D10 to D11 using an on-demand transmission

When input/output signals of the Q series C24 are from X/Y00 to X/Y1F

On-demand transmission command pulse

Set the transmission channel to CH1.

Set the send data count to 2 words.

Set the transmission data to D10 to D11.

Reset the normal completion flag.

Reset the abnormal completion flag.

Set the transmission ready flag.

On-demand transmission execution

Normal completion

Abnormal completion

Reset the transmission ready flag.

POINT

(1)The status of communication via dedicated instructions can be read by an SPBUSY instruction.

(2)Designate the storage capacity of transmission data (stored in D10 to D11 in the program example above) and data length (stored in D2 in the program example above) within the range of the buffer memory the user has assigned for an on-demand function.

9 - 4

9 - 4