====== [ST] Custom serial protocol ======
#;;
Patron
Neuron
Gate
Unipi 1.1
Axon
#;;
When implementing the system, it is sometimes necessary to use a protocol that is not available in the Mervis environment. Such a situation can occur, for example, when you install a Unipi PLC as a replacement for another PLC and you need to connect some of the original peripherals, or when you need to connect the Unipi PLC to your own device with its own protocol.
The following article describes the basic information needed to successfully implement a custom serial protocol and a sample project.
Prerequisites:
* Unipi controller running [[en:files:software:os-images:00-start|Mervis OS]] and [[en:files:software:mervis:00-start|Mervis IDE]] version 2.4.2 or higher
* [[https://www.unipi.technology/en/accessories-c4|24 V⎓ power supply]]
* local network connectivity (any switch or router)
* Basic knowledge of programming in structured text (ST)
===== Preparation of the solution =====
Since the implementation of a serial protocol with a function block diagram (FBD) is more demanding and complex than the implementation in structured text (ST), we recommend the implementation in the ST language.
In order to create programs, functions or function blocks in the ST language, it is first necessary to switch the solution to [[en:sw:01-mervis:creating-new-project-hidden#switching_to_full_mode|full mode]].
===== Available functions in Mervis =====
A total of 5 functions for working with (serial) ports are available in Mervis:
- **Open Port** - opens a port communication according to the entered data
- **Get Port Status** - gets the communication status of a handle
- **Write Port** - writes data to a given communication port
- **Read Port** - reads data from a given communication port
- **Close Port** - closes communication at the given port
A description of the inputs and outputs of the above functions is available in the Mervis IDE help \\
(path: Software -> Libraries -> Communications -> Input/Output Functions)
===== Sample project =====
As part of the sample project, a state machine is implemented for communication via the selected serial port on the query/response principle, when a response is expected after sending a query. Therefore, this sample project does not include a state machine that expects a spontaneous flow of data from a remote device.
A table of serial ports is also implemented (according to the tables below) using derived data types (structures) and an HMI web interface simulating a terminal window for simple communication test.
{{.:custom-serial-protocol:240924_web_serial_terminal_ide265.zip|The sample project of custom serial protocol}}
The project is created in Mervis IDE 2.6.5.
===== Marking of Unipi serial ports in ST language =====
Since Mervis IDE 2.6.5 the serial port table (structure) is included in Lib.Unipi, which allows easy selection by controller type.
=== Example of use: ===
FUNCTION_BLOCK Custom_Serial
VAR
serialPort : unipi_serial.v1_0.Patron_M567;
str,def : string;
END_VAR
INIT
def := 'serial:'; // the first part of the definition
def := CONCAT(IN1:=def,IN2:=serialPort.RS485_1_1); // merge the first part of the definition with the serial port
def := CONCAT(IN1:=def,IN2:=':9600,8,N,1'); //merge with the last part of the definition
END_INIT
str := serialPort.RS485_1_1;
END_FUNCTION_BLOCK
==== Unipi Edge ====
|< 100% 20% 40% 40%>|
^ ^RS485-S1 ^RS232-S2 ^
|E410|1|2|
|E411|1|-|
|E412|1|2|
|E413|1|2|
=== Common ===
|< 100% 20% 80% >|
|USB1|10|
|USB2|11|
|< 100% 20% 80% >|
|LTE|20|
|< 100% 20% 80% >|
|M-Bus M1|30|
|M-Bus M2|31|
==== Unipi Patron ====
|< 100% 20% 20% 20% 20% 20%>|
^ ^RS485-1 ^RS232(485)-2 ^RS485-3 ^RS485-4 ^
|S107|6|2|1|-|
|S117|6|3|2|1|
|S167 LTE|6|1|-|-|
|S207|1|-|-|-|
|< 100% 20% 20% 20% 20% 20%>|
^ ^RS485-1.1 ^RS232(485)-1.2 ^RS485-1.3 ^RS485-2.1 ^
|M207|6|2|1|-|
|M267 LTE|6|1|-|-|
|M527|6|2|1|7|
|M537|6|2|1|7|
|M567 LTE|6|1|-|7|
|L207|6|2|1|-|
|L527|6|2|1|7|
=== Common ===
|< 100% 20% 80% >|
|USB1|10|
|USB2|11|
|< 100% 20% 80% >|
|LTE|20|
==== Unipi Neuron ====
|< 100% 20% 26.6% 26.6% 26.6%>|
^ ^RS485-1.1 ^RS485-2.1 ^RS485-3.1 ^
|S103 |6 |- |- |
|S103-G |6 |- |- |
|M103 |6 |- |- |
|M203 |6 |- |- |
|M303 |6 |- |- |
|M403 |6 |- |- |
|M503 |6 |7 |- |
|M523 |6 |7 |- |
|L203 |6 |- |- |
|L303 |6 |- |- |
|L403 |6 |- |- |
|L503 |6 |7 |- |
|L523 |6 |7 |- |
|L513 |6 |7 |8 |
|L533 |6 |7 |8 |
=== Common ===
|< 100% 20% 80% >|
| USB1 | 10 |
| USB2 | 11 |
| USB3 | 12 |
| USB4 | 13 |
|< 100% 20% 80% >|
|GSM|1|
==== Unipi Gate ====
|< 100% 20% 40% 40%>|
^ ^RS485-1 ^RS485-2 ^
|G100|2|-|
|G110|2|3|
=== Common ===
|< 100% 20% 80% >|
| USB | 10 |
==== Unipi 1.1 / Lite====
|< 100% 20% 80% >|
| UART | 1 |
|< 100% 20% 80% >|
| USB1 | 10 |
| USB2 | 11 |
| USB3 | 12 |
| USB4 | 13 |
==== Unipi Axon ====
|< 100% 20% 20% 20% 20% 20%>|
^ ^RS485-1 ^RS232(485)-2 ^RS485-3 ^RS485-4 ^
|S105|6|3|2|-|
|S115|6|1|3|2|
|S155|6|3|2|-|
|S165 LTE|6|2|-|-|
|S205|2|-|-|-|
|S215|2|3|-|-|
|S505|2|-|-|-|
|S515|2|3|-|-|
|< 100% 20% 20% 20% 20% 20%>|
^ ^RS485-1.1 ^RS232(485)-1.2 ^RS485-1.3 ^RS485-2.1 ^
|M205|6|3|2|-|
|M265 LTE|6|2|-|-|
|M505|6|3|2|7|
|M515|2|3|-|6|
|M525|6|3|2|7|
|M535|2|3|-|6|
|M565 LTE|6|2|-|7|
|L205|6|3|2|-|
|L505|6|3|2|7|
|L525|6|3|2|7|
=== Common ===
|< 100% 20% 80% >|
|USB1|10|
|USB2|11|
|< 100% 20% 80% >|
|LTE|20|
/* https://kb.unipi.technology/cs:sw:01-mervis:serial-port-numbers-hidden */