F-901B Reference Manual
Page
7
of
15
MODBUS
The F901B supports the standard Modbus protocol in both RTU and TCP/IP mode:
•
TCP/IP: the factory default mode. Upon powering up, the F901B initializes the Modbus TCP/IP protocol via
the default static IP address 192.168.1.50 port 502 (This address is configurable via
).
•
RTU: The F901B sensor can be configurated to operating in RTU (RS485) mode by setting the
register and swapping the internal cables inside the sensor. See below for RTU
specifications.
RTU RS485 Configuration
Pin Description
Pin
Name
Type
Description
1
3.3V
Reference potential
3.3V Reference Voltage
2
GND
Reference potential
Local device ground
3
UART_TX
Digital Output
Firmware update interface
4
B (D-)
Bus In/Out
Driver output and receiver input
5
A (D+)
Bus In/Out
Driver output and receiver input
6
UART_RX
Digital Input
Firmware update interface
7
BOOT
Digital Input
Firmware update interface
8
RESET
Digital Input
Microcontroller reset input (Active-Low) Firmware
update interface
Note: use pin 4,5 (B/A) and GND for Modbus RS485 communication. Pin 3,6,7,8 are reserved for firmware updating
and are
3.3V
tolerant.
Sampling cycle
Cleaning cycle
Trigger interval
idle time
8 7 6 5 4 3 2 1
RJ-45
Plug
RJ-45
Socket
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
Figure 3 Trigger measurement timing
