MICRONOR AG
MR340-1 DIN Rail Module Controller
Page 30 of 74
4.
Modbus Serial Communications
4.1
Modbus Serial Interface
The main purpose of the Modbus-compatible serial interface is to query the controller for
status, position and speed while in operation. The serial interface is also used to configure the
controller unit as well as system troubleshooting.
MICRONOR supplies the ZAPPY®302 software to access these functions via the USB or RS232
serial interface of your PC (Personal Computer) computer.
Serial Interface Specification (default)
•
Serial with logic levels full duplex.
•
Baudrate programmable: 57,600 baud
•
1 Start Bit
•
8 Data Bits
•
1 Stop Bit
•
no parity
The protocol is Modbus compatible and thus the protocol includes a node address. That is so
that the PCB could be integrated into larger systems using a number of Modbus slaves.
Factory Standard ModBus Address is set to 235 (Hexadecimal 0xEB).
Note: The MR340-1 Controller requires a RS485/422-to-RS232 converter for interfacing to the
RS232 COM Port of a computer.
Note: The MR340-1 Controller uses the 235 address as the common call address. It will
always respond to address 235.
Pull-Up/Pull-Down Resistors
Since the bus lines will go idle and into an undefined state when inactive, it is important that
the lines are pulled-up and pulled-down respectively when inactive.
The pull-up / pull-down resistor are typically at the master. Consult following Modbus circuit
definitions.