Edwards nEXT85 User Manual

Figure 6
Logic interface connecons - RS485 serial control
1. RS485 interface on control equipment
2. 24-48 V d.c. electrical supply
3. Fuse
4. nEXT pump logic interface
Serial enable
To send a serial message over the serial link, serial enable must rst be acvated.
Link the serial enable input signal (pin 5) to pin 2 of the customer logic interface mang half.
Edwards recommends incorporang this link into the serial communicaons cable so that the
serial enable is only acvated when the serial cable is connected. When the cable is removed,
serial enable will become inacve.
Serial enable acts as an interlock for start commands sent over the serial interface. If the pump
is running in serial control mode (having been sent a serial start command) and the serial
enable subsequently becomes inacve, the pump will trigger a fail condion and will
decelerate to rest. To clear this fail condion, re-acvate the serial enable and send a serial
stop command.
Connecon for mixed parallel and serial operaon
The pump can be controlled using parallel interface control inputs and at the same me
monitor various pump parameters using the serial interface or the USB service port using the
Edwards nST PC soware. Alternavely, the pump can be controlled using commands sent over
the serial interface while at the same me monitor the normal signal and analogue output over
the parallel interface.
Figure 7 on page 32 shows a schemac diagram of a system that demonstrates how to do
this. This connecon is a hybrid of the parallel and serial connecon which are described in
detail in Connect the parallel control and monitoring on page 27 and Connecon for serial
control and monitoring on page 28 respecvely. Many of the opons described in those
secons are available in mixed parallel and serial operaon but note that whilst serial enable is
acve to enable the serial link, the parallel standby and fail signals are not available. The mul-
drop connecon shown in Figure 7 on page 32 can also be used with mixed parallel and serial
operaon.
The pump cannot be controlled using both the parallel and serial interfaces simultaneously. For
example, if the pump is started by sending a start command over the serial interface, the pump
cannot then be stopped by using the start /stop switch on the parallel interface. The pump will
ignore the state of the start / stop switch on the parallel interface. To stop the pump, send a
serial stop command. Only when the serial stop command has been received by the pump can
any commands sent via the parallel interface be acted on.
B8G0-00-880A - Install the nEXT85
Page 31

Edwards nEXT85 Specifications

General

Brand	Edwards
Model	nEXT85
Category	Water Pump
Language	English