Modbus Communication between Delta PLC and Adroit SCADA.
Introduction
A short write-up on how to connect a Delta PLC to Adroit SCADA via the Modbus Communication drivers.
Step by Step Procedure:
Step 1: Configure the Delta PLC for Modbus TCP
Set Up the PLC Ethernet Module
Connect the Delta PLC’s Ethernet module (e.g., DVP-EN01) to the PLC.
Use Delta’s WPLSoft or ISPSoft to configure the Ethernet module:
Open the software and connect to the PLC via RS-232 or another available interface.
Navigate to the Ethernet configuration section.
Assign a static IP address to the PLC (e.g., 192.168.1.100, subnet mask 255.255.255.0).
Set the port to 502 (default for Modbus TCP).
Configure the gateway if required (e.g., 192.168.1.1).
Save and download the configuration to the PLC.
Configure Modbus TCP Settings
Ensure the PLC is set to act as a Modbus TCP server (slave).
Set the PLC’s station ID (Modbus slave address) to a value between 1 and 254 (e.g., 1). Note that addresses above 254 require padding (see mod_eth.pdf, section 4.1).
Map the PLC’s internal devices (e.g., T, C, D registers) to Modbus addresses as per the DVP device address table:
Coils (S, Y, M, T, C): 0000–0FFF (hex)
Inputs (X, Y, M, T, C): 0400–0FFF (hex)
Holding Registers (T, C, D): 0600–1FFF (hex)
Example: T20 corresponds to holding register address 0614H (hex).
Verify PLC Program
Ensure the PLC program is running and that the registers/coils to be monitored or controlled are accessible.
Test the PLC’s Ethernet connectivity by pinging its IP address from the SCADA PC (e.g., ping 192.168.1.100).
Step 2: Set Up the Network
Connect Hardware:
Connect the PLC’s Ethernet module to the same network as the SCADA PC via an Ethernet switch or direct cable.
Ensure the SCADA PC has a static IP address on the same subnet (e.g., 192.168.1.101, subnet mask 255.255.255.0).
Verify Network Connectivity :
From the SCADA PC, ping the PLC’s IP address to confirm connectivity.
If the ping fails, check the IP settings, cables, and switch configuration.
Step 3: Configure the Adroit SCADA Modbus Ethernet Driver
Launch Adroit SCADA :
Open the Adroit Smart UI and access the Agent Server configuration.
Add a Modbus Ethernet Device :
In the Adroit configuration, navigate to the Device Configuration section.
Add a new device and select the Modbus Ethernet Driver (MOD_ETH).
Configure PLC Details (mod_eth.pdf, section 2.1.2):
PLC Station ID : Set to the PLC’s Modbus slave address (e.g., 1). Ensure it matches the address configured in the PLC.
PLC Type : Select a compatible PLC type from the dropdown (e.g., Quantum or Custom). For Delta PLCs, use “Custom” if the default types exceed the PLC’s buffer limits (see mod_eth.pdf, section 3.3). The Delta PLC supports:
Coils/Inputs: Up to 255 points (per the DVP protocol).
Registers: Up to 18 (16-bit) or 9 (32-bit) per transaction.
TCP/IP Address: Enter the PLC’s IP address (e.g., 192.168.1.100).
PLC Port Address: Set to 502 (default for Modbus TCP).
Leave “Create multiple connections” unchecked unless multiple logical devices share the same IP/port.
Step 4: Map PLC Data to Adroit Tags
Create Tags in Adroit:
In the Adroit Smart UI, create tags for the PLC data you want to monitor/control.
Use the appropriate addressing scheme based on the “Use IEC Standard Addressing” setting:
IEC Addressing :
Coils: %Q0–%Q65535 (maps to Y, M, T, etc.).
Inputs: %I0–%I65535 (maps to X, Y, M, etc.).
Holding Registers: %MW0–%MW65535 (maps to T, C, D).
Example: T20 = %MW614.
Modbus Addressing:
Coils: 000001–065535.
Inputs: 100001–165535.
Holding Registers: 400001–465535.
Example: T20 = 400615 (400001 + 614).
Data Types:
Boolean for coils/inputs (e.g., Y000).
Integer or Real for registers (e.g., T20).
String for specific applications (e.g., %MW0 S20 for a 20-char string).
Step 5: Test Communication
Start the Agent Server :
Ensure the Adroit Agent Server is running after configuration.
Monitor Tags:
In the Adroit Smart UI, view the tag values to confirm data is being read from the PLC.
Write to a tag (e.g., set Y000 to ON) and verify the PLC response (e.g., check the output state).
Reference information:
Adroit Modbus Ethernet driver manual. mod_eth.pdf (612.0 KB)
Delta DVP Communication protocol Manual - attached dvp_ communication protocol.doc (283.5 KB)
How to setup Modbus TCP Communication on the Adroit SCADA side: