TTK FG-SYS - Page 36

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- Serial link RS232 or RS422/485.
The serial link is asynchronous.
The serial link and Modbus protocol settings are as follows:
Serial port setup: 9600 B, 8 data bits, 1 stop bit, no parity;
Communication protocol: JBUS or MODBUS, function 3 or 4;
Slave number: 1 - 247 (configurable);
Maximum number of records read by request: 100
Answer Format:
num. slave function nb of Registers Register 1 Register 2 … Register n CRC 16
 1, 2… 99  3 or 4  up to 100  XXXXh  XX XXh  …  XXXXh  XXXXh 
For the proper functioning of the RS485, it is necessary to connect Rx+ with Tx+ and Rx- with Tx-. In
addition, it is essential to complete the line of communication via a two-wire resistance of 120 Ohms.
The connection of the screen is provided on the supervisor side.
The polarisation of communication lines from RS422/485 must be ensured by the supervisor.
It is recommended to provide a break of at least 500 mms between JBUS polls.
Caution!
The simultaneous use of RS232 and RS422/485 interfaces causes the serial interface of the FG-SYS Digital Unit
to power down.