ProSoft Technology MVI69-ADM - Manual (Page 316)

Side-Connect API Library Functions MVI-ADM ♦ 'C' Programmable
Developer's Guide 'C' Programmable Application Development Module
Page 316 of 342 ProSoft Technology, Inc.
February 20, 2013
MVIsc_PLCMsgWrite
Syntax
int MVIsc_PLCMsgWrite(HANDLE handle, void *buf, WORD datatype, WORD size, BYTE
msgnum, WORD timeout);
Parameters
handle Handle returned by previous call to MVIsc_Open
buf Pointer to user buffer to receive data written by PLC-5
datatype Type of data (MVISC_DTYP_WORD or MVISC_DTYP_FLOAT)
size Number of items of type datatype to be transferred. The total size
cannot exceed 240 bytes.
msgnum PLC-5 message number (0 to 31)
timeout Maximum number of milliseconds to wait for message-write
Description
MVIsc_PLCMsgRead handles a PLC-5 message-write instruction. This function
should be called before the PLC-5 issues the message-write instruction.
handle must be a valid handle returned from MVIsc_Open. timeout indicates the
number of milliseconds to wait for the message-write instruction from the PLC-5.
A value of zero will cause the function to register the message handler and return
immediately, without waiting for the message-write instruction. In this case, the
MVIsc_PLCMsgWait function must be used to determine if the instruction has
been completed.
Return Value
MVISC_SUCCESS The command completed without error (Note: If timeout was set
to zero, this does not mean that the message-write instruction
has completed, but only that the message handler was
successfully registered. See MVIsc_PLCMsgWait).
MVISC_ERR_NOACCESS handle does not have access
MVISC_ERR_PLCTIMEOUT The timeout expired before the message-write instruction
occurred.
Example
HANDLE Handle;
int N;
/* Setup message-write handler for msg 2, wait 5 seconds */
rc = MVIsc_PLCMsgWrite(Handle, &N, MVISC_DTYP_WORD, 1, 2, 5000);
if (rc != MVISC_SUCCESS)
printf("ERROR: MVIsc_PLCMsgWrite failed");