Datasheet
Datasheet | Energy meter ALE3 with integrated Serial Modbus interface www.sbc-support.com |
5
Technical data Modbus
Protocol Modbus RTU according to IDA specication
Bus system RS-485 Serial line
Transmission rate (bps) 1200-2400-4800-9600-19'200-38'400-57'600-115'200.
The transmission Baud rate is automatically detected
Transmission mode Even parity: 8 data bits, 1 stop bit
Odd parity: 8 data bits, 1 stop bit
No parity: 8 data bits, 2 stop bits
Bus cable Twisted, shielded, 2 × 0.5 mm
2
, 1200 m max.
Response time typ. 5 character times
max. 60 ms
The interface works only if the Phase 1 is connected.
The communication is ready 30 s after the Power On.
Refresh Time for the data is 10 s. Therefore the delay between reads of the same data should be at least 10 s.
The use of Energy meters in Bus with intensive communication can increase the data refresh time.
247 devices can be connected to the Modbus. Over 128 devices, a repeater should be used.
The interface don’t have a terminal resistor, this should be provided external.
For the following transmission rate changes a restart of the counter is necessary:
1200 57'600, 1200 115'200 and 2400 115'20 0.
For a description of the used registers please look at the Register Page.
Data transmission
Only «Read Holding Registers [03]/ Write Multiple Registers [16]» instructions are recognized.
Up to 20 Registers can be read at a time.
The device supports broadcast messages.
In accordance with the Modbus protocol, a register R is numbered as R - 1 when transmitted.
The device has a voltage monitoring system. In case of voltage loss, registers are stored in EEPROM (transmission rate, etc.)
Exception Responses
ILLEGAL FUNCTION [01]: The function code is not supported.
ILLEGAL DATA ADDRESS [02]: The address of some requested registers is out of range
or more than 20 registers have been requested.
ILLEGAL DATA VALUE [03]: The value in the data eld is invalid for the referenced register.
Change the Modbus address direct on device
To modify the Modbus address, press 3 s on touch
In menu, increase address by 10, increase by 1
Once the address is selected wait for the root menu to come back