Supported Devices

Device Type	Modbus TCP (Ethernet)	RS485
PLA33	✅	✅
PLA33RX

Figure 1: Front panel of the PLA33 showing buttons like SET, cursor keys, and ESC.

Figure 2: Front panel of the PLA33RX showing buttons like ESC, cursor keys, and status LEDs for recording and relay outputs.

Wiring

RS485

For RS485 wiring, follow the guidelines for RS485 wiring.

RS485 Wiring

• For correct RS485 wiring: Follow the guidelines for RS485 wiring.
• If the wiring shown in the table below is incorrect, please let us know.
• There is no general consensus in the industry about the usage of A and B for the RS485 polarity, so it may be counterintuitive and opposite of what you might expect for some devices.

Device	SmartgridOne Controller model OM1	SmartgridOne Controller model IG8	RS485-USB converter	RS485-Ethernet converter
A	RS485 A	RS485_POS	RS485 A	TX+
B	RS485 B	RS485_NEG	RS485 B	TX-
GND	RS GND	GND	Not available	G

NOTE: RS485 Device Addresses

• You MUST give each device on the RS485 bus a unique address. Check the manual of the device on how to do this.
• Use lower addresses first (1, 2, ...) because the SmartgridOne Controller will find them faster!
• For each device, it is generally recommended to stick with the factory default baud rate, parity, and stop bits. The SmartgridOne Controller will scan on those first.

Ethernet

For Ethernet wiring, follow the guidelines for Ethernet wiring.

---

Configuration

RS485 Configuration

To configure RS485 communication on BMR energy meters, follow these steps:

1. Set the Modbus Address:

   • Access the settings menu by pressing the SET button for 5 seconds.
   • Navigate to the communication menu (P_2) using the cursor keys.
   • Set the Id (unique Modbus address) between 1 and 247.

2. Set the Baud Rate:

   • In the communication menu (P_2), configure the bd (baud rate) to match your system. Supported baud rates include 9.6 / 19.2 / 38.4 / 57.6 / 115 kBd.

3. Parity and Stop Bits:

   • Configure PAr (parity) as None, Odd, or Even.
   • Set the St (stop bits) to 1 or 2 as needed.

4. RS485 Termination:

   • If the meter is the last device on the RS485 bus, add a 120 Ω termination resistor.

NOTE: RS485 Device Addresses

• You MUST give each device on the RS485 bus a unique address. Check the manual of the device on how to do this.
• Use lower addresses first (1, 2, ...) because the SmartgridOne Controller will find them faster!
• For each device, it is generally recommended to stick with the factory default baud rate, parity, and stop bits. The SmartgridOne Controller will scan on those first.

---

Ethernet Configuration (PLA33RX Only)

For devices with Ethernet capability:

1. Ensure the Ethernet cable is properly connected.
2. Use the Power Monitoring Software (PMS) to configure the IP address, subnet mask, and gateway.
3. Verify that the Modbus TCP port is set to 502.