Mixed Parallel And Serial Operation; Table 9 Serial Enable Matrix - Edwards nEXT85 Instruction Manual

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
will power up with 'None in 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/RS232 switch as described in

Table 9 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
RS485/232 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 RS485/232 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 speed if it
has been commanded to do so by a serial standby command. When Serial enable is inactive
and the RS485/RS232 switch is in RS232 position, the pump will run at standby speed when the
parallel standby line is active.
In serial control mode, the state of the parallel Start line will be ignored but the serial enable
line provides an interlock function as shown in
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 information at all
times under mixed parallel and serial operation. The analogue output voltages are described in
Table 43 on page 91.
B8G0-00-880A - Operation of the nEXT85
Serial enable active
Standby and fail lines are used for
RS232 data.
Parallel standby control and fail
indication are disabled.
Standby and fail lines are used for
RS485 data.
Parallel standby control and fail
indication are disabled.
Page 52
Figure 7
Table 9 on page 52.
Serial enable inactive
Standby and fail lines are used for
parallel Standby control and fail
indication.
Serial communications are disabled.
Standby and fail lines are in (RS485)
high impedance state.
Serial communications are disabled.
Figure 9 on page 53. This interlock function
on page 32. The pump
*