Saia-Burgess Controls AG
Bahnhofstrasse 18 I CH-3280 Murten I Schweiz
T +41 26 580 30 00 I F +41 26 580 34 99
www.sbc-support.com
Technical data Modbus
Bus system
Modbus, RTU according to IDA specification
Transmission rate
4800-9600-19 200-38 400-57 600-115 200.
The transmission Baud rate is automatically detected
Transmission mode
No parity: 8 data bits, 1 stop bit
Bus length (max.)
1200 m (without repeater)
Response time:
Write: up to 60 ms
Read: up to 60 ms
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The communication is ready 30 s after the power on
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The use of energy meter in bus with intensive communication could reduce the performance of the bus
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Refresh time for the data is 5 s. For this reason one energy meter should be not polled faster as 5 s
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247 devices could be connected to the Modbus. With more than 128 devices, a repeater should be used
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The interface don’t have a terminal resistor, this must be provided external
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For a description of the used registers please look at the register page
Data transmission
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Only «Read Holding Registers [03]/ Write Multiple Registers [16]» instructions are recognized.
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Up to 20 Registers can be read at a time.
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The device supports broadcast messages.
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In accordance with the Modbus protocol, a register R is numbered as R - 1 when transmitted.
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The device has a voltage monitoring system. In case of voltage loss, registers are stored in EEPROM (transmission rate, etc.)
Exception Responses
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ILLEGAL FUNCTION [01]: The function code is not supported.
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ILLEGAL DATA ADDRESS [02]: The address of some requested registers is out of range
or more than 20 registers have been requested.
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ILLEGAL DATA VALUE [03]: The value in the data field is invalid for the referenced register.
Changing the Modbus address direct on device
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In the menu, go for «U»
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Push long ( ≥ 3 sec)
➞
«Adr»
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Push short
➞
a1, push long
➞
a10
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Once the desired address is selected wait, to validate, till the root menu to come back
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