052
www.ruggedaq.com
DATALOGGER
NI400
NI400
053
www.ruggedaq.com
DATALOGGER
NI400
NI400
MODBUS SENSORS
What’s Modbus?
Modbus is a serial communication protocol, made by Modicon in 1979 to link their PLC.
It has become a de facto standard in communication protocol, and it’s now a commonly
available means of connecting industrial electronic devices.
Advantages in industrial sectors are:
• developed with industrial applications in mind
• openly published and royality-free
• easy to deploy and mantain
• moves raw bits or words without placing many restriction on vendors
Modbus enables communication among many devices connected to the same network, for
example a system that measures temperature and humidity and communicates the results
to a computer. Modbus is often used to connect a supervisory computer with a remote ter-
minal unit (RTU) in supervisory control and data acquisition (SCADA) systems. Many of the
data types are named from its use in driving relays: a single-bit physical output is called a
coil, a single-bit physical input is called a discrete input or a contact.
OBJECT TYPE
ACCESS
SIZE
Coil
Read-Write
1-bit
Discrete Input/Contact
Read-Only
1-bit
Input Register
Read-Only
16-bits
Holding Register
Read-Write
16-bits
Digital Sensor Configuration
For digital sensors, NI400 offers an in-depth configuration. After choosing Baudrate and
Maximum RS485 Address (
Fig.1
), the User can “Save Changes” and start the configuration
of the sensors.
By clicking “Edit” (
Fig.2
) on the sensor row to configure, the system shows typical sensor
(IPI, H-LEVEL, TILTMETER) and a SmartModbus element (
Fig.3
).
SmartModbus is selected if the User has a generic modbus sensor.
Figure 50
Figure 51
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