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I have FMD88-10 PLC I wanted to perform Modbus read and write operation form this PLC for monitoring and control purpose. I have one Fronius solar Inverter and one Sinexcel Battery Inverter both are connected with PLC using Modbus TCP protocol. The ladder logic is written in this way that performing read and write operation in a continuous manner with respect time like in a never-ending loop. but PLC can able to perform read and write operation in these two devices one time means at the first time or the first cycle is able to read the value from Modbus register of that device but in next cycles, it was unable to fetch data from those devices.

I didn't find any reason behind this,  why it is behaving like this? I have attached my PLC code with this message. Please help me to find the error and its solutions. Thank You.

In your sample program "Initialization" you run SETBAUD to COMM1 but COMM2 was commented out. That means COMM2 (RS485) port will still be operating at default 38400,8,1,n
Sorry, I just mistakenly commented out COMM2 but I was really trying to communication with MRA4 Relay through COMM2. I know that COMM1 for RS232 and COMM2 for RS485 in my code I have  shown you wrong but actually I was trying to communicate through COMM2. Please don't mind.

But your "MBRTU" function contains READMB2 12,....    which means you are trying to use COMM2  (RS485) to talk to your device.
Yes, absolutely.
I am not sure why there was the line SETSYSTEM 12,1  in your initialization code. Are you trying to use Modbus TCP to talk to a device that is connected to COMM1 of the PLC using Modbus RTU? That is one purpose of SETSYSTEM 12,1, which is to act as a Modbus TCP to Modbus RTU gateway
No, I just want to talk with that device through COMM2(RS485) only. FMD88-10 acts as Modbus Client and MRA4 relay as a slave.

Also was there any data received into DM[4], DM[5].....DM[9]?
No, nothing.

You can remove the FOR NEXT Loop in the Checkstatus1 function because READMB2 function will run to completion and STATUS(2) will immediately indicate whether the communication was successful so there is no need to put a FOR NEXT loop to test for STATUS(2).
Okay, I will do it. From STATUS(2) function I am getting "0" return.

You can remove the checkcom function as it does not serve any purpose and only will slow down the program.
Okay, I just use this function to check if any data received in COMM port, if READMB2 command successfully applied. But both STATUS(2) and INCOMM(2) gives "0" and "-1" returns respectively.

Woodward MRA4 relay Modbus Data point

Link of cluster controller modbus-Tcp datamanger

https://drive.google.com/file/d/0B_qhEtFVTRB1X3pqaFZhcUxpMEU/view?usp=sharing

Did you get a successful connection before you run the WRITEMODBUS command?
 Yes
30001 to 39999  - can only be read using Modbus function 04 and the binary address = Modicon address - 30001
So to read anything in the 30001 to 3999 you use SETSYSTEM 4.4 to change to read the input register, then subtract the given address by 30001
E.g. Version number at address 30001
so  READMODBUS should read from binary address = 30001 - 30001 = 0
I am now able to read data from Input registers.

40001 to 49999 can only be read using Modbus Function 04 and the binary address =( Modicon address - 40001)

So if you want to write to Modicon address 40493 you should be writing to 40493-40001 = 492.
While I am trying this as per my code it gives "writing failure" by checking the STATUS(2) function.

Thanks for your reply

Is the FMD88-10 the master to read 32-bit data from a slave device?
Yes, FMD88-10 is Master device and I want to read/write data from a cluster Controller(Slave Device).

All Modbus registers are accessed in 16-bit only. To access 32-bit data you normally would need to read two adjacent Modbus registers into two DM16[] and access them as a DM32[] variable.
I have tried in this way before.

The PLC handles number in Big Endian. If the slave (server) arrange the data in Little Endian you will need to use TBASIC to swap the two adjacent DMs so that the are arranged in  Big Endian.
okay, Thank you.

I was trying to read from SMA Cluster Controller's INPUT Register(register number 30005, datatype U32) which contain Serial number of this device but PLC is unable to do that. I have attached my TBASIC code along with SMA cluster controller's Modbus data manager with this reply. please find the attachments and please help me to solve this problem

Hello Folks,
 I am using Trilogi PLC FDMD88-10 model and I am using it for Industrial purpose. I was trying to Connect with a Cluster Controller(MODBUR RTU and MODBUS TCP both are supported)  to Read Modbus Registers value from it through MODBUS/TCP.  I could not connect with CLUSTER CONTROLLER. I have given proper IP address of Cluster Controller, Proper Input Register address also I have checked the Connection Status from INPUT$() function it also returns nothing. I don't understand what is my fault. I have uploaded my PLC code my humble request is please check the code and help me to solve my problem.

Hello folks,
I am using Trilogi PLC FDMD88-10 model and I am using it for Industrial purpose. So I  would like to know how can I secure my code for confidential purpose such that no one can copy, view my code. what are the procedure to authenticate my Code?
Please suggest me. Thank you.