*) Note that strings on the PLC uses 2 extra bytes at start for size/length of the string.Unsigned 16-bit number at byte 20 of memory area, interpreted as Little-Endian Signed 32-bit number at byte 5 of DB 13, interpreted as Little-Endian Unsigned 16-bit number at byte 4 of DB 57, interpreted as Little-Endian Unsigned 32-bit number at byte 32 of memory areaįloating point 32-bit number at byte 34 of input areaįloating point 32-bit number at byte 36 of output areaįloating point 32-bit number at byte 38 of memory areaĪ timestamp in the DATE_AND_TIME format, in UTC Unsigned 32-bit number at byte 30 of output area Unsigned 32-bit number at byte 28 of input area Signed 32-bit number at byte 26 of memory area

Signed 32-bit number at byte 24 of output area Signed 32-bit number at byte 22 of input area Unsigned 16-bit number at byte 20 of memory area Unsigned 16-bit number at byte 18 of output area Unsigned 16-bit number at byte 16 of input area Signed 16-bit number at byte 14 of memory area Signed 16-bit number at byte 12 of output area Signed 16-bit number at byte 10 of input area String of length 10 starting at byte 7 of DB 2 Unsigned 32-bit number at byte 6 of DB 19įloating point 32-bit number at byte 7 of DB 21 Unsigned 16-bit number at byte 4 of DB 57 Here are some examples that may guide you on addressing your variables: Address The variables and their addresses configured on the S7 Endpoint follow a slightly different scheme than used on Step 7 or TIA Portal. If diff is checked, a message is sent if at least one of the variables changes its value. All variables: In this mode, msg.payload contains an object with all configured variables and their values.

Care must be taken about the number of messages per second in this mode. If diff is unchecked, one message is sent for every variable, in every cycle. If diff is checked, a message is sent everytime any variable changes.

All variables, one per message: Like the Single variable mode, but for all variables configured.

msg.payload contains the variable's value and msg.topic has the variable's name.

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.

The S7 In node makes the variable's values available in a flow in three different modes: You can configure the PLC's Address, the variables available and their addresses, and the cycle time for reading the variables. UsageĮach connection to a PLC is represented by the S7 Endpoint configuration node. NodeJS version 10 or greater and Node-RED version 1.0 or greater is required.

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