Solcon HRVS-DN series - HRVS-DN Communication (Modbus Protocol)

131 • HRVS-DN Communication (ModBus Protocol)
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16. HRVS-DN COMMUNICATION (MODBUS PROTOCOL)
16.1 Introduction
This document summarizes the Modbus serial link protocol to / from the Digital Soft Starter (HRVS-DN). The
HRVS-DN can be equipped with many other serial link protocols.
Features:
* RS485 Hardware.
* Asynchronous serial link.
* Half duplex.
* Format: Modbus RTU Mode (Remote Terminal Unit Mode).
- Binary,
- Each character contains 11 bits:
- 1 start bit
- 8 data bits, least significant bit sent first.
- 1 Parity bit. Even / Odd / No can be selected.
- 1 Stop bit if Parity is used, 2 stop bits if Parity is not used.
- Cyclical Redundancy Check (CRC), 16 bits.
* Baud Rates: 1200 / 2400 / 4800 / 9600 bits per second.
* Response time of the HRVS-DN:
- Normally, 4ms <= time response <= 40mS .
- For a long response, time response <= 200mS.
* It is not recommended to transmit to the HRVS-DN, at a rate higher than once per second because this
can slow down HRVS-DN response times.
* After storing parameter settings, there is a 1 sec. time period during which transmission to the same
HRVS-DN is forbidden.
* Broadcast commands: not supported.
Notes:
* You must connect earth to the earth screw before connecting serial link wires. Ignoring this
instruction may result in permanent damage to the Serial Link Hardware, and can be dangerous.
* It is recommended that you connect 120 OHM resistors to both ends of the serial link.
* When the serial link is connected to Solcon's Serial Link Adapter you are not allowed to connect the 120
OHM resistors.
* Turn off (and on again) power to the controller after changing Baud_Rate, Parity_Check or Serial_Link_No
(Slave Address). These parameters can only be modified manually and not through the Serial Link.