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NL240/CR800 Communication via Modbus protocol


fpborges Nov 19, 2013 01:28 PM

Dear colleagues,

We need to receive data from CR800 via ModBus TCP Gateway, using a NL240 Network Device. First of all, we've configured the device's RS-232 Port with the MODBUS/TCP gateway option. Then, we've sent the ModbusSlave() program example to the datalogger using the 502 address code as the port number, as recommended by the CRBasic Help and the manuals. Lastly, we've tried to stablish connection via Setup Wizard, linking the RS-232 ports from the datalogger and the NL240 through a NULL Cable, but we've failed to accomplish that.

Could you help us through this situation? What's the better configuration to connect datalogger CR800 using Modbus protocol, TCP/IP or Master/Slave?

We've read the CR800 Series' manual, but this document recommends to contact Campbell Scientific for more information on the "Modbus over TCP/IP" communication.

Regards,

Francisco.


Sam Nov 22, 2013 11:48 AM

You have a few options. The first, in my opinion, is the preferred one.

1)Make sure the CR800 OS is up to date. Set the NL240 so that Bridge Mode = enabled. Connect the NL240 to the CR800's CS I/O port.

Use the ModbusSlave instruction as you probably already have. Something like:

ModBusSlave (502,115200,SlaveAddr,MBRegVar,MBCoilVar,0)


2) Set the CS I/O configuration to Modbus TCP Gateway and connect the NL240 CS I/O port to the datalogger's CS I/O port using a SC12 or normal / straight through serial cable.

Assuming that the SDC Address setting in the NL240 is set to 7, make your ModbusSlave instruction something like:

ModBusSlave (ComSDC7,115200,SlaveAddr,MBRegVar,MBCoilVar,0)


3) Set the RS-232 configuration to Modbus TCP Gateway and connect the NL240 RS-232 port to the datalogger's RS-232 port using a normal / straight through serial cable.

Assuming that baud rate setting for RS-232 in the NL240 is set to 115200, make your ModbusSlave instruction something like:

ModBusSlave (ComRS232,115200,SlaveAddr,MBRegVar,MBCoilVar,0)


FheRivas Jul 20, 2018 01:29 PM

Hi. I have a problem.

I need to use my CR800 how Modbus Master and NL241 to communicate with another device via WIFI.

The other device is a Modbus Slave (IOZone 560 device). This device uses the RS485 protocol.

By means the USR-WIFI232 device I convert the RS485 to WIFI. I used the IOServer Emulator to test the communication and its OK.

The CR800 configuration is the next: OS Version>CR800.std.32.02; PPP>Inactive; and the rest of the data are factory defaults.

The USR-WIFI232 create the network and assign the IP=10.10.100.100 to NL241 device. So the NL241 Configuration is the next: Bridge Mode>Disable; OS Version>NL241.09.01; RS232>Pakbus, 9600; CSI/O>Pakbus, SDC Address 7; Pakbus>678, Pakbus/TCP Service Port>6785. The rest of the data are factory defaults.

With my IOServer emulator Modbus, I have the communication with the IOZone 560 vía WIFI. The access configuration is Remote IP Address>10.10.100.254 (Gateway), Remote port>8899 (Gateway), Socket>TCP, Local Port>49884, Interface>10.10.100.101 (assigned to my computer).

My firts CRBasic was:
BeginProg
Scan (1,sec,1,0)
ModbusMaster(ModbusResult,ComSDC7,9600,1,4,Modbus(),1,5,1,1)
NextScan
To communicate CR800-MD485-IOZone560 and was successful

And now my new CRBasic via WIFI:
BeginProg
Scan (1,sec,1,0)
TCPOpen("10.10.100.254",8899,30,500,Handle,3)
ModbusMaster(ModbusResult,Handle,9600,1,4,Modbus(),1,5,1,1)

This is my problem, I don't have the communication
CR800 plus NL241-WIFI-USRWIFI plus IOZone

Regards

Fernando Rivas, Mexico. ferivas21@hotmail.com


Liaisonmotta Nov 19, 2018 04:37 AM

Hi!

I have CR800 which was working fine via modem but now i installed NL200 connected to CR800 in bridge mode.

The problem is when i connect lan from NL200 dirrect the computer its working fine without loosing any connection but if i connect it to our swich i lost connection. (There is nothing wrong with swich cause i test it with more than one switch)

Regards,

Liaison

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