Edwards nXDS6i User manual

A735-01-860
Issue A Original
Instruction Manual
nXDS Serial Comms Interface
Description Item Number
nXDS6i A735-01-983
nXDS10i A736-01-983
nXDS15i A737-01-983
nXDS20i A738-01-983
nXDS6iC A735-02-983
nXDS10iC A736-02-983
nXDS15iC A737-02-983
nXDS20iC A738-02-983
nXDS6iR A735-03-983
nXDS10iR A736-03-983
nXDS15iR A737-03-983
nXDS20iR A738-03-983

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Contents
A735-01-860 Issue A
Contents
Section Page
1 Introduction ........................................................................................1
1.1 Scope of this manual.................................................................................................... 1
1.2 Description................................................................................................................ 1
2 Technical data .....................................................................................3
2.1 Logic interface........................................................................................................... 3
3 Connection for serial control and monitoring.................................................5
3.1 Serial connection ........................................................................................................ 5
3.2 Serial enable ............................................................................................................. 6
3.3 Serial protocol ........................................................................................................... 6
3.4 Message structure ....................................................................................................... 7
3.5 Command set............................................................................................................. 7
3.6 Operating the nXDS pump............................................................................................. 12
3.6.1 Start the pump.......................................................................................................... 12
3.6.2 Standby speed........................................................................................................... 12
3.6.3 Stop the pump .......................................................................................................... 12
3.7 Multi-drop operation................................................................................................... 13
3.7.1 Assigning a multi-drop address ....................................................................................... 14
3.8 Mixed parallel and serial operation.................................................................................. 15
3.9 Decoding status words................................................................................................. 16
3.9.1 Decoding system status word......................................................................................... 16
3.9.2 Decoding service status word......................................................................................... 19
For return of equipment, complete the HS Forms at the end of this manual.
gea/0207/06/12

A735-01-860 Issue A
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Contents
Illustrations
Figure Page
1 Start / Stop Control Diagram ........................................................................................... 1
2 nXDS scroll pump ......................................................................................................... 2
3 Logic interface connections - RS232 serial control.................................................................. 5
4 Logic interface connections - RS485 serial control.................................................................. 6
5 RS485 multi-drop connections.........................................................................................13
6 Logic interface connection - mixed parallel and serial operation ...............................................15
Tables
Table Page
1 Logic interface connection pins........................................................................................ 3
2 Logic interface technical data.......................................................................................... 4
3 Summary of the commands that can be sent to the nXDS pump.................................................. 8
4 Command abbreviations................................................................................................11
5 Error codes ...............................................................................................................11
6 Hexadecimal conversion table.........................................................................................16
7 System status register 1 flags..........................................................................................17
8 System status register 2 flags..........................................................................................17
9 Warning register 2 flags ................................................................................................18
10 Fault register flags ......................................................................................................19
11 Service flags..............................................................................................................20
Associated publications
Publication title Publication number
Vacuum Pump and Vacuum System Safety P400-40-100
nXDS Scroll Pump Instruction Manual A735-01-880

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Introduction
A735-01-860 Issue A
1Introduction
1.1 Scope 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 communication protocol.
For safety and operating information for the nXDS range of pumps, please refer to the nXDS Scroll Pump Instruction
Manual (A735-01-880).
1.2 Description
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 - Active control mode
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 modes, 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.
Figure 1 - Start / Stop Control Diagram

A735-01-860 Issue A
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Introduction
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 signal lines:
serial enable and RS232 / RS485 control inputs.
Figure 2 - nXDS scroll pump
1. User interface panel
2. 15-way logic interface connection

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Technical data
A735-01-860 Issue A
2Technicaldata
2.1 Logic 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 Signal Use
1 Analogue Speed Enable-control Input Connect to Pin 2 (0 V) to enable analogue speed control via
Pin 9.
2 0 V Control Reference 0 V reference for ALL control and status signals listed within
this table.
3 START / STOP – Control Input Connect to Pin 2 (0 V) to START the nXDS pump system.
4STANDBY–ControlInput/
RS232 Rx / RS485 A- Connect to Pin 2 (0 V) to enable STANDBY speed when the SERIAL ENABLE control input is inactive.
5 Serial Enable – Control Input Connect to Pin 2 (0 V) to enable serial communications.
6 RS232 / RS485 – Control Input Default configuration is RS232 with Pin 6 unconnected.
Connect to Pin 2 (0 V) to enable RS485 serial
communications.
7 FAIL – Status Output /
RS232 Tx / RS485 B+ Logic HIGH when a fail / fault condition exists and the SERIAL ENABLE control input is inactive.
8 0 V Control Reference 0 V reference for ALL control and status signals listed within
this table.
9 Analogue Speed – Control Input 0-10 V Analogue Input: 0 V = 0% Speed; +10 V = 100% Speed
10 Chassis / Screen Screen
11 +10 V Analogue Reference – Control
Output +10 V analogue voltage reference output: 5 mA; uni-polar output, diode protected.
12 Chassis / Screen Screen
13 Not Connected Unused control pin.
14 REMOTE – Control Input Connect to Pin 2 (0 V) to enable remote operation via Parallel
control mode.
15 NORMAL – Status output Logic LOW when the pump rotational speed is at normal
speed or above.

A735-01-860 Issue A
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Technical data
Table 2 - Logic interface technical data
Logic interface description
Connector*
*Mating half of connector not supplied
15-way D-type (male)
Start, serial enable and remote enable:
Enable control voltage: low (closed) 0 to 0.8 V d.c. (lOUT = 0.55 mA nominal)
Disable control voltage: high (open) 4 to 26.4 V d.c. (Internal pull up to 6.4 V nominal)
Standby control input:
Enable control voltage: low (closed) 0 to 0.8 V d.c. (lOUT = 0.3 mA nominal)
Disable control voltage: high (open) 4 to 26.4 V d.c. (Internal pull up to 3.2 V nominal)
Analogue and RS485 enable control inputs:
Enable control voltage: low (closed) 0 to 0.8 V d.c. (lOUT = 0.55 mA nominal)
Disable control voltage: high (open) 4 to 52.8 V d.c. (Internal pull up to 6.4 V nominal)
Analogue speed input 0 to 10 V d.c. directly proportional to the motor speed
e.g. 0 V = 0 Hz, 10 V = 30 Hz
Speed set accuracy ± 5% full scale
NORMAL status output:
Type Open collector transistor plus pull up resistor.
< Normal speed (default 80%) OFF (4.7 k pull up + diode to 12 V d.c.)
≥Normal speed ON (< 0.8 V d.c. sinking 10 mA)
Maximum current rating 10 mA
Maximum voltage rating 28.8 V d.c.
FAIL status output:
Type Open collector transistor plus pull up resistor.
Fail OFF (4.7 k pull up + diode to 12 V d.c.)
OK ON (< 0.8 V d.c. sinking 10 mA)
Maximum current rating 10 mA
Maximum voltage rating 28.8 V d.c.
Analogue 10 V reference + 10 V d.c. analogue voltage reference
Unipolar output with diode protection
Voltage accuracy ± 2%
Output current ≤5 mA for specified accuracy

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Connection for serial control and monitoring
A735-01-860 Issue A
3 Connection for serial control and
monitoring
The serial interface allows you to control the nXDS pump and to interrogate its operational status using a number of
serial commands. There is also a multi-drop mode that allows you to connect more than one nXDS pump to a single
serial port on your control system.
3.1 Serial connection
The nXDS pump can connect directly to the RS485 or RS232 serial input on your control equipment or a PC as shown
in Figure 3 and 4. In this configuration the PC is the serial link master and the nXDS pump is the slave. The RS232
serial link is capable of operating reliably at distances up to 6m. The RS485 serial link is recommended to maintain
reliable serial communications at distances greater than 6m. Alternatively an interface circuit, external to the nXDS
pump, may be required to communicate using the RS232 serial link over longer distances.
The software in the nXDS pump is capable of operating with several pumps connected to a single serial link master.
This is referred to as multi-drop mode (refer to Section 3.7). The RS485 option is recommended for multi-drop mode.
To enable the RS485 option, link the RS485 input signal to the 0 V Control Reference (pin 6 to pin 2) of your logic
interface mating half.
Figure 3 - Logic interface connections - RS232 serial control
1. RS232 interface on control equipment or PC
2. nXDS pump logic interface

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Connection for serial control and monitoring
Figure 4 - Logic interface connections - RS485 serial control
3.2 Serial enable
To send a serial messageyou must first activateserial enable. This is achieved by linking the serial enable input signal
(pin 5) to pin 2 of your logic interface mating half. We recommend that you incorporate this link into your serial
communications cable so that the serial enable is only activated when the serial cable is connected. When you
subsequently remove the cable, serial enable will become inactive.
Serial enable acts as an interlock for start commands sent over the serial interface. If the nXDS pump is running in
serial control mode (having been sent a serial start command) and the serial enable subsequently becomes inactive,
the nXDS pump will trigger a fail condition and will decelerate to rest. To clear this fail condition, you must re-
activate the serial enable and send a serial stop command.
3.3 Serial protocol
The serial interface link is set to 9600 Baud, 8 bits, 1 stop, no parity with no handshaking. The commands are made
up from printable ASCII characters. The maximum message size you can send is 80 characters, including start and end
characters.
All alphabetical characters must be sent in upper case format. Response may contain lower case characters.
Every complete command message you send will receive a response - either a status code or a data return. The nXDS
pump can only deal with one message at a time. It will only accept a new message once the response to the previous
message has been returned.
If the nXDS pump receives characters that are not framed inside start and stop characters, it will ignore them.
Messages with the stop character missing will be discarded with no response when a new start character is received.
If the nXDS pump receives an unrecognisable message between the start and stop characters, it will return an
appropriate error message.
1. RS485 interface on control equipment or PC
2. nXDS pump logic interface

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Connection for serial control and monitoring
A735-01-860 Issue A
3.4 Message structure
The message structure and command set are the same for RS485 and RS232 options. To communicate a message to
the nXDS pump you must send the characters in a specific order. If the message does not conform to the correct
structure it will be ignored and no reply will be sent.
There are two basic types of message sent to the nXDS pump:
A command sending information to the nXDS pump; this is prefixed with a '!' character
A query requesting information from the nXDS pump; this is prefixed with a '?' character
Data is stored and accessed via two memory types within the nXDS Pump:
Non-volatile memory - this provides access to persistent data which is restored after power-cycling; the
prefix 'S' indicates persistent data.
Volatile memory - this provides access to non-persistent data which is NOT restored after power-cycling; the
prefixes 'C' and 'V' indicate non-persistent data.
The correct structure to use is as follows:
a valid start character, either a '!' character for a store operation or a '?' character for a query operation,
followed by
a command, which will be an upper case alphabetical character, followed by
an object number, comprising three decimal digits, followed by
for some commands only, a data field, comprising a sequence of characters separated from the object
number by a space, followed by
a terminating carriage return, as the stop character
An extended message protocol is used in multi-drop mode, refer to Section 3.7.
3.5 Command set
Table 3 shows a summary of the full set of commands available for controlling and monitoring the nXDS pump.
Table 4 shows the abbreviations that are used to define commands in the following sections and Table 5 shows the
error codes that might be returned.

A735-01-860 Issue A
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Connection for serial control and monitoring
Table 3 - Summary of the commands that can be sent to the nXDS pump
Object name Command Parameter
range Factory setting Data type Units Comments
Identification ?S0 - - - -
Acts as wildcard object num-
ber to identify
instrument.
Reply identical to ?S801
Node ?S800
!S800 0..98 0 Decimal Slave
Address Multi-drop address (RS485) 0 = disable multi-drop mode;
Pump type ?S801
[1..8] - String ASCII
Characters Pump type (nXDS)
[1..11] - String ASCII
Characters
Motor-Control Software
Version number (Dxxxxxxxx Y)
(where Dxxxxxxxx is the
drawing number and Y is the
revision)
1..255 - String Hz Design frequency (= Nominal mechanical frequency of the
pump)
Pump control
!C802 0-Decimal -Stop the pump
1 - Decimal Start the pump
?V802
0..255 - Decimal Hz Reported motor frequency
64-bits
encoded as
four
16-bit words:
<0000..FFFF>;
<0000..FFFF>;
<0000..FFFF>;
<0000..FFFF>
-Hexadeci-
mal -
System status:
System status register 1;
System status register 2;
Warning register and Fault
register*
Speed control !C803 0-Decimal -Use full speed
1 - Decimal Use standby speed
Normal speed
threshold ?S804 !S804 50..100 80 Decimal %
Normal speed status output
trigger level:
Percentage (%) of selected
speed
Standby speed
setting
?S805
!S805 66..100 70 Decimal %
Standby speed of pump:
Percentage (%) of full
mechanical speed (see 801)
!S stores standby speed to
non-volatile memory
(use !C805 for real-time
speed control, faster
execution and extended non-
volatile memory life)
!C805 !C retains value in volatile
memory only
Auto-run ?S806
!S806 0 10 Decimal -
Run the nXDS Pump-System
from power-on:
Enable = 1
Disable = 0

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Connection for serial control and monitoring
A735-01-860 Issue A
Temperature
readings ?V808 0..150 - Decimal °C Measured pump temperature†
0..150 - Decimal °C Measured pump-controller
temperature†
Link parameter
readings ?V809
0..5000 - Decimal 0.1V Measured link voltage
±0..300 - Decimal 0.1A Measured motor current
±0..15000 - Decimal 0.1W Measured motor power
Run hours ?V810 0..99999
~11 years - Decimal Hours Total run hours - time pump has run
Pump cycles ?V811 0..99999 - Decimal Cycles Total number of start/stop
cycles
Drive run time ?V813
0..99999
~11 years - Decimal Hours Total run hours - time pump- controller has run
0..99999
~11 years - Decimal Hours Hours until recommended controller replacement
Time run since
last tip seal
service ?V814
0..99999
~11 years - Decimal Hours Number of pump running
hours since last tip seal
service
Run time to
tip seal
service
indicator
0..99999
~11 years - Decimal Hours
Number of pump running
hours left until tip seal
service due. Decreases until
due at zero
Service
indicator reset !C814 1 - Decimal -
Command to reset service
indicators, 'time since' to
zero and 'time to' to service
interval
Time run since
last bearing
service ?V815
0..99999
~11 years - Decimal Hours Number of pump running
hours since last bearing
service
Run time to
bearing service
indicator
0..99999
~11 years - Decimal Hours
Number of pump running
hours left until bearing
service due. Decreases until
due at zero
Bearing service
indicator reset !C815 1 - Decimal -
Command to reset service
indicators, 'time since' to
zero and 'time to' to service
interval
Fault history 1 ?V816
0..99999
64-bits
encoded as
four 16-bit
words:
<0000..FFFF>;
<0000..FFFF>;
<0000..FFFF>;
<0000..FFFF>
-Decimal
Hexidecimal
Hours
-
Fault history at last trip:
nXDS pump-controller
powered time (hours)
system status register 01;
system status register 02;
warning register 01 and fault
register 01*
Table 3 - Summary of the commands that can be sent to the nXDS pump (continued)
Object name Command Parameter
range Factory setting Data type Units Comments

A735-01-860 Issue A
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Connection for serial control and monitoring
Fault history 2 ?V817
0..99999
64-bits
encoded as
four 16-bit
words:
<0000..FFFF>;
<0000..FFFF>;
<0000..FFFF>;
<0000..FFFF>
-Decimal
Hexidecimal
Hours
-
Fault history at 2nd last trip:
nXDS pump-controller
powered time (hours)
system status register 01;
system status register 02;
warning register 01 and fault
register 01*
Fault history 3 ?V818
0..99999
64-bits
encoded as
four 16-bit
words:
<0000..FFFF>;
<0000..FFFF>;
<0000..FFFF>;
<0000..FFFF>
-Decimal
Hexidecimal
Hours
-
Fault history at 3rd last trip:
nXDS pump-controller
powered time (hours)
system status register 01;
system status register 02;
warning register 01 and fault
register 01*
Fault history 4 ?V819
0..99999
64-bits
encoded as
four 16-bit
words:
<0000..FFFF>;
<0000..FFFF>;
<0000..FFFF>;
<0000..FFFF>
-Decimal
Hexidecimal
Hours
-
Fault history at 4th last trip:
nXDS pump-controller
powered time (hours)
system status register 01;
system status register 02;
warning register 01 and fault
register 01*
Customer
interface
software version ?S820 [1..11] - String ASCII
Characters
Customer interface software
version number (Dxxxxxxxx Y)
(where Dxxxxxxxx is the
drawing number and Y is the
revision)
Factory
settings !C821 1 - Decimal - Reset all configuration
options and parameters to
factory settings
Motor-control
boot-loader
version ?S822 [1..11] - String ASCII
Characters
Motor-control boot-loader
version number
(Dxxxxxxxx Y)
(where Dxxxxxxxx is the
drawing number and Y is the
revision)
Customer
interface
boot-loader
version
?S823 1..11] - String ASCII
Characters
Customer interface boot-
loader version number
(Dxxxxxxxx Y)
(where Dxxxxxxxx is the
drawing number and
Y is the revision)
Table 3 - Summary of the commands that can be sent to the nXDS pump (continued)
Object name Command Parameter
range Factory setting Data type Units Comments

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Connection for serial control and monitoring
A735-01-860 Issue A
Service setting !S825
?S825 0..3 0 Decimal -
0: Service indication on
Service LED
1: Service indication on
Service LED and FAIL line
2: No service indication on
Service LED or FAIL line
3: Service indication on FAIL
line
Service status ?V826 One 16-bit word:
<0000..FFFF> - Hexidecimal - Service status word –
Contact Edwards for more
information‡
Service ?S835 [1..30] - String ASCII
Characters
Serial numbers:
pump; drive-module and
power/control PCA
(fixed at manufacture, 9
characters each)
[1..36] - String ASCII
Characters Pump type and build
*See Section 3.9.1 for status word decoding
†If either returned value is ‘-200’, then this means that this temperature is not utilised within the product
‡See Section 3.9.2 for service word decoding
Table 4 - Command abbreviations
Abbreviation Meaning
cr carriage return character
chars characters
d decimal ASCII character
Note: Fields showing multiple d characters are to indicate typical length. All
data fields have a maximum of 5 decimal characters (prefixed by a minus
number for negative numbers).
h hexadecimal ASCII character
r Returned error code - refer to Table 5
sp space character
string may have several ASCII characters
X Multi-drop decimal ASCII character
Note: Fields showing multiple X characters are to indicate maximum length and
not fixed length.
Table 5 - Error codes
Returned error code Meaning
0 No error
1 Invalid command for object ID
2 Invalid Query/Command
3Missingparameter
4 Parameter out of range
5 Invalid command in current state - e.g. serial command to start/stop when in par-
allel control mode
Table 3 - Summary of the commands that can be sent to the nXDS pump (continued)
Object name Command Parameter
range Factory setting Data type Units Comments

A735-01-860 Issue A
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Connection for serial control and monitoring
3.6 Operating the nXDS pump
3.6.1 Start the pump
To start the pump, send the following command over the serial communications link:
The reply you receive will be in the following format:
The pump will then accelerate up to the target speed and the green run LED will flash whilst it is doing so. When the
pump reaches its target speed, the green run LED will remain illuminated.
3.6.2 Standby speed
To run the nXDS pump at standby speed, send the following command over the serial communications link:
The reply you receive will be as follows:
If the pump is currently below standby speed then it will accelerate until it reaches standby speed. If it is running
faster than standby speed, it will decelerate until standby speed is reached.
To return the pump to full speed, send the following command:
The reply you receive will be as follows:
3.6.3 Stop the pump
To stop the nXDS pump, send the following command over the serial communications link:
The reply you receive will be in the following format:
On successful receipt of the stop command, the pump will decelerate to rest.
Command ! C802sp1cr
Reply * C802sp rcr
Command ! C 8 0 3sp1cr
Reply * C803sp rcr
Command ! C803sp0cr
Reply * C803sp rcr
Command ! C802sp0cr
Reply * C802sp rcr

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Connection for serial control and monitoring
A735-01-860 Issue A
3.7 Multi-drop operation
Using multi-drop mode, a single computer system can communicate with more than one nXDS pump. Each nXDS pump
must be assigned its own individual address, or node, before it can be fitted into a multi-drop system. The command
to assign the multi-drop address is sent in standard nXDS message format and is detailed in Section 3.7.1 below.
The message protocol in multi-drop mode is marginally different to that described for serial messages in single pump
systems (Section 3.4). The main differences in multi-drop message protocol are detailed below:
All multi-drop commands, queries or replies have the start character #.
All multi-drop commands, queries and replies include a header, which contains the address of the node that
the message is to, followed by the address of the node that the message is from.
There is a delimiter character ':' (colon) which separates the two multi-drop addresses in the header.
The remainder of the message (command, query or reply) follows the same protocol as already described for
single pump systems.
The wild card address 99 means 'any' node.
After a nXDS pump has been assigned a multi-drop address, it will ignore any messages inthe format for single pumps.
An individual nXDS pump will remain silent and ignore all command messages unless the multi-drop address matches
its own address.
Figure 5 shows a schematic diagram of an example multi-drop connection system, which can be expanded to
accommodate multiple pumps.
Figure 5 - RS485 multi-drop connections
1. RS485 interface on control equipment or PC
2. nXDS pump logic interface

A735-01-860 Issue A
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Connection for serial control and monitoring
3.7.1 Assigning a multi-drop address
When you receive your nXDS pump it will have multi-drop mode disabled by default. Each individual pump must be
programmed with its own multi-drop address, via a point-to-point connection, before introduction into a multi-drop
network.
Send the following command to assign a multi-drop address (where the 'd' characters represent the address):
Note: The address can be any decimal number from 1 to 98. The address number 0 is used to disable multi-drop
mode. The address number 99 is reserved as a wild card and is used in the query set up detailed later.
The reply you receive will be as follows:
The multi-drop address is stored within the nXDS pump.
You can also send a query to the pump to find out whether it already has a multi-drop address. Send the following
command:
If you receive the reply shown below, your pump has multi-drop mode disabled:
If your pump already has a multi-drop address you will receive no reply and you must then communicate with your
pump in multi-drop message protocol.
Use the following query (using wild card address 99 which means ‘any’ node) to find out the multi-drop address of
the nXDS pump:
The reply you receive will be as follows, where dd denotes the multi-drop address of the pump:
You can disable multi-drop mode by assigning the pump an address 0. To do this, send the following command (where
dd denotes the multi-drop address of the pump and xx denotes the address of the node that is sending the command):
The reply you receive will be as follows:
Once multi-drop mode is disabled, the pump will no longer respond to multi-drop commands.
Command ! S 800spddcr
Reply * S 800sprcr
Reply ? S 800cr
Reply = S 800sp0cr
Command # 99:99? S800cr
Reply # 99:99= S800spddcr
Command # dd:xx! S8 0 0sp0cr
Reply # xx:dd* S8 0 0sp0cr

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Connection for serial control and monitoring
A735-01-860 Issue A
3.8 Mixed parallel and serial operation
You can control the nXDS pump using the parallel interface control inputs and at the same time monitor various pump
parameters using the serial interface. Alternatively you can control the nXDS pump using commands sent over the
serial interface and at the same time monitor the normal signal using the parallel interface. Figure 6 shows a
schematic diagram of an example mixed operation system that would allow you to do this. Many of the individual
functions available in either parallel or serial operations are also availablein mixed parallel and serial operation; but
note that whilst serial enable is active, the parallel standby and fail signals are not available.
The following functions can also be used in conjunction with mixed parallel and serial operation:
Multi-drop operation; described in Section 3.7.
Analogue speed control; described in the nXDS Scroll Pump Instruction Manual (A735-01-880)
For more information on the parallel control and monitoring, please refer to the nXDS Scroll Pump Instruction Manual
(A735-01-880).
Figure 6 - Logic interface connection - mixed parallel and serial operation
You cannot control the nXDS pump using both the parallel and serial interfaces simultaneously. For example, if you
start the pump by sending a start command over the serial interface, you cannot then stop the pump by using the
parallel interface; you must stop the pump by sending a stop command over the serial interface. Similarly, if you
start the pump by using the start / stop switch on the parallel interface, you cannot then stop the pump by using the
serial interface; you must stop the pump by using the start / stop switch on the parallel interface.
1. RS232 interface on control equipment or PC
2. nXDS pump logic interface
3. Start / Stop switch
4. Optional LED indicator - normal speed
5. Current limit resistor for LED

A735-01-860 Issue A
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Connection for serial control and monitoring
3.9 Decoding status words
3.9.1 Decoding system status word
If you are using the serial communications link you will be able to access further information that may be useful for
fault finding. When you send a query to monitor measured motor speed, the pump also returns a system status word.
The send command is as follows:
You will receive the following reply, where the first returned number refers to motor rotational speed in revolutions
per second (Hz):
The system status word returned is made up of 4 separate status words, each made up of 4 hexadecimal digits and
are separated by a semi-colon ';'. The first status word is 'System status register 1', then 'System status register 2',
then 'Warning register' and the final status word is 'Fault register'. To decode each individual status word, you must
convert each hexadecimal digit into a 4-digit binary number. (Table 6 is provided as an aid.) Follow the example
below:
Command ? V802cr
Reply = V802spddd;hhhh;hhhh;hhhh;h h h hcr
2283

0010001010000011
Table 6 - Hexadecimal conversion table
Hexadecimal Binary Decimal
000000
100011
200102
300113
401004
501015
601106
701117
810008
910019
A101010
B101111
C110012
D110113
E111014
F111115