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Installation
B800-00-880 Issue D
Figure 12 - Controller status information
When connecting the nEXT pump to a PC, remember that the 0 V pin on the RS232 connector may well be
connected to earth through the PC. If this is the case, ensure that the 0 V rail of the 24 - 48 V supply is not also
connected to earth at some other point such as at the power supply. If the 0 V rail of the 24 - 48 V supply will
not be connected to earth at the PC, an opto-isolated interface to the PC should be used.
The nEXT pump can connect directly to the RS485 or RS232 serial input on the control equipment or a PC as shown
in Figure 13 and 14. In this configuration the PC is the serial link master and the nEXT pump is the slave. The distance
over which the serial link will work is dependent on any difference in voltage between the 0 V at the sending and
receiving end. If the 0 V reference at the receiving end is within 0.3 V of the 0 V Control Reference pin on the nEXT
pump control connector then the serial link should be capable of operating at distances up to 6 m. An interface circuit
external to the nEXT pump may be required for longer distances.
The software in the nEXT pump is capable of operating with several pumps connected to a single serial link master.
This is referred to as multi-drop mode. The RS485 option is recommended for multi-drop mode. With the RS232 option
selected, some additional hardware will be required to link several nEXT pump units to a single serial link master. A
concept drawing of one possible arrangement is shown in Figure 15. Conversely when the RS485 option is selected,
connecting several nEXT pumps to a single master becomes a simple wiring exercise as shown in Figure 16.
1. Standby speed increase button
2. RS485/RS232 switch
3. Controller connector socket
4. Standby speed reduce button
5. Alarm LED
6. Status LED
7. Normal LED
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