CI867 Hardware Configuration
I am trying to receive data from serial devices by connection from CI867 to Nport S8455I Moxa switch (Gateway) over an Ethernet Switch (RS20). Under the Moxa Switch, I have some serial devices (Modbus TCP slaves). You can find the network map and Hardware configuration in the attachment. I couldn't make the connection, I receive error as you see.
What is the role of Moxa Switch here, Modbus TCP Client or TCP Server?
Should I assign IP for Gateway in matching range of the Controller IP?
Does anybody know how to configure Moxa switch serial ports in this case?
Some my ideas:
- S8455 Moxa should be configured. As per my understanding, it receives a data from serial devices and transfer it to TCP/IP. It is described as managed switch so it should be configured by means of WEB interface or other software. At least you shoud assign IP address to it - in your eample 192.168.127.105?
- S8455 is described with a possibility for ring operation. I don't know if you are able to connect S8455 to M20 by fibre optic? Easiest way is to try to ping Moxa 192.168.127.105 from the side of M20. If ping is OK, then the line between S8455 and M20 works
-S8455 should be set as TCP Server (means slave). CI867 should be configured in the same network, as in your example 192.168.127.100
- I suppose serial ports should be configured again with the Moxa's software (WEB interface or serial?). Look in help of this software, I can't find it in internet
As per your configuration diagram, Moxa Nport S8455I shall work as gateway (Protocol converter) to between Modbus TCP/IP and Modbus RTU communication/protocols.
You have to configure Moxa Nport gateway using webserver. You can also change the default IP address (192.168.127.254) using webserver. Note: IP address of CI867 and Moxa gateway shall be in same class/series, ex.. 192.168.127.x or 192.168.1.x etc.
Once you have access to webserver of Moxa Nport, you can configure it as TCP server and also parameter/setting of serial ports (Baud rate, parity, data bits etc.. and importantly interface - RS232/RS485).
When the required configuration of Moxa gateway is done then, you will be able to communicate with serial (Modus RTU) slave connected to it.
In control builder application logic, Channel no. shall be position of CI867 (1, in your case as per attached CBM configuration) and partner shall be 1.1.x.
Let me know if you need any more details on configuration in control builder.
I already configured Moxa IP and also Serial Port Parameters by using Webserver. However, I am not sure if it is correct or not. If my hardware configuration is correct, then what am I missing? You can see Moxa settings in the attachment.
Thanks for your support.
In order for a MODBUS RTU device to be integrated into a TCP/IP network, it is necessary to use a MODBUS TCP/IP to MODBUS RTU gateway and not just a TCP/IP to Serial gateway device.
A true MODBUS TCP to RTU gateway reformats the MODBUS message from RTU to TCP/IP format and vice versa before sending the data over the respective side of the gateway.
The MOXA device you are using, AFAIK, only acts as a TCP/IP to serial gateway device, which simply encapsulates the serial data at the MOXA device's serial ports into TCP/IP packets and sends it over the Ethernet network.
If this is the case, the CI867, which expects a TCP/IP packet in the MODBUS TCP/IP response format, will actually receive response in MODBUS RTU format and would inturn generate an exception response such as CRC error etc.
To verify this, you could use MODBUS POLL software and configure its driver as TCP/IP and use this to communicate with your Serial devices over the the MOXA device.
MODBUS POLL software actually encapsulates a MODBUS RTU message in a TCP packet and sends it over ethernet.When this packet is received by the MOXA device, the device extracts the MODBUS RTU message from the TCP/IP packet and then sends it to the MODBUS RTU slave device. This way, both the SLAVE and the MASTER/CLIENT are communicating using the same language and understand each other.
To verify with MODBUS poll, AFAIK, the Operation mode in MOXA settings must be TCP Server.
PS: If possible, try to verify from its data sheet/ manual, whether this device supports MODBUS data translation.