Modbus TCP Server for NJ & NX Controller. Modbus TCP server for Built-in Ethernet Port of NJ & NX Controller

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1 Function Block Reference MTCP_NJNX_Server Revision 2.0 Author JP Viskovic Date 20/12/ Support OMRON ELECTRONICS S.A.S. 14 Rue de Lisbonne Rosny-sous-Bois cedex Function Server Modbus TCP server for Built-in Ethernet Port of NJ & NX Controller File MTCP_NJNX.zip Conditions of use The FB Modbus TCP Server provides some read/write features in accordance with the specifications defined by the Modbus organization. The Modbus TCP Server function block is offered 'as is' and may serve as a basis for development. Users should previously test its adequacy to the final application. Omron could not be held responsible in case of malfunction. Principe The function block MTCP_NJNX_Server switch to LISTEN mode waiting for a Modbus TCP Client connection when Start input is activated. We recommend to use the FB in a periodical task to not overload the primary task. List of functions supported by MTCP_NJNX_Server: Code 0x01 0x02 0x03 0x04 0x05 0x06 0x10 0x17 Modbus Function Read Coils Read Discret Inputs Read Holding Registers Read Input Registers Write Single Coil Write Single Register Write Multiple Registers Read Write Multiple Registers

2 1- I/O variable of MTCP_NJNX_Server Input variable Name type range Description Start Bool OFF, ON Server Activation Input/output Variables Name type range Description Registers Array of 1025 Words 0-FFFF Register area ARRAY[ ] OF WORD Coils Array of 1025 bool OFF, ON Coil area ARRAY[ ] OF BOOL Output Variables Name type Range Description Connected Bool OFF, ON ON : a client is connected Error Bool OFF, ON Error flag ErrorID UINT 0 - FFFF Error Code returned by the socket or Modbus TCP server (see error code list below). TCP_Status _econnection_state Enum _CLOSED _LISTEN _SYN SENT _SYN RECEIVED _ESTABLISHED _CLOSE_WAIT _FIN WAIT1 _CLOSING _LAST ACK _FIN WAIT2 _TIME WAIT IP_Client String[24] w.x.y.z IP address of connected client Port_Client UINT Port number of connected client Error Code returned in ErrorID Code Description 0001 ILLEGAL FUNCTION Modbus 0002 ILLEGAL DATA ADDRESS Exception 0003 ILLEGAL DATA VALUE 2000 Local IP Address Setting Error 2001 TCP/UDP Port Already in Use 2002 Address Resolution Failed 2003 Socket Status Error 2004 error Local IP Address Not Set 2006 Socket Timeout 2007 Socket Handle Out of Range 2008 Socket Communications Resource Overflow JPV 20/12/2017 Page 2/5

3 Precautions in Using Socket Services Precautions for UDP and TCP Socket Services Communications processing are sometimes delayed when multiple functions of the built-in Ether- Net/IP port are used simultaneously or due to the contents of the user program. Communications efficiency is sometimes reduced by high communications traffic on the network line. The close processing for a close request instruction discards all of the buffered send and receive data for the socket. For example, send data from a send request instruction immediately before the close processing is sometimes not sent. After a socket is open, the built-in EtherNet/IP port provides a receive buffer of 9,000 bytes per TCP socket and 9,000 bytes per UDP socket to enable data to be received at any time. If the receive buffer is full, data received by that socket is discarded. Make sure that the user application always executes receive requests to prevent the internal buffer from becoming full. Precautions for UDP Socket Services The destination IP address can be set to a broadcast address for a UDP socket to broadcast data to all nodes on the network. However, in this case, the maximum length of send data is 1,472 bytes. lengths broken into multiple fragments (1,473 bytes or more in UDP) cannot be sent. For UDP socket, controls to confirm the reliability of communications, such as the confirmation of send data, are not performed. To improve the reliability of communications when you use UDP sockets, make sure the user program confirms that data is sent and resends data when necessary. Precautions for TCP Socket Services If the TCP socket is closed on the remote node without warning during communications (i.e., if the connection is closed), the socket at the local node must also be closed. You can use the Read TCP Socket Status instruction (SktGetTCPstatus) to see if the connection is closed. Immediately close the socket at the local node if the TCP socket at the remote node is closed. If the remote node s TCP socket closes without warning, the data to send may remain in the buffer at the local node. The remaining data is discarded in the local node s TCP close processing. The steps that are required in applications to avoid this include sending data from the sending node that permits closing and closing the socket only after checking the remote node. While open processing is performed for a TCP socket, a port that was closed first cannot be opened again for 60 seconds from the time the close processing is performed for the remote socket. However, this is not true if you specified 0 (automatic assignment by the Unit) as the port for the SktTCPConnect instruction. You can use Connect from another socket to open a connection to a socket that was opened with Accept. A connection is not opened if you try to use Connect from another socket to open a connection to a socket that was opened with Connect. Also, a connection is not opened if you attempt to use Accept from another socket to open a socket that was opened with Accept. Furthermore, you cannot use Connect from more than one other node to establish multiple connections with a single TCP socket that was opened with Accept on the built-in EtherNet/IP port. You can use the keep-alive function for TCP sockets at the built-in EtherNet/IP port. The keep alive function checks whether a connection is normally established when no data is sent or received for a certain period on the communications line where the connection was established. The built-in Ether- Net/IP port responds to checks from other nodes even if keep alive is not specified. JPV 20/12/2017 Page 3/5

4 Modbus protocol I/O memory area (CIO) Read Multiple Coils Fn01 Example: read 19 bits (CIO to ) Function Code 0x01 Function Code 0x01 Starting Address(H) 0x00 Byte Count 0x03 Starting Address(L) 0x14 Coil Status xCD Quantity of Coils(H) 0x00 Coil Status x6B Quantity of Coils(L) 0x13 Coil Status x05 0CH 1CH CH CH Italic characters show the ON/OFF(1/0) status of its bit condition. Reads registers in I/O memory area Fn03 Example: read 3 words (DM 1000 to DM 1002) Function Code 0x03 Function Code 0x03 Starting Address(H) 0x03 Byte Count 0x06 Starting Address(L) 0xE8 Register Value(H)DM1000 0xAB Quantity of Registers(H) 0x00 Register Value(L) DM1000 0x12 Quantity of Registers(L) 0x03 Register Value(H)DM1001 0x56 Register Value(L) DM1001 0x78 Register Value(H)DM1002 0x97 Register Value(L) DM1002 0x13 DM 1000 A B Writes single coil Fn05 Example: write 1 coil. ( ON) Function Code 0x05 Function Code 0x05 Output Address(H) 0x00 Output Address(H) 0x00 Output Address(L) 0x22 Output Address(L) 0x22 Output Value(H) 0xFF Output Value(H) 0xFF Output Value(L) 0x00 Output Value(L) 0x00 0CH 1CH CH CH Italic characters show the ON/OFF(1/0) status of its bit condition. JPV 20/12/2017 Page 4/5

5 Writes single register Fn06 Example: write &h3ac5 to register Function Code 0x06 Function Code 0x06 Register Address(H) 0x07 Register Address(H) 0x07 Register Address(L) 0xD0 Register Address(L) 0xD0 Register Value(H) 0x3A Register Value(H) 0x3A Register Value(L) 0xC5 Register Value(L) 0xC A C 5 Writes registers Fn10 Example: write 2 words into registers Function Code 0x10 Function Code 0x10 Starting Address(H) 0x03 Starting Address(H) 0x03 Starting Address(L) 0xE8 Starting Address(L) 0xE8 Quantity of Registers(H) 0x00 Quantity of Registers(H) 0x00 Quantity of Registers(L) 0x02 Quantity of Registers(L) 0x02 Byte Count 0x04 Registers Value(H) 0x3A Registers Value(L) 0xC5 Registers Value(H) 0x97 Registers Value(L) 0x A C Read and Write multiple registers Fn17 Example: read registers 1 & 2 ( ) and write CAFE into register Requête Réponse Donnée Donnée Function Code 0x17 Fonction Code 0x17 Starting Address(H) to read 0x00 Nbre of byte 0x04 Starting Address(L) to read 0x01 Valeur du register 1 (poids faible) 0x10 Quantity of Registers(H) to read 0x00 Valeur du registre 1 (poids fort) 0x01 Quantity of Registers(L) to read 0x02 Valeur du register 2 (poids faible) 0x20 Starting Address(H) to write 0x00 Valeur du registre 2 (poids fort) 0x02 Starting Address(L) to write 0x03 Nbre of registers (H) to write 0x00 Nbre of registers (L) to write 0x01 Nbre of byted octets à écrire 0x02 1ère valeur (poids fort) 0xCA 1ère valeur (poids faible) 0xFE A C C A F E JPV 20/12/2017 Page 5/5