Edwards nEXT85 User Manual

Mixed parallel and serial operaon
In mixed parallel and serial operaon the pump may receive commands from both serial and
parallel interfaces.
To understand how these commands control the pump, refer to Figure 7 on page 32. The pump
will power up with ‘None in Control’. From this state a parallel start signal or a serial start
command may be received,
resulng in the pump moving to parallel control mode or serial
control mode respecvely. Serial start commands will only be received if the serial enable line
is acve.
The state of the serial enable line may be switched between acve and inacve whilst 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, and conversely 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 described in Table 9 on page 52.
Table 9
Serial enable matrix
Switch Serial enable acve Serial enable inacve
RS232
Standby and fail lines are used for
RS232 data.
Standby and fail lines are used for
parallel Standby control and fail
indicaon.
Parallel standby control and fail
indica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
indicaon are disabled.
Serial communicaons are disabled.
*
Pump target speed will switch between run speed and standby speed in response to any data driven onto the
RS485 bus by other devices connected to the bus. Acvaon of the parallel start line not recommended with the
RS485/232 switch in RS485 posion and serial enable Inacve. Deacvaon of the serial enable line is not
recommended with the pump running following a start from the parallel start line when the RS485/232 switch is in
the RS485
posion.
In parallel control mode, the pump will not accept serial stop commands but will accept all
other serial commands. When serial enable is acve, the pump will run at standby speed if it
has been commanded to do so by a serial standby command. When Serial enable is inacve
and the RS485/RS232 switch is in RS232 posion, the pump will run 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 provides an interlock funcon as shown in Figure 9 on page 53. This interlock funcon
only operates with serial start commands and therefore only in serial control mode. In serial
control mode, the pump cannot be commanded to standby speed by the standby line, instead
a serial standby command must be used.
The parallel normal and analogue output signals provide valid pump status informaon at all
mes under mixed parallel and serial operaon. The analogue output voltages are described in
Table 43 on page 91.
B8G0-00-880A -
Operaon of the nEXT85
Page 52

Edwards nEXT85 Specifications

General

Brand	Edwards
Model	nEXT85
Category	Water Pump
Language	English