S7comm

S7comm is a telegraf external input plugin to gather data from Siemens PLC using the gos7 library.

Installation

Download the repo

git clone git@github.com:nicolasme/s7comm.git

Change the poll interval if needed in the cmd/main.go file

var pollInterval = flag.Duration("poll_interval", 10*time.Second, "how often to send metrics")

Build the binary

go build -o s7comm cmd/main.go

Create your plugin.config file

[[inputs.s7comm]]
	name = "S7300"
	plc_ip = "192.168.10.57"
	plc_rack = 0
	plc_slot = 1
    	connect_timeout = "10s"
    	request_timeout = "2s"
    	nodes = [{name= "test_int", address= "DB1.DBW0", type = "int"},
        	{name= "test_real", address= "DB1.DBD2",type = "real"},
        	{name= "test_bool", address= "DB1.DBX10.0",type = "bool"},
        	{name= "test_dint", address= "DB1.DBD12",type = "dint"},
        	{name= "test_uint", address= "DB1.DBW16",type = "uint"},
        	{name= "test_udint", address= "DB1.DBD18",type = "udint"}]

From here, you can already test the plugin with your config file.

s7comm -config plugin.conf

If everything is ok, you should see something like this

2021/06/09 10:37:27 I! Connexion successfull
test_int value=8056i 1623227848846884706
test_real value=403.14764404296875 1623227849849296642

Datatypes

You have to specifie the data type in your config file for each node. At the moment, only those types are implemented :

bool, byte, word, dword, int, dint, uint, udint, real, time

Telegraf configuration

To use the plugin with telegraf, add this configuration to your main telegraf.conf file. S7comm is an external plugin using shim and execd. Go see their doc for more information.

[[inputs.execd]]
  command = ["/path/to/s7comm", "-config", "/path/to/s7comm.plugin.conf"]
  signal = "none"
  restart_delay = "10s"
  data_format = "influx"

PLC configuration

S7-300 and S7-400 usually use rack 0 and slot 2 and dont require additional configuration.

S7-1200 and S7-1500 usually use rack 0 and slot 1 and you need to enable the PUT/GET operations in the hardware configuration of your PLC and you have to set DBs as non-optimized.

Be aware of security issue. Once S7 Communication is enabled in a CPU, there is no way to block communication with a partner device. This means that any device on the same network can read and write data to the CPU using the S7 Communication protocol. For this reason, I would recommend using the native OPC.UA server for the newer S7-1200 and S7-1500 PLCs. See the OPC.UA telegraf plugin.

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

MIT