Galil Motion Control RIO-47**0, Руководство пользователя

Страница: 19 / 107

connect to the slave. (Ex: IHB=151,25,255,9<179>2. This will open handle #2 and connect to the IP
address 151.25.255.9, port 179, using TCP/IP)
Once the IH command is used to connect to slaves, the user can communicate to these slaves by sending
commands to the master. The SA command is used for this purpose, and it has the following syntax.
SAh= "command string"
Here "command string" will be sent to handle h. For example, SAA=”XQ” command will send an XQ
command to the slave/server on handle A. A more flexible form of the command is
SAh= field1,field2,field3,field4 ... field8
where each field can be a string in quotes or a variable.
When the Master/client sends an SA command to a Slave/server, it is possible for the master to determine the
status of the command. The response _IHh4 will return the number 1 to 4. 1 indicates waiting for the
acknowledgement from the slave. 2 indicates a colon (command accepted) has been received. 3 indicates a
question mark (command rejected) has been received. 4 indicates the command timed out.
If a command generates multiple responses (such as the TE command), the values will be stored in _SAh0
thru _SAhn where n is the last field. If a field is unused, its _SA value will be -2^31.
See the Command Reference for more information on the SA command.
Which devices receive what information from the RIO depends on various things. If a device queries the
RIO, it will receive the response unless it explicitly tells the RIO to send it to another device. If the
command that generates a response is part of a downloaded program, the response will route to whichever
port is specified by the CF command (either a specific Ethernet handle or the RS232 port). If the user wants
to send the message to a port other than what is specified by the CF command, add an {Eh} or {P1} to the
end of the command (Ex. MG{EB}"Hello" will send the message "Hello" to handle #2 and MG{P1}”Hello”
will send it to the serial port).
Handling Communication Errors
A reserved automatic subroutine which is identified by the label #TCPERR can be used to catch
communication errors. If an RIO has an application program running and the TCP communication is lost, the
#TCPERR routine will automatically execute. The #TCPERR routine should be ended with the RE
command.
Multicasting
A multicast may only be used in UDP/IP and is similar to a broadcast (where everyone on the network gets
the information) but specific to a group. In other words, all devices within a specified group will receive the
information that is sent in a multicast. There can be many multicast groups on a network and are
differentiated by their multicast IP address. To communicate with all the devices in a specific multicast
group, the information can be sent to the multicast IP address rather than to each individual device IP
address. All Galil devices belong to a default multicast address of 239.255.19.56. This multicast IP address
can be changed by using the IA>u command.
Unsolicited Message Handling
Unsolicited messages are any messages that are sent from the controller that are not directly requested by the
host PC. An example of this is a MG or TP command inside of a program running on the controller. Error
messages are also “unsolicited” because they can come out at any time. There are two software commands
that will configure how the controller handles these unsolicited messages: CW and CF.
The RIO has 3 Ethernet handles as well as 1 serial port where unsolicited messages may be sent. The CF
command is used to configure the controller to send these messages to specific ports. In addition, the Galil
RIO-47xxx Chapter 3 Communication ● 13