Modbus exporter

Prometheus exporter which retrieves stats from a modbus tcp system and exports them via HTTP for Prometheus consumption.

Reproduce diagram

Go to: https://bramp.github.io/js-sequence-diagrams/

Note right of Prometheus: promehteus.yml \n --- \n target: Modbus-TCP-10.0.0.5 \n sub_target: Modbus-Unit-10 \n module: VendorXY
Prometheus->Exporter: http://xxx.de/metrics?target=10.0.0.5&sub_target=10&module=vendorxy
Note right of Exporter: modbus.yml \n --- \n module: VendorXY \n - temperature_a: 400001 \n - temperature_b: 400002

Exporter->Modbus_TCP_10.0.0.5: tcp://10.0.0.5?unit=10&register=400001
Modbus_TCP_10.0.0.5->Modbus_RTU_10: rtu://_?register=400001
Modbus_RTU_10-->Modbus_TCP_10.0.0.5: value=20
Modbus_TCP_10.0.0.5-->Exporter: value=20

Exporter->Modbus_TCP_10.0.0.5: tcp://10.0.0.5?unit=10&register=400002
Modbus_TCP_10.0.0.5->Modbus_RTU_10: rtu://_?register=400002
Modbus_RTU_10-->Modbus_TCP_10.0.0.5: value=19
Modbus_TCP_10.0.0.5-->Exporter: value=19

Exporter-->Prometheus:temperature_a{module="VendorXY",sub_target="10"} 20 \ntemperature_b{module="VendorXY",sub_target="10"} 19

Building

make build

Getting Started

The modbus exporter needs to be passed the target and module as parameters by Prometheus, this can be done with relabelling (see prometheus.yml).

Once Prometheus is properly configured, run the exporter via:

./modbus_exporter [flags]

Supported flags:

Usage of ./modbus_exporter:
  -config.file string
    	Sets the configuration file. (default "modbus.yml")
  -modbus-listen-address string
    	The address to listen on for HTTP requests exposing modbus metrics. (default ":9602")
  -telemetry-listen-address string
    	The address to listen on for HTTP requests exposing telemetry metrics about the exporter itself. (default ":9602")

Visit http://localhost:9602/modbus?target=1.2.3.4 where 1.2.3.4 is the IP of the modbus IP device to get metrics from. You can also specify a module and a sub_target parameter, to choose which module and subtarget to use from the config file.

Visit http://localhost:9602/metrics to get the metrics of the exporter itself.

Configuration File

Check out modbus.yml for more details on the configuration file format.

TODO

• Rework logging.

• Revisit bit parsing.

• Print name, version, ... on exporter startup.

Misc info

ModBus RTU

Support for serial ModBus (RTU) was dropped in git commit d06573828793094fd2bdf3e7c5d072e7a4fd381b. Please send a PR if you need it again. For now, we suggest using a ModBus PLC/bridge/master to bridge from RTU into TCP.

Forking information

This is forked from https://github.com/lupoDharkael/modbus_exporter which was not maintained any more and did not follow Prometheus best practices. Initially, development happened in https://github.com/mxinden/modbus_exporter which has now been retired in favour of https://github.com/RichiH/modbus_exporter .