ElmoMC Multi-Axis Motion Controller-Maestro - Manual (Page 248)

Chapter 14: Maestro Message Queue
In the user host program, messages can be retrieved from the M aestro Motion Controller
via two different methods. One mechanism is defined in the Maestro API, for a system
that includes a single Maestro Motion Controller.
For a networked system that includes several Maestro devices, the Maestro Message
Queue interface makes it possible to retrieve and analyze the messages sent by each
device. The Maestro Message Queue mechanism is supported by the TnElmoS .exe COM
server via the IMessageQueue Interface.
14.1
User Message Methods
The IMessageQueue includes the following methods (Table 14-1).
Table 14-1 IMessageQueue methods
Method Description Call Format and Parameters
Subscribe: Subscribe to User Messages
from the Maestro device. After
subscribing, all the messages that arrived
are copied to the Message Queue
instance Subscribe ([in]DWORD dwIP)
dwIP - the Maestro device IP address
Unsubscribe: Unsubscribe from the
Maestro device Unsubscribe ([in]DWORD dwIP)
dwIP - the Maestro device IP address
MessageQueueSize: Get the number of
User Messages in the Message Queue MessageQueueSize ([out]DWORD *pSize)
pSize - a pointer for the DWORD variable to
return the number of Messages.
MessageQueueErase: Clear the Message
Queue MessageQueueErase ()
ReadMessage: The host application uses
this method to read a message from the
Message Queue ReadMessage
([out]DWORD
*pIP,[out]DWORD *pID,[out]DWORD
*pWParam,[out]DWORD
*pLParam,[out]DWORD *pTime)
pIP - a pointer for the DWORD variable for the
IP address of the Maestro device
pID - a pointer to the DWORD variable to get
the Message ID
pWParam , pLParam – pointers to DWORD
variables to get the Message Data
pTime – pointer to DWORD variable for the
Message Time Stamp
Maestro Software Manual
MAN-MASSW (Ver. Q)
14-1