Edwards and the Edwards logo are trademarks of Edwards Limited.
A735-01-860 Issue A
1Introduction
1.1Scope of this manual
This manual provides operational instructions for the Edwards nXDS pump serial communication protocol. Read this
manual before you attempt to operate your nXDS pump using serial communica tion protocol.
For safety and operating information for the nXDS range of pumps, please refer to the nXDS Scroll Pump Instruction
Manual (A735-01-880).
1.2Description
The nXDS pump can be operated in four control modes:
None in Control Mode - Inactive control mode
Manual Control Mode - Active control mode
Parallel Control Mode - Act ive control mode
Introduction
Serial Control Mode (including Serial Interlock) - Active control mode
The control mode is determined by the way the nXDS pump is started. All the control mo des, and transitions between
them, are defined in Figure 1.
Once started the nXDS pump can only be stopped by the mode in which it was started.
This instruction manual details the connection and operation of the nXDS pump in its serial control mode. The
parallel, manual and none in control modes are detailed in the nXDS Scroll Pump Instruction Manual (A735-01-880).
The nXDS pump can be connected directly to the RS485 or RS232 serial input on your control equipment or a PC, using
a suitable connector mating half (not supplied). Full serial control is realised by using the following two signa l lines:
serial enable and RS232 / RS485 control inputs.
Edwards and the Edwards logo are trademarks of Edwards Limited.
A735-01-860 Issue A
2Technical data
2.1Logic interface
nXDS pumps have a male 15-way D-type logic interface connector located on the user interface panel (Figure 2, Item
2). The logic interface connector can be plugged directly into your control equipment or a PC using a suitable
connector mating half (not supplied). Refer to Table 1 for the logic interface pins for the electrical connections and
Table 2 for the interface technical data.
Table 1 - Logic interface connection pins
Pin Number SignalUse
1Analogue Speed Enable-control Input Connect to Pin 2 (0 V) to enable analogue speed control via
Pin 9.
20 V Control Reference0 V reference for ALL control and status signals listed within
this table.
3START / STOP – Control InputConnect to Pin 2 (0 V) to START the nXDS pump system.
4STANDBY – Control Input /
RS232 Rx / RS485 A5Serial Enable – Control InputConnect to Pin 2 (0 V) to enable serial communications.
6RS232 / RS485 – Control InputDefault configuration is RS232 with Pin 6 unconnected.
7FAIL – Status Output /
RS232 Tx / RS485 B+
80 V Control Reference0 V reference for ALL control and status signals listed within
9Analogue Speed – Control Input0-10 V Analogue Input: 0 V = 0% Speed; +10 V = 100% Speed
10Chassis / ScreenScreen
11+10 V Analogue Reference – Control
Output
12Chassis / ScreenScreen
13Not ConnectedUnused control pin.
14REMOTE – Control InputConnect to Pin 2 (0 V) to enable remote operation via Parallel
15NORMAL – Status outputLogic LOW when the pump rotational speed is at normal
Connect to Pin 2 (0 V) to enable STANDBY speed when the
SERIAL ENABLE control input is inac tive.
Connect to Pin 2 (0 V) to enable RS485 serial
communications.
Logic HIGH when a fail / fault condition exists and the SERI AL
ENABLE control input is inactive.
this table.
+10 V analogue voltage reference output: 5 mA;
uni-polar output, diode protected.
Analogue speed input
Speed set accuracy± 5% full scale
NORMAL status output:
FAIL status output:
Analogue 10 V reference
Voltage accuracy± 2%
Output current≤ 5 mA for specified accuracy
*
Mating half of connector not supplied
*
Enable control voltage: low (closed)0 to 0.8 V d.c. (l
Disable control voltage: high (open)4 to 26.4 V d.c. (Internal pull up to 6.4 V nominal)
Enable control voltage: low (closed)0 to 0.8 V d.c. (l
Disable control voltage: high (open)4 to 26.4 V d.c. (Internal pull up to 3.2 V nominal)
Enable control voltage: low (closed)0 to 0.8 V d.c. (l
Disable control voltage: high (open)4 to 52.8 V d.c. (Internal pull up to 6.4 V nominal)
TypeOpen collector transistor plus pull up resistor.
< Normal speed (default 80%)OFF (4.7 k pull up + diode to 12 V d.c.)
≥ Normal speedON (< 0.8 V d.c. sinking 10 mA)
Maximum current rating10 mA
Maximum voltage rating28.8 V d.c.
TypeOpen collector transistor plus pull up resistor.
FailOFF (4.7 k pull up + diode to 12 V d.c.)
OKON (< 0.8 V d.c. sinking 10 mA)
Maximum current rating10 mA
Maximum voltage rating28.8 V d.c.
15-way D-type (male)
0 to 10 V d.c. directly proportional to the motor speed
e.g. 0 V = 0 Hz, 10 V = 30 Hz
+ 10 V d.c. analogue voltage reference
Unipolar output with diode protection