Edwards nEXT 55, Instruction Manual

Page: 49 / 116

Figure 20 Logic interface connections - parallel control
1. 24 - 48 V d.c. electrical supply 2. Fuse
3. Optional indicator - normal speed 4. Optional indicator - system OK
5. nEXT pump logic interface 6. Start switch
7. Optional standby switch 8. Optional voltmeter to monitor analogue
output
1. 24 - 48 V d.c. electrical supply 2. Fuse
3. Optional indicator - normal speed 4. Optional indicator - system OK
5. nEXT pump logic interface 6. Start switch
7. Optional standby switch 8. Optional voltmeter to monitor analogue
output
4.6 Connection for serial control and monitoring
In the serial interface, the pump is controlled through a number of serial commands or
the nST PC software. You can also check the operational status in the serial interface. In
the multi-drop mode, connection of more than one pump to a single serial port on the
control system is possible.
4.6.1 Connect the serial interface to the customer control equipment
The serial interface is available in RS485 or RS232 options. Use the slide switch (given
adjacent to the main power lead) to select the serial interface (refer to Figure: Motor
controller status information ). To adjust the slide switch, use a small tool to toggle the
slide switch. The default setting of the motor controller is RS232 serial interface. Replace
the round seal to make sure the pump stays IP rated.
CAUTION: PUMP GROUND CONNECTION
Risk of damage to equipment.
When connecting the pump to a PC, note that the 0 V pin on the RS232 connector
may be connected to earth through the PC. If this is the case, ensure that the 0 V rail
of the 48 V d.c. supply is not also connected to earth at some other point such as at
the power supply. If the 0 V rail of the 48 V d.c. supply will not be connected to earth
at the PC, an opto-isolated interface to the PC should be used.
The pump can connect to the RS485 or RS232 serial input on the control equipment or a
PC as shown in Figure: Logic interface connections - RS232 serial control and Figure:
Logic interface connections - RS485 serial control . In given configuration, the PC is the
serial link master and the pump is the slave. The distance over which the serial link will
work is dependent on the difference in voltage between the 0 V at the sending and
receiving end. If the 0 V reference at the receiving end is in 0.3 V of the 0 V control
reference pin on the pump control connector, then the serial link has to be capable to
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B8G000880_E - Installation