Mixed Parallel And Serial Operation; Note - Edwards nEXT730D Instruction Manual

The reply will be in the following format, where the first returned number refers to
motor rotational speed in revolutions per second (Hz):
Reply

Note:

The second return number is a 32-bit system status word (set of 8 hexadecimal
characters) which is useful for fault finding. Refer to

7.5 Mixed parallel and serial operation

In mixed parallel and serial operation the pump may receive commands from both serial
and parallel interfaces.
To understand how these commands control the pump, refer to
connection - mixed parallel and serial
Control'. From this state a parallel start signal or a serial start command may be received,
resulting in the pump moving to parallel control mode or serial control mode
respectively. Serial start commands will only be received if the serial enable line is active.
The state of the serial enable line may be switched between active and inactive whilst in
mixed parallel and serial operation. The primary function of the serial enable line is to
enable the serial link. It has no direct effect on the control mode. The pump will receive
and respond to serial commands whenever the serial enable line is active, and
conversely will not receive or respond to serial commands when the serial enable line is
inactive.
Availability of the parallel standby and fail signals depends on the state of the serial
enable line and the position of the RS485/CAN/RS232 switch as described in
enable matrix.
Table 21 Serial enable matrix
Switch
RS232
RS485
* 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. Activation of
the parallel start line not recommended with the RS485/CAN/RS232 switch in RS485
position and serial enable Inactive. Deactivation of the serial enable line is not
recommended with the pump running following a start from the parallel start line when
the RS485/CAN/RS232 switch is in the RS485 position.
In parallel control mode, the pump will not accept serial stop commands but will accept
all other serial commands. When serial enable is active, the pump will run at standby
B8J200880_D
300812671_002_C3
B8J200880_D - Operation
= v 8 5 2 sp d
Serial enable active
Standby and fail lines are used for
RS232 data.
Parallel standby control and fail indi-
cation are disabled.
Standby and fail lines are used for
RS485 data.
Parallel standby control and fail indi-
cation are disabled.
Page 83
d d d ; h h
Fault finding
operation. The pump will power up with 'None in
Serial enable inactive
Standby and fail lines are used for par-
allel Standby control and fail indica-
tion.
Serial communications are disabled.
Standby and fail lines are in (RS485)
high impedance state.
Serial communications are disabled.
h h h h h
on page 96.
Figure: Logic interface
Table: Serial
*
08/2021 - ©Edwards Limited
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