Edwards nEXT400 User Manual

6.4 Mixed parallel and serial operaon
In mix
ed parallel and serial operaon, the pump can receive commands from serial and
parallel interfaces. Refer to Figure: Serial and parallel control owchart to understand
how the commands controls the pump. The pump will power up with 'None in Control'.
From this state a parallel start signal or a serial start command can receive, which can
move the pump to parallel control mode or serial control mode. Serial start commands
can receive only if the serial enable line is acve.
The state of the serial enable line can be switched between acve and inacve while in
mixed parallel and serial operaon. The primary funcon of the serial enable line is to
enable the serial link. It has no direct eect on the control mode. The pump will receive
and respond to serial commands whenever the serial enable line is acve. The pump will
not receive or respond to serial commands when the serial enable line is inacve.
Availability of the parallel standby and fail signals depends on the state of the serial
enable line and the posion of the RS485/RS232 switch as given in Table: Serial enable
matrix.
Table 22 Serial enable matrix
RS485/
RS232
switch
Serial enable
Acve Inacve
RS232
Standby and fail lines are used for
RS232 data.
Standby and fail lines are used for par-
allel Standby control and fail indicaon.
Parallel standby control and fail indi-
caon are disabled.
Serial communicaons are disabled.
RS485
Standby and fail lines are used for
RS485 data.
Standby and fail lines are in (RS485)
high impedance state.*
Parallel standby control and fail indi-
caon are disabled.
Serial communicaons are disabled.
* The pump target speed will change between run speed and standby speed in response
to data driven onto the RS485 bus by other devices connected to the bus. Do not acvate
the parallel start line when the RS485/232 switch is in RS485 posion and serial enable
line is inacve. Do not deacvate the serial enable line when the pump is in operaon
aer a start from the parallel start line and the RS485/232 switch is in the RS485
posion.
In parallel control mode, the pump does not accept serial stop commands but will
accept all other serial commands. When serial enable is acve, the pump will operate at
standby speed if the serial standby command is given. When Serial Enable is inacve and
the RS485/RS232 switch is in RS232 posion, the pump will operate at standby speed
when the parallel standby line is acve.
In serial control mode, the state of the parallel Start line will be ignored but the serial
enable line gives an interlock funcon as shown in Figure: Serial and parallel control
owchart. This interlock funcon only operates with serial start commands and in serial
control mode only. In serial control mode, the pump cannot be commanded to standby
speed by the standby line, instead a serial standby command must be used.
04/2022 - ©Edwards Limited
Page 74B80000880_G
B80000880_G - Operaon

Edwards nEXT400 Specifications

General

Brand	Edwards
Model	nEXT400
Category	Water Pump
Language	English