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    node-red-contrib-s7

    3.0.0 • Public • Published

    node-red-contrib-s7

    A Node-RED node to interact with Siemens S7 PLCs.

    This node was created as part of the ST-One project.

    Install

    You can install this node directly from the "Manage Palette" menu in the Node-RED interface.

    Alternatively, run the following command in your Node-RED user directory - typically ~/.node-red on Linux or %HOMEPATH%\.nodered on Windows

        npm install node-red-contrib-s7
    

    NodeJS version 10 or greater and Node-RED version 1.0 or greater is required.

    Usage

    Each connection to a PLC is represented by the S7 Endpoint configuration node. You can configure the PLC's Address, the variables available and their addresses, and the cycle time for reading the variables.

    The S7 In node makes the variable's values available in a flow in three different modes:

    • Single variable: A single variable can be selected from the configured variables, and a message is sent every cycle, or only when it changes if diff is checked. msg.payload contains the variable's value and msg.topic has the variable's name.
    • All variables, one per message: Like the Single variable mode, but for all variables configured. If diff is checked, a message is sent everytime any variable changes. If diff is unchecked, one message is sent for every variable, in every cycle. Care must be taken about the number of messages per second in this mode.
    • All variables: In this mode, msg.payload contains an object with all configured variables and their values. If diff is checked, a message is sent if at least one of the variables changes its value.

    Variable addressing

    The variables and their addresses configured on the S7 Endpoint follow a slightly different scheme than used on Step 7 or TIA Portal. Here are some examples that may guide you on addressing your variables:

    Address Step7 equivalent JS Data type Description
    DB5,X0.1 DB5.DBX0.1 Boolean Bit 1 of byte 0 of DB 5
    DB23,B1 or DB23,BYTE1 DB23.DBB1 Number Byte 1 (0-255) of DB 23
    DB100,C2 or DB100,CHAR2 DB100.DBB2 String Byte 2 of DB 100 as a Char
    DB42,I3 or DB42,INT3 DB42.DBW3 Number Signed 16-bit number at byte 3 of DB 42
    DB57,WORD4 DB57.DBW4 Number Unsigned 16-bit number at byte 4 of DB 57
    DB13,DI5 or DB13,DINT5 DB13.DBD5 Number Signed 32-bit number at byte 5 of DB 13
    DB19,DW6 or DB19,DWORD6 DB19.DBD6 Number Unsigned 32-bit number at byte 6 of DB 19
    DB21,R7 or DB21,REAL7 DB21.DBD7 Number Floating point 32-bit number at byte 7 of DB 21
    DB2,S7.10* - String String of length 10 starting at byte 7 of DB 2
    I1.0 or E1.0 I1.0 or E1.0 Boolean Bit 0 of byte 1 of input area
    Q2.1 or A2.1 Q2.1 or A2.1 Boolean Bit 1 of byte 2 of output area
    M3.2 QM3.2 Boolean Bit 2 of byte 3 of memory area
    IB4 or EB4 IB4 or EB4 Number Byte 4 (0 -255) of input area
    QB5 or AB5 QB5 or AB5 Number Byte 5 (0 -255) of output area
    MB6 MB6 Number Byte 6 (0 -255) of memory area
    IC7 or EC7 IB7 or EB7 String Byte 7 of input area as a Char
    QC8 or AC8 QB8 or AB8 String Byte 8 of output area as a Char
    MC9 MB9 String Byte 9 of memory area as a Char
    II10 or EI10 IW10 or EW10 Number Signed 16-bit number at byte 10 of input area
    QI12 or AI12 QW12 or AW12 Number Signed 16-bit number at byte 12 of output area
    MI14 MW14 Number Signed 16-bit number at byte 14 of memory area
    IW16 or EW16 IW16 or EW16 Number Unsigned 16-bit number at byte 16 of input area
    QW18 or AW18 QW18 or AW18 Number Unsigned 16-bit number at byte 18 of output area
    MW20 MW20 Number Unsigned 16-bit number at byte 20 of memory area
    IDI22 or EDI22 ID22 or ED22 Number Signed 32-bit number at byte 22 of input area
    QDI24 or ADI24 QD24 or AD24 Number Signed 32-bit number at byte 24 of output area
    MDI26 MD26 Number Signed 32-bit number at byte 26 of memory area
    ID28 or ED28 ID28 or ED28 Number Unsigned 32-bit number at byte 28 of input area
    QD30 or AD30 QD30 or AD30 Number Unsigned 32-bit number at byte 30 of output area
    MD32 MD32 Number Unsigned 32-bit number at byte 32 of memory area
    IR34 or ER34 IR34 or ER34 Number Floating point 32-bit number at byte 34 of input area
    QR36 or AR36 QR36 or AR36 Number Floating point 32-bit number at byte 36 of output area
    MR38 MR38 Number Floating point 32-bit number at byte 38 of memory area
    DB1,DT0 - Date** A timestamp in the DATE_AND_TIME format
    DB1,DTZ10 - Date** A timestamp in the DATE_AND_TIME format, in UTC
    DB2,DTL2 - Date** A timestamp in the DTL format
    DB2,DTLZ12 - Date** A timestamp in the DTL format, in UTC
    • *) Note that strings on the PLC uses 2 extra bytes at start for size/length of the string
    • **) Note that javascript's Date are always represented in UTC. Please use other nodes like node-red-contrib-moment to properly handle type conversions

    Notes on S7-1200/1500

    These newer PLCs offer an "extended" version of the S7 Protocol, while we have only a "basic" version of it.

    Therefore, some additional configuration steps on the PLC are necessary:

    • "Optimized block access" must be disabled for the DBs we want to access (image)
    • In the "Protection" section of the CPU Properties, enable the "Permit access with PUT/GET" checkbox (image)

    Notes on Logo! 8

    On the newest Logo! 8.FS4 (and possibly 0BA8) Logic modules there is no need to set the Mode to TSAP any more, instead the default Rack/Slot value of 0/2 works just fine.

    The following table shows memory areas accessible without additional settings in the controller program:

    Note: These memory areas seem to be read-only from outside the controller, as they are directly used by the function blocks listed in "Logo Block" of the table

    Logo Block Logo VM Range example Node-RED address Description
    I 1024 - 1031 DB1,BYTE1024 or DB1,X1024.5 or DB1,WORD1024 Reads input terminals 1...8 or 6 or 1...16
    AI 1032 - 1063 DB1,WORD1032 Reads analog input terminal 1. Always word sized.
    Q 1064 - 1071 DB1,BYTE1064 or DB1,X1064.5 or DB1,WORD1064 Reads output terminals 1...8 or 6 or 1...16
    AQ 1072 - 1103 DB1,WORD1072 Reads analog output terminal 1. Always word sized.
    M 1104 - 1117 DB1,BYTE1104 or DB1,X1104.5 or DB1,WORD1104 Reads bit flags M1...M8 or M6 or M1...16
    AM 1118 - 1245 DB1,WORD1118 Reads analog flag 1. Always word sized.
    NI 1246 - 1061 DB1,BYTE1246 or DB1,X1246.5 or DB1,WORD1246 Reads network input 1...8 or 6 or 1...16
    NAI 1262 - 1389 DB1,WORD1262 Reads analog network input 1. Always word sized.
    NQ 1390 - 1405 DB1,BYTE1390 or DB1,X1390.5 or DB1,WORD1390 Reads network output 1...8 or 6 or 1...16
    NAQ 1406 - 1469 DB1,WORD1406 Reads network output 1. Always word sized.

    On the other hand, Logo memory areas VM 0-849 are mutable from outside the controller, but they need to be mapped into the Logo program. Without mapping, data written into these addresses will have no effect on program execution. Used VM addresses in the range mentioned above can be read/written from/into in the Logo program using the "Network" function blocks (in the function block setup use the "Local variable memory (VM)" option to map VMs to the function block).

    Some addressing examples:

    Logo VM Example Node-RED address Description
    0 DB1,BYTE0 R/W access
    1 DB1,X1.3 R/W access Note: use booleans
    2..3 DB1,WORD2 R/W access
    4..7 DB1,DWORD4 R/W access

    Bugs and enhancements

    Please share your ideas and experiences on the Node-RED forum, or open an issue on the page of the project on GitHub

    Support

    Community support is offered on a best-effort basis via GitHub Issues. For commercial support, please contact us by sending an e-mail to st-one@st-one.io.

    License

    Copyright: (c) 2016-2020, ST-One Ltda., Guilherme Francescon Cittolin guilherme@st-one.io

    GNU General Public License v3.0+ (see LICENSE or https://www.gnu.org/licenses/gpl-3.0.txt)

    Install

    npm i node-red-contrib-s7

    DownloadsWeekly Downloads

    592

    Version

    3.0.0

    License

    GPL-3.0-or-later

    Unpacked Size

    166 kB

    Total Files

    12

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