Edwards nEXT 55, Instruction Manual

Page: 48 / 116

CAUTION: BACK EMF SUPPRESSION DIODE
Risk of damage to equipment. If the normal and fail lines are used to drive the coils of
the d.c. relays, install a back EMF suppression diode in parallel with each relay coil to
protect the pump.
Connect the customer control equipment to the control input pins of the customer logic
interface mating half. Refer to Table: Logic interface connector pins to identify the
connector pins of the logic interface.
The control inputs are:
▪ Start
▪ Standby speed
To activate one of the control inputs, connect the control input pin to the 0 V control
reference. To start the pump, connect the pin 3 (Start / Stop) to the pin 2 (0 V reference).
To stop the pump, remove the connection between the pin 3 and pin 2. To put the pump
in standby, connect the pin 4 (Standby) and pin 3 (Start / Stop) to pin 2 (0 V reference).
Note:
Serial enable is also a control input, it is not necessary in a system that operates under
parallel control. Make sure that there is no connection to the serial enable (pin 5).
Note:
To use the standby or fail parallel interface signals, make sure that the RS485 / RS232
slide switch is in the RS232 (default) position. Refer to Connect the serial interface to the
customer control equipment on page 49.
1. To monitor an analogue output, connect the customer control equipment to the
pump analogue output (pin 9) and to the pin 2 of the customer logic interface
mating half.
When the pump is shipped, the analogue output is configured to monitor the
rotational speed of the pump. To monitor other parameters, configure the pump
again using the commands over the serial interface. Refer to Connection for serial
control and monitoring on page 49 for more information.
2. To monitor the normal status output, connect the customer control equipment to
the normal status output (pin 15) and to the pin 2 of the customer logic interface
mating half.
You can use the output to control other devices in the pumping system. The output
can operate a low power relay of up to 24 V d.c. coil rating (up to 20 mA).
3. To monitor the fail status output, connect the customer control equipment to the
fail output (pin 7) and to the pin 2 of the customer logic interface mating half.
You can use the output to control other devices in the pumping system. The output
can operate a low power relay of up to 24 V d.c. coil rating (up to 20 mA).
07/2021 - ©Edwards Limited Page 48 B8G000880_E
B8G000880_E - Installation