adccommunitymod (AutomationDirect) asked a question.
Created Date: May 11,2016
Created By: mastmach
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I'm planning on connecting a digital sensor (Keyence GT2 with a DL-RS1A RS-232C ASCII module) to a Click PLC's Port 3 via the FA-ISOCON RS232/RS485 converter. This is my first experience with RS485 ASCII, and I have some questions. I 've read the manuals for both the Click PLC and the FA-ISOCON. I understand that RS485 is a multinode network (although in my case, it will only have two nodes). The manuals talk about a Network master, and network slaves. Do I need to configure either the Click PLC or the FA-ISOCON to be the network master? If so, how do I do that? I don't see any way to configure the FA-ISOCON with a node number or a master/slave status, and the Click PLC's port 3 can only be given a node number in MODBUS mode. Is this simply a matter of programming? For example, if I program the Click to Send a command, then Receive a response, does that inherently make the Click the Network master? If so, how does that work if I did have multiple nodes on my network? For example, let's say that I had multiple RS232 sensors, each connected to an FA-ISOCON. Is there a way to configure the FA-ISOCON to send certain commands on to its sensor, and ignore other commands? Another question: I don't see any way to set the baud rate on the FA-ISOCON. Does this device simple rebroadcast messages back and forth between the RS485 and RS232 networks, matching the baud rate of the incoming message? Or does it need to be configured somehow?
Created Date: May 11,2016
Created by: mastmach
I'm planning on connecting a digital sensor (Keyence GT2 with a DL-RS1A RS-232C ASCII module) to a Click PLC's Port 3 via the FA-ISOCON RS232/RS485 converter. This is my first experience with RS485 ASCII, and I have some questions. I 've read the manuals for both the Click PLC and the FA-ISOCON.
I understand that RS485 is a multinode network (although in my case, it will only have two nodes). The manuals talk about a Network master, and network slaves.
Do I need to configure either the Click PLC or the FA-ISOCON to be the network master? If so, how do I do that? I don't see any way to configure the FA-ISOCON with a node number or a master/slave status, and the Click PLC's port 3 can only be given a node number in MODBUS mode.
Is this simply a matter of programming? For example, if I program the Click to Send a command, then Receive a response, does that inherently make the Click the Network master?
If so, how does that work if I did have multiple nodes on my network? For example, let's say that I had multiple RS232 sensors, each connected to an FA-ISOCON. Is there a way to configure the FA-ISOCON to send certain commands on to its sensor, and ignore other commands?
Another question: I don't see any way to set the baud rate on the FA-ISOCON. Does this device simple rebroadcast messages back and forth between the RS485 and RS232 networks, matching the baud rate of the incoming message? Or does it need to be configured somehow?
Created Date: May 11,2016
Created by: andremholmes
If you use port 2 of the Click you just configure the port to ASCII.
Created Date: May 11,2016
Created by: Do-more PE
Unless the ASCII device itself has a place for a node, it can't go on a multi-drop network and work properly.
The FA-ISOCON is a simple rebroadcasting device. It doesn't have any real "smarts ".
Created Date: May 11,2016
Created by: mastmach
@andremholms Thanks for the reply. I need to use Port 3 and RS485, because the distance between the two nodes is too large for RS232.
Created Date: May 11,2016
Created by: mastmach
Do-more PE Thanks. I think I understand. So when the FA-ISOCON manual talks about "Network Master " and "Network Slaves ", that isn't really anything built into the RS485 network architecture or the ASCII protocol; it is only something that needs to be built into whatever programming I set up. Does that sound right?
Created Date: May 11,2016
Created by: Do-more PE
If you send something over RS-485 all of the devices will "see " it. So unless the end device has a way to identify that the transmission is specifically for them, everyone will answer or do the command that was sent.
The typical way for devices that are built to be on a network is for the slave device to have a slave address that you call out when you send the message. Without an address it's like junk mail. It clutters everyone's mailbox (input buffer) and everyone may respond to the "letter ".
Created Date: May 12,2016
Created by: andremholmes
I got this from page 9 of the Keyence Manual
Command format
You can send specific commands based on ASCII codes from an external device to DL-RS1A.
For information on the parameters used in the command, refer to "Parameters of Commands and
Responses " (page 10).
Sample command format structure
(1)With the first two bytes, specify the communication command.
(2) Specify the ID number assigned to the target sensor amplifier using two digits (ASCII characters).
(3) Specify the data number for the data you want to read from or write to the sensor amplifier using
three digits (ASCII characters).
(4) Insert CR or CR + LF as the command delimiter.