3.4.2.5 MODBUS
Only available in variant NMT(D) MAX C.
Data protocol
Modbus connector
Modbus connection
type
Modbus
wire
configuration
Communication
transceiver
Maximum
cable
length
Slave address
Line termination
Supported
transmission speeds
Start bit
Data bits
Stop bits
Parity bit
Modbus
visual
diagnostics
Maximum number of
Modbus devices
Maximum
Modbus
packet size
Isolation
POWER SUPPLY
Power supply output is meant for automation elements. Avalabile on
Maximum current
100 mA
Output voltage
24 V ± 20 %
Output ripple
<1 V
Misconnection or overload could cause pump shutdown or even permanent damage.
Modbus specification
Modbus RTU
Screwless terminals
RS-485
Two-wire + common
Integrated,
1/8
of
standard load
1200 m
1-247
Not present
1200, 2400, 4800, 9600,
19200, 38400 baud
1
8
1 or 2
Even/odd/none
LED2
247
256 bytes
Common ground (COM)
with SET1, SET2 and
SET3.
Electrical properties
2+1 pins. See NMTC module manual.
Conductors:
A,
B
See section See NMTC module manual.
Connect either via passive taps or daisy chain.
See section See NMTC module manual.
Default is 245, settable over Modbus. See NMTC
module manual.
Line termination is not integrated. For low
speed/short distance, termination can be omitted.
Otherwise, terminate the line externally on both
ends.
Settable over Modbus register [default=19200].
Fixed.
Fixed.
1 stop bit minimum, up to 2 when parity not
enabled [default=1]
[default=Even]
Flashing yellow when data reception detected.
Combined (OR) with Ethernet ACT function.
Limited by possible Modbus addresses to 247. 1/8
nominal load enables 256 devices.
Including address (1) and CRC (2) bytes.
Modbus shares common ground with other
signals.
NMT(D) MAX C > 850 W.
27
and
COM
(Common).