16
1. INTRODUCTION
This document summarizes the serial link protocol to / from the DIGITAL SOFT STARTER (RVS-AXO).
Features:
*
RS485 Hardware.
*
Asynchronous serial link.
*
Half duplex.
*
Format:
Modbus RTU Mode
(Remote Terminal Unit Mode).
- Binary,
- Each character includes 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.
-
C
yclical
R
edundancy
C
heck (CRC), 16 bits.
*
Baud Rates: 1200/2400/4800 / 9600/19200 bits per second..
*
Response time of the RVS-AXO:
- Normally, 4ms <= time response <= 40mS.
- For a long response, time response <= 200mS.
*
It is not recommended to transmit to the RVS-AXO too often, at a faster rate than once per second,
as it can slow down RVS-AXO time delays.
*
After storing setting parameters, it is forbidden to transmit again to the same RVS-AXO in less
than 1 Sec.
*
Broadcast commands: not supported.
Notes:
* It is recommended to connect 120 OHM resistors on both ends of the serial link.
* Turn off (and on again) control power after changing Baud Rate, Parity Check or Serial Link No (Slave
Address).
*
It is a must to connect earth to the RVS-AXO earth terminal before connecting serial link wires.
Ignoring this instruction may result in permanent damage to the Serial Link Hardware.
*
Being in Start / Soft Stop state RVS-AXO is busy controlling its SCRs and
will not respond
to
requests.
