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Snapex7 is an Elixir wrapper for the Snap7 library. Snap7 i san open source, 32/64 bit, multi-platform Ethernet communication suite for interfacing natively with Siemens S7 PLCs (See [Target Compatibility](#target-compatibility)).
* Snapex7 is developer for snap7 1.4.2 and Elixir 1.8.1. It is tested on:
* Ubuntu
* MacOS
* Nerves
* **Note** Currently only the **Client implementation as synchronous** of Snap7 is available. Future implementations can be found in our [TODO](#todo) section.
## Content
* [Installation](#installation)
* [Target Compatibility](#target-compatibility)
* [Using Snapex7](#using-snapex7)
* [Connection functions](#connection-functions)
* [Data IO functions](#data-io-functions)
* [Error format](#error-format)
* [Types](#types)
* [Further Documentation and Examples](#further-documentation-and-examples)
* [Contributing to this Repo](#contributing-to-this-repo)
* [TODO](#todo)
## Installation
The package can be installed by adding `snapex7` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:snapex7, "~> 0.1.2"}
]
end
```
Fetch the dependency by running `mix deps.get` in your terminal.
## Target Compatibility
Many hardware components equipped with an Ethernet port can communicate via the S7 protocol.
Check compatibility with the component that you are using:
* **Snap7** full compatibility documentation can be found at pg.33 [Snap7-refman.pdf](https://github.com/valiot/snap7/blob/a1845454f5f16f3b127b987807f1cbc59205db70/doc/Snap7-refman.pdf)
Here is a summary compatibility table from the documentation above:
<img src="https://raw.githubusercontent.com/valiot/snapex7/master/assets/images/compatibility.png" alt="Compatibility" />
## Using Snapex7
Start a `Snapex7.Client` and connect it to the PLC's IP, where:
* **port**: C port process
* **controlling_process**: where events get sent
* **queued_messages**: queued messages when in passive mode **(WIP)**.
* **ip**: the address of the server
* **rack**: the rack of the server.
* **slot**: the slot of the server.
* **is_active**: active or passive mode **(WIP)**.
```elixir
iex> {:ok, pid} = Snapex7.Client.start_link()
iex> Snapex7.Client.connect_to(pid, ip: "192.168.0.1", rack: 0, slot: 1)
```
### Connection functions
* **Connect to a S7 server**.
The following options are available:
* `:active` - (`true` or `false`) specifies whether data is received as
messages or by calling "Data I/O functions".
* `:ip` - (string) PLC/Equipment IPV4 Address (e.g., "192.168.0.1")
* `:rack` - (int) PLC Rack number (0..7).
* `:slot` - (int) PLC Slot number (1..31).
```elixir
iex> :ok = Snapex7.Client.connect_to(pid, ip: "192.168.0.1", rack: 0, slot: 1)
```
* **Disconnects** gracefully the Client from the PLC.
```elixir
iex> :ok = Snapex7.Client.disconnect(pid)
```
* **Get connected** returns the connection status.
```elixir
iex> {:ok, boolean} = Snapex7.Client.get_connected(pid)
```
### Data IO functions
* **Reads a data area** from a PLC.
The following options are available:
* `:area` - (atom) Area Identifier. See [@area_types](#types).
* `:db_number` - (int) DataBase number, if `area: :DB` otherwise is ignored.
* `:start` - (int) An offset to start.
* `:amount` - (int) Amount of words to read/write.
* `:word_len` - (atom) Word size See [@word_types](#types).
```elixir
iex> {:ok, resp_binary} =
Snapex7.Client.read_area(pid,
area: :DB,
word_len: :byte,
start: 2,
amount: 4,
db_number: 1
)
```
* **Write a data area** from a PLC..
The same options of `Snapex.Client.read_area` are available here plus:
* `:data` - (atom) buffer to write.
```elixir
iex> :ok =
Snapex7.Client.write_area(pid,
area: :DB,
word_len: :byte,
start: 2,
amount: 4,
db_number: 1,
data: <<0x42, 0xCB, 0x00, 0x00>>
)
```
* Lean functions of `Snapex.Client.read_area` and `Snapex.Client.write_area` for different types of ... are implemented:
* `db_read` & `db_write`: for PLC Database.
* `ab_read` & `ab_write`: for PLC process outputs.
* `eb_read` & `eb_write`: for PLC process inputs.
* `mb_read` & `mb_write`: for PLC merkers.
* `tm_read` & `tm_write`: for PLC timers.
* `ct_read` & `ct_write`: for PLC counters.
* **Write and Read different kinds of variables** from a PLC in a single call. It can do so with it can read DB, inputs, outputs, Merkers, Timers and Counters.
```elixir
iex> data1 = %{
area: :DB,
word_len: :byte,
db_number: 1,
start: 2,
amount: 4,
data: <<0x42, 0xCB, 0x20, 0x10>>
}
iex> data2 = %{
area: :PA,
word_len: :byte,
db_number: 1,
start: 0,
amount: 1,
data: <<0x0F>>
}
iex> r_data1 = %{
area: :DB,
word_len: :byte,
db_number: 1,
start: 2,
amount: 4
}
iex> r_data2 = %{
area: :PA,
word_len: :byte,
db_number: 1,
start: 0,
amount: 1
}
iex> :ok = Snapex7.Client.write_multi_vars(pid, data: [data1, data2])
iex> {:ok, [binary]} = Snapex7.Client.read_multi_vars(pid, data: [r_data1, r_data2])
```
### Error format
When a response returns an error, it will have the following format:
```elixir
iex> {:error, %{eiso: nil, es7: nil, etcp: 113}}
```
* **eiso**: returns an atom with the ISO TCP error.
* **es7**: returns an atom with the S7 protocol error.
* **etcp**: returns an int TCP error or nil (Depends on your OS). Example: see [TCP_error_info](https://gist.github.com/gabrielfalcao/4216897) for Ubuntu OS.
See [Snap7-refman.pdf](https://github.com/valiot/snap7/blob/a1845454f5f16f3b127b987807f1cbc59205db70/doc/Snap7-refman.pdf) pg.252 for further error info.
### Types
Arguments definition for each particular memory block:
```elixir
@block_types [
OB: 0x38, # Organization block
DB: 0x41, # Data block
SDB: 0x42, # System data block
FC: 0x43, # Function
SFC: 0x44, # System function
FB: 0x45, # Functional block
SFB: 0x46 # System functional block
]
@connection_types [
PG: 0x01, # Programming console
OP: 0x02, # Siemens HMI panel
S7_basic: 0x03 # Generic data transfer connection
]
@area_types [
PE: 0x81, # Process Inputs
PA: 0x82, # Process Outputs
MK: 0x83, # Merkers
DB: 0x84, # DB
CT: 0x1C, # Counters
TM: 0x1D # Timers
]
@word_types [
bit: 0x01,
byte: 0x02,
word: 0x04,
d_word: 0x06,
real: 0x08,
counter: 0x1C,
timer: 0x1D
]
```
## Further documentation and examples
Snapex7 has further client functions implementation which can be found at [Snapex7 Hexdocs](https://hexdocs.pm/snapex7).
* Client function types in [Hexdocs](https://hexdocs.pm/snapex7):
* Administrative
* Data IO
* Directory
* Block oriented
* Date/Time
* System Info
* PLC Control
* Security
* Low level
* Miscellaneous
* **Additional examples of usage** can be found in the testing section of the project
[/test/s7_client_text/](https://github.com/valiot/snapex7/tree/master/test/s7_client_test)
* **Note**: Tests where writen with a local preconfigured PLC.
* **Snap7** source code and documentation can be found at [Snap7-refman.pdf](https://github.com/valiot/snap7/blob/a1845454f5f16f3b127b987807f1cbc59205db70/doc/Snap7-refman.pdf)
## Contributing to this Repo
* Fork our repository on github.
* Fix or add what is needed.
* Commit to your repository
* Issue a github pullrequest.
If you wish to clone this Repo use:
```
git clone --recursive git@github.com:valiot/snap7.git
```
## License
See [LICENSE](./LICENSE).
## TODO
* **Better handling c code**
* **Server implementation**
* **Partner implementation**
* **Asynchronous Client implementation**
