Mitsubishi Electric MELSEC iQ-R Series User Manual page 289

■Send procedure
1.
Set all the input arguments for the module function block to be used.
2.
For message communications or tag communications (write) for which request data must be set, set required data to the
request data storage device or write data storage device.
• When the communication type is UCMM: Set data of the size specified by the input argument.
• When the communication type is Class3: Set data as big as the size of data set as Class3 communications parameters.
3.
Turn on i_bEN (execution command) of the module function block.
If an error occurs because an incorrect module function block is used or the module function block is set
incorrectly, o_bErr (Error completion) of the module function block turns on and an error code is stored in
o_uErrId (Error code). ( Page 404 Error Codes When a Module Error Occurs)
■Receive procedure
1.
When o_bENO (Execution status) of the module function block turns on, the result is stored in the output argument and
public variable.
2.
When o_bOK (Normal completion) of the module function block turns on, data of the size equal to the data size is stored
in the response data storage device for message communications and in the read data storage device for tag
communications.
If reception fails or an error response is sent from the external device at the time of reception, o_bErr (Error
completion) of the module function block turns on and an error code is stored in o_uErrId (Error code). (
Page 404 Error Codes When a Module Error Occurs)
■Operation
The following table shows the operations from i_bEN (Execution command) of the module function block turning on to turning
off according to the setting details of i_uTrigger (Trigger specification).
Trigger Type
Application Trigger
Cyclic
The following describes the operations when the trigger specification is changed during the time between
i_bEN (Execution command) of the module function block turning on and turning off.
• When the trigger specification is changed from Application Trigger to Cyclic, periodic transmission is not
performed. To enable periodic transmission, turn off i_bEN (Execution command) of the module function
block once, check that o_bENO (Execution status) is turned off, and turn on i_bEN (Execution command)
again.
• When the trigger specification is changed from Cyclic to Application Trigger, periodical transmission is
performed the RPI time after transmission immediately before the change of the trigger specification, and
then periodic transmission stops. To execute periodic transmission again, refer to the case where the trigger
specification is changed from Application Trigger to Cyclic.
Operation
Every time the module function block is executed, the received data is stored in the output argument and public
variable.
For Application Trigger, a request is executed only once. Therefore, when the module function block is executed after
o_bOK (Normal completion) turns on, the same data is stored continuously.
A request is sent periodically at the set RPI interval.
Every time pbo_udRequestCompleteCount (Execution completion count) of the module function block is updated, the
result to be stored in the output argument and public variable is updated.
12 FUNCTIONS
12.3 Message Communication Function (Client)
12
287