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Obsidean_VM/01-Documentation/Dispositivos - Manuales/ADAM/Maselli Sensor to Siemens P...

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## Introduction
This document provides an implementation guide for establishing communication between a Maselli sensor (which uses the ADAM protocol over RS485) and a Siemens S7-315 DP/PN PLC using a Waveshare RS232/485 TO WIFI ETH (B) gateway. This implementation handles the unidirectional communication where data flows from the sensor to the PLC.
## Maselli Protocol with ADAM Overview
As per the provided documentation, the Maselli sensor communicates with the following characteristics:
- **Maselli UR29**: RS485 with 115200 baud, 8N1 settings
- **Maselli UR62**: RS485 with 19200 baud, 8N1 settings
- **Communication Type**: Unidirectional (sensor sends data to PLC)
- **Data Format**: String with specific format:
```
# XX XX.YYY CkCk Cr
```
Where:
- `#` is the start character
- `XX` is the ADAM address (2 chars)
- `XX.YYY` is the Brix or Temperature value in mA (6 chars)
- `CkCk` is the checksum (2 chars)
- `Cr` is the carriage return
- **Value Range Example**:
- 4 mA corresponds to Low Brix value (e.g., 0 Brix)
- 20 mA corresponds to High Brix value (e.g., 80 Brix)
## SCL Implementation
The following SCL code provides a complete implementation for handling this communication. The implementation consists of multiple parts:
1. A function block for managing TCP/IP communication with the gateway
2. Functions for parsing the Maselli protocol string
3. Functions for scaling the mA value to the appropriate Brix value
4. Configuration functions for the TCP connection
### Main Function Block
```scl
FUNCTION_BLOCK "FB_Maselli_Communications"
VAR_INPUT
xExecute : BOOL; // Trigger to initiate connection
tConnectionID : TCON_IP_v4; // TCP connection parameters
END_VAR
VAR_OUTPUT
xConnected : BOOL; // Connection status
xError : BOOL; // Communication error
wErrorID : WORD; // Error code
rBrixValue : REAL; // Calculated Brix value
rTempValue : REAL; // Calculated Temperature value (if applicable)
rCurrentmA : REAL; // Received mA value
END_VAR
VAR
// TCP communication variables
fbTCON : TCON; // FB for TCP connection
fbTRCV : TRCV; // FB for TCP reception
xTCONExecute : BOOL;
xTRCVExecute : BOOL;
wTCONID : WORD := 1; // Connection ID
// Buffer and processing variables
aRxBuffer : ARRAY[0..255] OF BYTE; // Reception buffer
iRxLength : INT; // Received length
sRxString : STRING[255]; // Reception string
sParsedValue : STRING[6]; // Extracted value as string (XX.YYY)
// Parsing variables
iState : INT := 0; // Parsing state
xNewDataReceived : BOOL := FALSE; // New data flag
// Scaling variables
rLowBrix : REAL := 0.0; // Low Brix value (4mA)
rHighBrix : REAL := 80.0; // High Brix value (20mA)
END_VAR
VAR CONSTANT
START_CHAR : BYTE := 16#23; // '#' in ASCII
END_VAR
BEGIN
// ---- TCP Connection Management ----
IF xExecute AND NOT xConnected THEN
xTCONExecute := TRUE;
END_IF;
// Establish connection
fbTCON(
EN := TRUE,
ENO => ,
REQ := xTCONExecute,
ID := wTCONID,
CONNECT := tConnectionID,
DONE => xConnected,
BUSY => ,
ERROR => xError,
STATUS => wErrorID
);
// Reset connection trigger
IF xConnected OR xError THEN
xTCONExecute := FALSE;
END_IF;
// ---- Data Reception ----
IF xConnected THEN
xTRCVExecute := TRUE;
// Receive data
fbTRCV(
EN := TRUE,
ENO => ,
REQ := xTRCVExecute,
ID := wTCONID,
LEN := 0, // Adhoc mode (receives whatever is available)
DATA := aRxBuffer,
RCVD_LEN => iRxLength,
DONE => xNewDataReceived,
BUSY => ,
ERROR => xError,
STATUS => wErrorID
);
// Process received data
IF xNewDataReceived AND iRxLength > 0 THEN
// Convert data to string for processing
sRxString := '';
FOR i := 0 TO iRxLength-1 DO
sRxString := CONCAT(IN1 := sRxString,
IN2 := CHR(IN := aRxBuffer[i]));
END_FOR;
// Process Maselli/ADAM protocol
ParseMaselliString(sRxString);
// Calculate Brix value based on mA value (linear scale)
rBrixValue := LinearScale(rCurrentmA, 4.0, 20.0, rLowBrix, rHighBrix);
// Reset flag
xNewDataReceived := FALSE;
END_IF;
END_IF;
END_FUNCTION_BLOCK
```
### Parsing Function
```scl
// Function to process the received Maselli/ADAM string
FUNCTION "ParseMaselliString" : VOID
VAR_INPUT
sInputString : STRING;
END_VAR
VAR_TEMP
sCurrentChar : STRING(1);
iPos : INT := 0;
iParseState : INT := 0; // 0:Waiting for #, 1:Reading addr, 2:Reading value, 3:Reading checksum
sAddrStr : STRING(2);
sValueStr : STRING(6);
sChecksumStr : STRING(2);
END_VAR
BEGIN
// Reset variables
sAddrStr := '';
sValueStr := '';
sChecksumStr := '';
// Parse the string character by character
FOR iPos := 0 TO LEN(sInputString) - 1 DO
sCurrentChar := MID(IN := sInputString, L := 1, P := iPos + 1);
CASE iParseState OF
0: // Waiting for start character '#'
IF sCurrentChar = '#' THEN
iParseState := 1;
END_IF;
1: // Reading ADAM address (2 characters)
sAddrStr := CONCAT(IN1 := sAddrStr, IN2 := sCurrentChar);
IF LEN(sAddrStr) = 2 THEN
iParseState := 2;
END_IF;
2: // Reading mA value (6 characters, format XX.YYY)
sValueStr := CONCAT(IN1 := sValueStr, IN2 := sCurrentChar);
IF LEN(sValueStr) = 6 THEN
iParseState := 3;
// Convert string to real value
#rCurrentmA := STRING_TO_REAL(sValueStr);
END_IF;
3: // Reading checksum (2 characters)
sChecksumStr := CONCAT(IN1 := sChecksumStr, IN2 := sCurrentChar);
// Checksum validation not implemented in this simplified example
END_CASE;
END_FOR;
END_FUNCTION
```
### Scaling Function
```scl
// Function to linearly scale the mA value to Brix
FUNCTION "LinearScale" : REAL
VAR_INPUT
rInput : REAL; // Value to scale (mA)
rInMin : REAL; // Input minimum (4mA)
rInMax : REAL; // Input maximum (20mA)
rOutMin : REAL; // Output minimum (0 Brix)
rOutMax : REAL; // Output maximum (80 Brix)
END_VAR
BEGIN
// Linear scaling formula
#LinearScale := (rInput - rInMin) * (rOutMax - rOutMin) / (rInMax - rInMin) + rOutMin;
// Ensure result is within limits
IF #LinearScale < rOutMin THEN
#LinearScale := rOutMin;
ELSIF #LinearScale > rOutMax THEN
#LinearScale := rOutMax;
END_IF;
END_FUNCTION
```
### Main Application Block
```scl
// Main application block
ORGANIZATION_BLOCK "OB1"
VAR_TEMP
// Temporary variables
END_VAR
BEGIN
// Configure TCP connection
"ConfigureTCPConnection"();
// Process Maselli data
"FB_Maselli_Communications"(
xExecute := TRUE,
tConnectionID := "g_tConnection"
);
// Additional code to use Brix values can be added here
END_ORGANIZATION_BLOCK
```
### Connection Configuration Function
```scl
// Function to configure TCP connection parameters
FUNCTION "ConfigureTCPConnection" : VOID
VAR_GLOBAL
g_tConnection : TCON_IP_v4; // Global variable for connection parameters
END_VAR
BEGIN
// Configure TCP connection parameters
g_tConnection.InterfaceId := 64; // Ethernet interface ID (verify in hardware)
g_tConnection.ID := 1; // Connection ID
g_tConnection.ConnectionType := 11; // Connection type: TCP
g_tConnection.ActiveEstablished := TRUE; // PLC initiates connection
// IP and port of Waveshare gateway
g_tConnection.RemoteAddress.ADDR[1] := 192; // IP Address: 192.168.x.x
g_tConnection.RemoteAddress.ADDR[2] := 168; // Adjust according to gateway IP
g_tConnection.RemoteAddress.ADDR[3] := 1; // Adjust according to gateway IP
g_tConnection.RemoteAddress.ADDR[4] := 10; // Adjust according to gateway IP
g_tConnection.RemotePort := 8899; // Default gateway port
// Local port for TCP connection
g_tConnection.LocalPort := 2000; // Arbitrary local port
END_FUNCTION
```
## Configuration Guide
To implement this solution, follow these steps:
### 1. Configure the Waveshare Gateway
Configure the Waveshare RS232/485 TO WIFI ETH (B) gateway in transparent transmission mode with these parameters:
- **For UR29 sensor**:
- RS485: 115200 baud, 8N1
- TCP Server mode (recommended)
- Fixed IP address on your network
- **For UR62 sensor**:
- RS485: 19200 baud, 8N1
- TCP Server mode (recommended)
- Fixed IP address on your network
### 2. PLC Configuration
- Import the SCL code into your TIA Portal project
- Adjust the IP address settings in the `ConfigureTCPConnection` function to match your gateway's IP
- Modify the `rLowBrix` and `rHighBrix` values according to your specific application requirements
- Configure the Ethernet port of the S7-315 PLC to be on the same subnet as the gateway
### 3. Verification
After implementing the code:
- Monitor the `xConnected` output to verify the connection status
- Check the `rBrixValue` output to see the converted Brix values
- Use the `xError` and `wErrorID` outputs for troubleshooting if connection issues occur
## Additional Notes
- This implementation focuses on handling the reception of data in the specified Maselli/ADAM format
- The checksum validation is not implemented in this example but could be added for improved reliability
- For optimal performance, ensure the network connection between the PLC and the gateway is stable
- Consider adding watchdog functionality to detect communication failures
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