Churchill Nano Link Series User manual

Nano_Link
Nano_Link
TECHNICAL MANUAL
RADIO/LAND LINE TELEMETRY & TELECONTROL SYSTEM
WITH BATTERY-POWER OPTION

Churchill Controls Limited 2009
The contents of this document must not be disclosed to any third party without the written consent of Churchill
Controls Limited, nor are they to be used for any purpose other than to configure and maintain equipment supplied by
Churchill Controls Limited.
No part of this document can be reproduced, transmitted, transcribed, stored in a retrieval system or translated in any
way without the prior written consent of Churchill Controls Limited.
Whilst every attempt has been made to ensure the accuracy of this document, Churchill Controls Limited will not be
held liable for any errors or omissions.
As part of our policy of continuous improvement we would welcome any suggestions for changes to the document.
Churchill Controls Ltd.
30 Wellington Business Park
Dukes Ride
Crowthorne
RG45 6LS
Tel: [phone]
Fax: [phone]
e-mail: [email protected]
website: www.churchill-controls.co.uk
Issue Date Revision
1 05/05/99
2 20/10/00 Adds Exception Reporting
3 21/01/02 Enhances exception reporting and
adds 1 sec transducer warm-up
4 08/06/04 Adds 4 sec warm-up & new radio test
modes, plus various corrections
5 02/02/09 Adds rotation sensor and analogue
averaging modes

TABLE OF CONTENTS
1. PREFACE.........................................................................................................................................................3
2. COMMON FEATURES..................................................................................................................................4
2.1 Mechanical .........................................................................................................................................................4
2.1.1 Housing ..............................................................................................................................................................4
2.1.2 Nano_Link IP67 .................................................................................................................................................4
2.1.3 Polycarbonate Enclosures...................................................................................................................................4
2.2 Network Communications.................................................................................................................................. 5
2.2.1 Radio ..................................................................................................................................................................5
2.2.2 Leased Line ........................................................................................................................................................5
2.2.3 Private Wire .......................................................................................................................................................5
3. PRODUCT DESCRIPTION ...........................................................................................................................6
3.1 General ...............................................................................................................................................................6
3.2 Indicators............................................................................................................................................................7
3.3 Power Supply .....................................................................................................................................................7
3.3.1 Internal Batteries ................................................................................................................................................7
3.3.2 Universal Mains Power Supply.......................................................................................................................... 8
3.3.3 External 12/24VDC Source................................................................................................................................ 8
3.3.4 Solar Supply .......................................................................................................................................................8
3.3.5 External 5V Source ............................................................................................................................................9
3.4 Plant I/O ............................................................................................................................................................. 9
3.4.1 Digital Inputs......................................................................................................................................................9
3.4.1.1 Pseudo Digital Input 1 – Comms Fail alarm....................................................................................................................... 10
3.4.1.2 Pseudo Digital Input 2 – Battery Low alarm ...................................................................................................................... 10
3.4.2 Digital Outputs .................................................................................................................................................10
3.4.3 Analogue Inputs ...............................................................................................................................................11
3.4.3.1 Real Inputs: ........................................................................................................................................................................ 11
3.4.3.1.1 Potentiometer Interface..................................................................................................................13
3.4.3.1.2 Voltage Output Transducers ..........................................................................................................13
3.4.3.2 Pseudo Analogue Input 1 - Supply Volts............................................................................................................................ 14
3.4.3.3 Pseudo Analogue Input 2 - Radio Received Signal Strength Indicator (RSSI)................................................................... 14
3.4.4 Analogue Outputs............................................................................................................................................. 15
3.4.5 Expansion Capability .......................................................................................................................................15
3.4.5.1.1 7150-1 Digital Input Module .........................................................................................................16
3.4.5.1.2 7150-2 Digital Output Module ......................................................................................................17
4. INSTALLATION...........................................................................................................................................18
4.1 Mechanical .......................................................................................................................................................18
4.2 Aerials ..............................................................................................................................................................18
4.3 Surge Protection ...............................................................................................................................................19
5. CONFIGURATION.......................................................................................................................................20
5.1 Switch S1 - Station Address.............................................................................................................................20
5.2 Switch S2 - Mode.............................................................................................................................................20
5.2.1 S2.1 ... S2.5 - Radio Versions – Set Channel ................................................................................................... 20
5.2.2 S2.1 ... S2.5 - Modem Versions – Set Data Rate.............................................................................................. 21
5.2.3 S2.6…S2.8 - Operating Mode..........................................................................................................................21
6. SPECIFICATIONS........................................................................................................................................22
7. NANO_LINK AS AN OUTSTATION..........................................................................................................23
7.1 Operating Modes ..............................................................................................................................................23
7.1.1 Continuous operation (S2.6…S2.8 = 001) .......................................................................................................23
7.1.2 Power-save mode with 250ms transducer settling time (S2.6…S2.8 = 000) ................................................... 23

Page 2
7.1.2.1 Sniff mode.......................................................................................................................................................................... 23
7.1.2.2 Receive Mode..................................................................................................................................................................... 23
7.1.2.3 Transmit Mode ................................................................................................................................................................... 23
7.1.2.4 Sleep Mode......................................................................................................................................................................... 24
7.1.3 Power-save mode with 1 second transducer settling time (S2.6…S2.8 = 110)................................................ 24
7.1.4 Power-save mode with 4 second transducer settling time (S2.6…S2.8 = 101)................................................ 24
7.1.5 Power-save mode with 30 second transducer settling time (S2.6…S2.8 = 100) .............................................. 24
7.1.6 Power-save mode, using digital outputs (S2.6…S2.8 = 010)...........................................................................24
7.1.7 Power-save mode, analogue averaging (S2.6…S2.8 = 011) ............................................................................ 25
7.1.8 Power-save mode, Rotation Sensor (S2.6…S2.8 = 111).................................................................................. 25
7.2 Outstation Alarm Handling ..............................................................................................................................26
8. NANO_LINK AS A BASE-STATION .........................................................................................................27
8.1 Operating Modes ..............................................................................................................................................27
8.1.1 Normal operation..............................................................................................................................................27
8.1.1.1 Continuous transmission (S2.6…S2.8 = 000) .................................................................................................................... 27
8.1.1.2 Slow Scan (S2.6…S2.8 = 010)........................................................................................................................................... 27
8.1.2 Radio Commissioning (S2.6…S2.8 = 001)......................................................................................................27
8.1.3 Radio Path Test Set (S2.6…S2.8 = 011) .......................................................................................................... 28
8.2 Base-station Alarm Handling ...........................................................................................................................29
9. SPECIAL FEATURES OF NANO_LINK...................................................................................................30
9.1 Rotation Sensor ................................................................................................................................................30
9.2 Shaft Encoder Interface....................................................................................................................................30
9.2.1 General .............................................................................................................................................................30
9.2.2 Implementation.................................................................................................................................................30
9.2.3 Hardware Configuration................................................................................................................................... 31
9.2.4 Software Configuration ....................................................................................................................................31
9.3 Exception Reporting.........................................................................................................................................32
9.4 Test Modes ....................................................................................................................................................... 33
9.4.1 Address 255 (S1 = 11111111) - Power down..................................................................................................33
9.4.2 Address 254 (S1 = 01111111) - Test Receiver................................................................................................33
9.4.3 Address 253 (S1 = 10111111) - Test Communications Device ......................................................................33
9.4.4 Address 252 (S1 = 00111111) – Calibrate Analogues / Test Hardware Outputs / Reset Counters .................. 34
10. ALPHANUMERIC DISPLAY MODULE...................................................................................................35
10.1 General .............................................................................................................................................................35
10.2 Operation..........................................................................................................................................................35
10.2.1 Update Number of Shaft Encoders................................................................................................................... 35
10.2.2 Zero Shaft Encoders ......................................................................................................................................... 36
10.2.3 Radio Path Test mode.......................................................................................................................................36
10.2.4 Update Radio Channel......................................................................................................................................36

Page 3
1. Preface
This manual is intended to give the installer, user and maintenance personnel all the information they are likely to need
for implementing telemetry systems from the Data_Link 2000 product range.
The Data_Link 2000 product is based on Nano_Link (which is a simple, low power, self-contained unit) and
Micro_Link (which is a more complex product with considerable expansion capacity and many configurable
functions). This manual concentrates on Nano_Link. If a system uses both Nano_Link and Micro_Link, this manual
should be read in conjunction with the ‘Data_Link 2000 Technical Manual’.
The Data_Link 2000 product range is subject to continuous evolution, so new features are constantly being added by a
combination of software enhancements and new hardware modules. This manual describes the features of Nano_Link
software version 2.24. Some of the features described may not be available, or may function slightly differently, in
earlier software versions. However, it is Churchill Control’s policy to ensure that wherever possible software is
backwards-compatible. This means that wherever possible the features described will be present in all future software
issues.
The software version fitted within Nano_Link can be found by removing the cover and examining the label on the
EPROM, or by connecting an alphanumeric display to it.
Every attempt has been made to lay out this manual in a logical sequence. Chapter 2 describes the features of
Nano_Link, and should be read before designing a system around Nano_Link.
Chapter 4 explains the method of installation.
Chapter 5 describes the method of configuring Nano_Link for each specific application, and chapters 6, 7, 8 and 9
describe the functionality in detail.
Chapter 10 describes the Alphanumeric Display Module, which provides a user interface if required.
Before shipping any Nano_Link system, Churchill Controls configure it to their best understanding of the specific
application requirements, and test it as a complete system. However, because the internal power supply has battery
back-up which would run down during shipping. To overcome this the configuration switches on each Nano_Link are
set to the power down mode immediately prior to shipping. After installation the system should begin operation
immediately if the user sets the switches to the position marked on the label attached to the unit.

Page 4
2. Common Features
2.1 Mechanical
2.1.1 Housing
All modules (except the Nano_Link IP67) are housed in plastic cases, which can be
clipped onto either G or ‘top hat’ DIN rails. The housings measure 125mm H x
125mm W x 110mm D (when mounted on a vertical surface). All electrical
connections are made through two part screw terminals along the top and bottom
edges. Connections between modules and with other devices are made through FCC68
RJ11 and RJ45 jacks. No internal circuitry is accessible without removing the top
cover.
The top cover is retained by internal clips, and can be removed by inserting a fingernail
or screwdriver into the centre of the gap at each side of the cover and pulling outwards.
Some modules also have screws.
To unclip modules from ‘top hat’ rails on a vertical surface, press down on the top of
the module and lift it out from the bottom.
2.1.2 Nano_Link IP67
This is a form of mechanical housing that can be used
when Nano_Link has no ancillary equipment around it. It
is a lower cost option than a conventional unit in a
polycarbonate enclosure.
As shown in the illustration, a leased line unit can also
incorporate a surge protection unit. All variants can also
include any of the power supply options and a rotation
sensor.
A label is attached to the inside of the lid to show the I/O
connections. It also identifies the type of power supply
fitted, and can be used to identify the required DIPswitch
settings.
2.1.3 Polycarbonate Enclosures
A range of polycarbonate enclosures is available for applications requiring wall-mounting. They range in size from
190mm x 190mm x 135mm (suitable for a single module) up to 380mm x 560mm x 135mm (for up to 4 modules). The
smallest enclosure is rated IP68 (submersible for 24 hours to a depth of 2m), whilst all others are IP67 (resistance to
temporary submersion to a depth of 1m). The enclosures are fitted with DIN rails to which the unit can be clipped and a
cable to extend the aerial connector to a TNC aerial socket on the top of the enclosure. It is assumed that the user will
fit any glands needed to bring plant I/O into the enclosure.
It should be noted that the IP rating is dependent on the lid being screwed down tightly, and all glands being correctly
fitted and secured.
Larger systems can be supplied in steel enclosures if required.
PRESS DOWN
PULL OUT

Page 5
2.2 Network Communications
2.2.1 Radio
Both Micro_Link and Nano_Link can be equipped with synthesised VHF or UHF transceivers which are approved to
ETSI standard EN 300 220-1 and can thus be used so can be used in all the European Community member states
(subject to national requirements). In the UK the de-regulated bands are designated MPT1328 (VHF) or MPT1329
(UHF) bands. Any of 32 channels can be selected to avoid conflict with other users.
The UHF MPT1329 band is the most popular, since it allows for transmit powers of up to 500mW ERP (Effective
Radiated Power), but doesn’t require a licence. There are 32 channels at 12.5KHz spacing, in the band 458.500MHz to
458.925MHz.
The radio range depends on the aerials used and the topography of the area, but will typically be up to 8Km in urban
environments and up to 25Km with elevated aerials.
There are two adjustments on the radio modules, Modulation Level and Transmit Power, both of which are factory set:
The Modulation Level trimmer sets the transmitter frequency deviation, and should never be changed.
The Transmit Power trimmer sets the output power in the range 20mW to 1W, and is pre-set to 500mW. It can only be
changed by qualified personnel equipped with a calibrated UHF power level meter. The output level can be set below
500mW to minimise power consumption and reduce potential interference with other users. It must be set below
500mW if the aerial has gain. It can only be set above 500mW if the aerial and/or aerial feeder has an overall gain of
less than unity, and then only to compensate for the losses. The ERP must never be set to more that 500mW when
using MPT1329.
Other versions can be supplied to operate within the regulated MPT1411 band of 457.5MHz to 458.5MHz and
463.0MHz to 464MHz at power levels up to 5W, or the unregulated MPT1328 band of 173.20MHz to 173.35MHz at a
power level of 10mW.
2.2.2 Leased Line
Nano_Link can alternatively be equipped with modems for use on leased telephone lines supplied by national network
providers such as BT and Mercury. The modems are approved for use through the European Union.
The modems are capable of operating with an end-to-end loss of up to 27dB, and provide correct impedance matching
in accordance with the regulations. Normal telephone wires have a loss of about 1.5dB per Km, giving a range of
typically 18Km. However, if more than one outstation is used, the line becomes mismatched, thus increasing the loss
and effectively reducing the maximum line length. This can be overcome by adding line amplification and/or
impedance matching pads. The network provider will normally arrange this.
2.2.3 Private Wire
Private wires are cable pairs similar to leased lines, but owned by the user. The user is thus responsible for
maintenance of the cable, but does not have to pay rental charges.
Over short distance the characteristics of the cable are unimportant. However, for distances greater than around 2Km
the cable should be matched to the terminating impedance of the modems, namely 600. The modems are capable of
operating with an end-to-end loss of up to 27dB. Normal telephone wires have a loss of about 1.5dB per Km, giving a
range of typically 18Km. However, if more than one outstation is used, the line would become mismatched, due to the
additional load impedance. This increases the loss and effectively reduces the maximum allowable line length. A high
impedance version of the modem is available to overcome this and allow large numbers of outstations to be connected
across a single pair of wires, with appropriate terminations at each end of the cable.

Page 6
3. Product Description
3.1 General
Nano_Link is housed in a compact plastic enclosure, which includes an internal power supply and radio or modem, and
can be clipped onto a standard DIN rail. It can be supplied in waterproof polycarbonate enclosures if required.
The internal power supply can be three ‘D’ alkaline batteries, a mains power supply with battery back-up or an external
12VDC source (such as a solar power supply). The module has been optimised for low power consumption, to the
extent that it will operate for over 2 years on low-cost Duracell batteries. Battery operation has the advantage of
significantly lower installation and running costs.
The internal communications device can be either a radio or a modem. The radio is normally operated on a de-
regulated UHF band, so doesn’t need a licence. The modem can use either a leased line (owned by a national network
provider) or a private wire (owned by the user). Nano_Link can also be used with external communications devices
connected to the Comms_Link port.
Nano_Link has 4 digital inputs, which can each be used to monitor alarm or status conditions, and also to count pulses
from totalised flow transducers. Pseudo digital inputs flag communications fail alarm and battery low alarm
conditions. It also has 2 analogue inputs, which can be used with low-cost millivolt transducers or conventional current
loop transmitters. A pseudo analogue input monitors the battery voltage and another monitors the radio receive signal
strength.
Nano_Link can also be equipped with 4 digital outputs, each comprising a volt-free relay contact, and two 0…20mA
analogue outputs. The state of each output can be monitored by LED indicators located adjacent to the relevant
terminals.
The capacity can be increased by a further 16 digital inputs and/or 16 digital outputs by adding optional digital
expansion modules.
Although Nano_Link is intended primarily for use as an outstation or repeater, it can be configured as a base-station to
provide a simple point-to-point link to another Nano_Link, transferring up to 2 analogues and 20 digitals in both
directions.
However, to access pseudo inputs, use repeaters, or use more than one outstation, a Micro_Link base-station should be
used. This is described in the ‘Data_Link 2000 Technical Manual’
N
ano_Link
Aerial
Line
Comms_
Link
(TTL)
I/O_Link
(I
2
C)
85…265VAC 4
5
…
65
Hz 1
0
VA
Internal battery 8…16VDC 0.5A 16…32VDC 0.5A 3…5.5VDC 1A
M
DIGITALS
M
CO
OUTPUTS INPUTS
CO
O/P
12341234
I/P
ANALOGUES
O/P INPUTS
1- 2- + 1- 1I 1+ 2- 2I 2+ -
12345678
Address
SWITCH 1
12345678
Channel Mode
SWITCH 2
Vin
LN
+- I/O +-

Page 7
3.2 Indicators
All Nano_Link’s include four LED’s, designated RXD, TXD, Test and Heartbeat.
TXD and RXD monitor communications between the main processor and the radio or modem. It should be noted that
the radio acknowledges each character sent to it, so whenever the TXD LED flashes on a Nano_Link equipped with a
radio, the RXD flashes in sympathy. This does not happen on Nano_Link’s equipped with other communication
interfaces. In all cases incoming data will cause the RXD LED to flash on its own. Commands to the communications
interface (such as setting the radio channel or enabling the transmitter) are also sent on TXD and acknowledged
through RXD, although they may not result in any transmitted data.
The Test LED lights in normal operation whenever the transmitter is enabled. However, it is also used to indicate when
the unit is in test mode (see 9.3).
The Heartbeat LED flashes to indicate that Nano_Link is ‘alive’. The flashing sequence indicates its status:
When flicking on very briefly every second, Nano_Link is asleep, in its power-down mode.
When flashing continuously at the rate of 4 flashes per second, Nano_Link is awake, communicating correctly,
and its power supply is good.
When flashing three pulses out of every four, Nano_Link is awake, but has lost communication with the remote
device.
When flashing two pulses out of every four, Nano_Link is awake and has communication with the remote device,
but its battery is running low.
When flashing one pulse out of every four, Nano_Link is configured as a base-station, has communication with
the remote device, and its battery is good, but the remote outstation is reporting a low battery.
Nano_Link’s equipped with digital outputs also have 4 LED’s to monitor the state of these outputs. These LED’s are
located adjacent to the relevant terminals.
3.3 Power Supply
Nano_Link works from an input supply of 3.0…5.5VDC, which may be derived from a variety of sources via an
internal power supply unit.
The current consumption is less than 50A when asleep, increasing to about 20mA when awake, and about 1A when
the radio transmitter is active. Nano_Link incorporates is a power converter that generates a stable +5Vsupply when
required for the modem or radio receiver, expansion modules and other digital circuitry, and another that generates
+12VDC when required to power the radio transmitter, modem and/or external analogue transducers. If Nano_Link is
set to power save mode (see 7.1) both converters are disabled when not required to conserve power. However, in
constant power mode (see 7.1) they both remain active at all times.
The output of the internal power supply is accessible through the terminals marked ‘I/O’, which can also be used as the
power input if no internal supply is fitted. The input to the internal power supply is accessible through the terminals
marked ‘Vin’. The label is marked to indicate the type of supply fitted:
3.3.1 Internal Batteries
An internal battery pack can be fitted which holds three D alkaline cells (typically Duracell Procell batteries). These
have a capacity of 18 ampere-hours, which is sufficient to power the unit for at least two years if it is scanned every 15
minutes.
When fitting new batteries, ensure that the negative end (flat) goes to the coil spring in the battery holder.
Battery power is only intended to be used for an outstation that is interrogated relatively infrequently (typically every
15 minutes) or uses exception reporting, and is not intended to support digital or analogue outputs. Furthermore it will
not support expansion modules.
Nano_Link monitors the battery voltage as an analogue value that can be read by the base-station. It also generates a
digital alarm if it drops below a defined level. The outstation should continue working for several days after generating
this alarm (assuming it is interrogated every 15 minutes).

Page 8
3.3.2 Universal Mains Power Supply
An internal mains power pack can be fitted, which derives a 5.3V supply from any input in the range 80…260VAC.
The supply includes rechargeable Ni-Cad batteries, which will support the unit in the event of a mains power failure.
Nano_Link monitors the battery voltage as an analogue value that can be read by the base-station, and generates a
digital alarm if it drops below a defined level. If a mains fail indication is required a mains-operated relay can be used
externally, with its contacts connected to one of Nano_Link’s digital inputs. The period for which the batteries will
support Nano_Link depends on the mode of operation, but will typically be at least 8 hours.
The power supply is double insulated, so does not require a safety earth. The power input is through a two-part screw
connector that is different both in size and colour from all other terminals, to ensure it cannot be incorrectly fitted.
Mains power should be used for any Nano_Link used as a base-station, a repeater or an outstation that is interrogated
continuously, used analogue or digital outputs or is fitted with expansion modules. It can also be used for an outstation
that is interrogated relatively infrequently.
3.3.3 External 12/24VDC Source
Two variants of this supply are available, one operating from a supply in the range 8…16VDC and the other for
16…32VDC. They are intended for operation from station supplies of nominally 12V and 24V respectively. If the
user wishes to monitor the battery voltage, and/or generate a battery low alarm, the 7041 Solar Power Controller
described below can be used by connecting the station battery to it and omitting the solar panel.
3.3.4 Solar Supply
Solar power requires an external solar panel, a solar controller and a lead-acid battery. The battery is required to
maintain the system overnight and during bad weather. Its size has to be calculated, along with that of the solar panel,
to ensure that the system continues operation throughout the year. Factors influencing the size of the panel and battery
include the electrical load, the location and the ambient temperature range. The controller ensures that the battery is not
overcharged during bright sunlight, and does not discharge into the panel at night.
Nano_Link ‘s supplied for solar operation are fitted with an internal 12VDC power supply, and use an external 7041
Solar Power Controller and battery. The controller is fitted in a small housing that clips onto DIN rail adjacent to
Nano_Link. The battery is normally fitted at the bottom of the enclosure. An important feature of the 7041 Solar
Power Controller is its very low internal power dissipation. Some commercially-available solar controllers are
designed for us with large solar panels and batteries, and consume more current than Nano_Link! They therefore
significantly reduce battery life when used on small systems.
As well as controlling charge to the battery, the 7041 Solar Power Controller also provides a digital Battery Low Alarm
output that can be connected directly to one of the digital inputs on Nano_Link. There is also a voltage monitor which
provides a level of 0…100mV for a battery voltage range of 0…20V. This output can be connected to one of the
analogue inputs on Nano_Link if required.
The 7041 Solar Power Controller has two LEDs, marked ‘Charging’ and ‘Charged’. The Charging LED flashes when
the battery is being charged by the solar panel. If the battery attains a fully-charged state the ‘Charged’ LED lights, and
the controller shorts out the solar panel to prevent further charging. In the quiescent state both LEDs will flash
alternately as a trickle charge is fed to the battery to maintain equilibrium.
Whenever the solar panel is not charging the battery (e.g. at night) the Charged LED will flash and the Charging LED
will remain off. If the battery voltage drops below 11V the flash rate will slow to about 1 pulse/second and the Battery
Low Alarm will be generated.

Page 9
Connections to the 7041 controller are via screw terminals, as follows:
Terminals 7 and 8 should be connected to Vin – and + respectively on Nano_Link. Terminal 5 can be connected to any
of the digital inputs on Nano_Link if required. Terminal 6 can be connected to Analogue 1+ on Nano_Link if the
battery volts is to be monitored remotely, with analogue 1- connected to the Analogue – terminal. Do not fit a link
between 1I and 1-. Analogue input 2 can still be used for 0…100mV or 0…20mA signals.
3.3.5 External 5V Source
Nano_Link can alternatively be operated from an external source of 3.0…5.5V. The supply must be capable of
supplying 1A surge currents.
3.4 Plant I/O
All plant I/O on Nano_Link is via screw terminals on two-part connectors. This provides universal connectivity whilst
allowing the unit to be easily replaced if necessary. One connector is allocated for digital I/O and another for analogue
I/O. The pin functions are marked on the top cover.
3.4.1 Digital Inputs
Nano_Link has 4 identical digital inputs, with a common return, intended for use with volt-free contacts. The input
circuit is as follows:
The inputs are intended for use with volt-free contacts, but can also be used to monitor DC voltages in the range
0…24V. A closed contact (or a voltage less than approx. 1V) is treated as logic ‘1’, and an open contact (or a voltage
greater than approx. 4V) is a logic ‘0’.
The series resistors give protection against EMI and excessive voltages in input terminals. The capacitors serve the dual
purpose of providing a surge wetting current when the input contact first closes and providing switch bounce filtering,
whilst allowing pulses of up to 10pps to be counted.
0V
470K
V+
1M
100
COMMON
RETURN
INPUT 100
10n
10n
M
DIGITALS
M
CO
OUTPUTS INPUTS
CO
O/P
12341234
I/P
1 2
3 4
5 6
7 8
1 Solar Panel –ve 2 Solar Panel +ve
3 Battery –ve 4 Battery +ve
5 Battery Low Alarm 6 Battery monitor
7 Output –ve 8 Output +ve

Page 10
V+ is equal to the raw input voltage (i.e. 3.0...5.5V) when Nano_Link is asleep, and 5.0V when it is awake.
Nano_Link records the current state of each digital input. In addition, it maintains an internal 16-bit counter for each
input, which is incremented each time the contact closes. Each input can therefore be used to monitor a digital state or
to count input pulses. The count is copied into non-volatile memory every 10 minutes, so in the event of a total power
failure in the worst case only 10 minutes of counts will be lost.
The counters can be reset to zero using a special test mode (see Chapter 0).
3.4.1.1 Pseudo Digital Input 1 – Comms Fail alarm
This is set to ‘1’ under normal conditions, but changes to ‘0’ in the event of loss of communications. It is described in
more detail in Sections 7.2 and 8.2.
3.4.1.2 Pseudo Digital Input 2 – Battery Low alarm
This is set to ‘1’ under normal conditions, but changes to ‘0’ when Nano_Link senses that the supply voltage is
dropping to the point where failure is imminent. It is described in more detail in Sections 7.2 and 8.2.
3.4.2 Digital Outputs
Digital outputs, if equipped, use volt-free relay contacts rated 125VAC/0.5A/60VA max. or 24VDC/1A/30W max.
The four outputs share a common return, but are fully isolated from the internal circuitry.
Note that the digital outputs copy the state of the corresponding remote digital inputs, combined with alarm flags as
described in 7.2 and 8.2.
Although the relay contacts are rated up to 125VAC, the user must exercise due caution to ensure that the safety
requirements of the Low Voltage Directive are not breached by the application of an unsafe voltage from an external
source.
If the relays are used to switch inductive loads, such as interposing relays, the load must include transient suppression
to prevent excessive voltages during switching. If the load is DC, this is most easily achieved by connecting a reverse-
biased diode across the load. If it is AC, a bi-directional suppressor such as transorb or a voltage dependent resistor
should be used
M
DIGITALS
M
CO
OUTPUTS INPUTS
CO
O/P
12341234
I/P

Page 11
3.4.3 Analogue Inputs
Nano_Link has two real inputs and two pseudo inputs (which read the battery voltage and the radio received signal
strength):
3.4.3.1 Real Inputs:
The two real inputs are very similar, and are read to a resolution of 12-bits (i.e. 0…4095). The equivalent circuit of
input 1 is as follows:
Analogue input 2 is identical, but omits the SENSE detector.
Nano_Link generates an internal 12V supply, which is present all the time if the unit is configured for mains power,
but switched off in battery-powered units when not needed, to conserve power. It is used to power the analogue input
and output circuits, and the radio transmitter. It is also available for powering transducers if required.
If SENSE is within 1V of either 0V or 12V the input sensitivity is set to 0...100.0mV. Linking 1I to 1+ converts this to
a current input of 0...20.00mA. This is compatible with both 0…10mA and 4…20mA transducers, and can detect both
over-range and under-range errors. The means of connecting current transducers is thus:
A N A L O G U E S
O / P I N P U T S
1 - 2 -
+
1 -
1 I
1 +
2 -
2 I
2 +
-
2-wire current transducer input,
powered by Nano_Link
+ -
+ -
A N A L O G U E S
O / P I N P U T S
1 - 2 -
+
1 -
1 I
1 +
2 -
2 I
2 +
-
2-wire current transducer input,
externally powered
+ -
+ -
0V
External supply
+10…24V
0V
10Vsw
+
-
SENSE
Vou
t
1M
1M
1-
1I
-
+
1+ 1M
27K
47

H
47

H
5

27K

Page 12
The calibration means that a reading of 4000 corresponds to full scale. A reading between 4001 and 4095 indicates that
the input is over-range.
If SENSE is midway between 0V and 12V, Nano_Link assumes the transducer to be a strain gauge pressure sensor.
These give an output voltage that is proportional to the supply voltage and to the pressure, and are normally calibrated
to give 100mV FSD when powered from 12VDC. Nano_Link accommodates this by changing the reference to 1.00%
of 12V. It thus self-adjusts for tolerances on 12V:
Note that the 12V supply from Nano_Link is only present when the station is awake. A base-station is
constantly awake, as is an outstation in Constant Power Mode. However, a battery-powered outstation
conserves power by only energising the transducers when needed. It will thus activate the 12V supply only when
it receives a command requesting an analogue reading. The supply is then raised for a short period before
sampling the analogue, to give the transducer time to stabilise. Power is switched off immediately after the
response has been sent to the base-station.
If the user wishes to test transducers at a battery-powered site, he should set the station to constant power mode for the
duration of the tests, remembering to return it to normal afterwards to conserve the battery.
For more information on operating modes refer to Chapters 7 and 8.
A N A L O G U E S
O / P I N P U T S
1 - 2 -
+
1 -
1 I
1 +
2 -
2 I
2 +
-
3-wire current transducer with common 0V,
powered by Nano_Link
+ -
O/P
+ -
O/P
A N A L O G U E S
O / P I N P U T S
1 - 2 -
+
1 -
1 I
1 +
2 -
2 I
2 +
-
3-wire current transducer with common 0V,
externally powered
+ -
O/P
+ -
O/P
0V
External supply
+10…24V
A N A L O G U E S
O / P I N P U T S
1 - 2 -
+
1 -
1 I
1 +
2 -
2 I
2 +
-
4-wire strain gauge transducer,
powered by Nano_Link
+ -
A
B
+ -
A
B

Page 13
3.4.3.1.1 Potentiometer Interface
Some transducers incorporate a potentiometer that needs to be energised by a stable voltage, and returns a voltage that
varies from 0 to 100% of the energising voltage. A small interface module, designate 7023-1 is available to power a
potentiometer from a stable supply derived from the analogue + & - output from Nano_Link, and convert the
potentiometer reading to a 0…100mV signal compatible with the analogue inputs on Nano_Link. The module is fitted
in a small housing that clips onto DIN rail adjacent to Nano_Link and incorporates Span and Offset adjustment.
Details of connections to this module, and the method of calibrating it, are given in Application Note AN009.
3.4.3.1.2 Voltage Output Transducers
A small number of transducers generate a voltage output, typically scaled 1…5VDC. A small interface module,
designate 7023-2 is available to convert this to a voltage in the range 0…100mV, compatible with the analogue inputs
on Nano_Link. The module is fitted in a small housing that clips onto DIN rail adjacent to Nano_Link and
incorporates Span and Offset adjustment.
Details of connections to this module, and the method of calibrating it, are available on request.

Page 14
3.4.3.2 Pseudo Analogue Input 1 - Supply Volts
Nano_Link measures the internal battery voltage, and stores it as if it was an additional analogue input. This register
be accessed in two ways:
1. Using the Alphanumeric Display Module (described in section 10). This scales the register contents and displays
the actual voltage.
2. By configuring Nano_Link as an outstation and interrogating it with a Micro_Link base-station. The method of
accessing the register via Micro_Link is given in the ‘Data_Link 2000 Technical Manual’.
The battery voltage can be calculated from the reading using the formula
Battery = Value / 800V
This can be illustrated graphically as follows:
The reading is limited to the range 0…4080, corresponding to a voltage range of 0…5.10V.
Battery-powered units use 3 alkaline batteries giving a nominal 4.5V (i.e. reading of 3600). When they are nearing the
end of their life the voltage drops to 3.65V (corresponding to a reading of 2920). At this point a battery-powered
Nano_Link will generate a Low Battery alarm.
Mains powered units derive a supply of 5.5V when mains is present, giving a full-scale reading of 4080. If the mains
supply fails the unit continues operating from internal trickle-charged Nickel Cadmium batteries, but the voltage will
drop to about 4.5V (reading 3600). When the batteries are approaching the end of their life the voltage will drop to
4.0V (3200). At this point a mains-powered Nano_Link will generate a Low Battery alarm.
3.4.3.3 Pseudo Analogue Input 2 - Radio Received Signal Strength Indicator (RSSI)
If Nano_Link uses radio communication, it measures the received signal strength, and stores it as if it was an additional
analogue input. This register be accessed in three ways:
1. Using the Alphanumeric Display Module (described in section 10). This scales the register contents and displays
the actual RSSI level in dBµV.
2. By setting a Nano_Link base-station to the radio commissioning mode described in Chapter 8.1.2. The value will
then be presented on an analogue output.
3. By configuring Nano_Link as an outstation and interrogating it with a Micro_Link base-station. The method of
accessing the register via Micro_Link is given in the ‘Data_Link 2000 Technical Manual’.
The RSSI can be used to deduce the margin by which the path can deteriorate before communication will be lost. RSSI
is measured in dBµV, according to the following formula:
RSSI=Value/100-15dBµV
0
1
2
3
4
5
0 1000 2000 3000 4000
Value
Battery Volts

Page 15
This can be illustrated graphically as follows:
The calculated value can be read via Micro_Link. If using method 3 above. However, if using method 1 or 2 the value
will be scaled appropriately.
The radio receiver has a sensitivity of about -10dBV, and a good radio path should have a margin of at least 10dBµV
so the RSSI should ideally read at least 0dBµV, or 1500.
3.4.4 Analogue Outputs
Analogue outputs, if equipped, sink a current of 0…20.00mA to the internal 0V rail. The current can be sourced from
either the internal 12V supply on the + terminal of the analogue connector, or from an external supply of up to 24V DC.
Analogue outputs are only available when the 12V supply is active, so Nano_Link must be set to continuous power
(switch 2.8 closed):
Although the outputs are calibrated to give 0…20.00mA, they can produce up to 20.40mA to indicate fault conditions.
3.4.5 Expansion Capability
Nano_Link includes an I/O_bus port that can be used to access expansion modules from the Data_Link 2000 product
range. Its capacity is limited to one 16-way digital input module (must be set to address 0, so S1.1…S1.5 all open), one
16-way digital output module (must be set to address 1, so S1.1…S1.4 all open, S1.5 closed) and/or an Alphanumeric
Display Module. Digital expansion modules cannot be used on battery-powered Nano_Link’s. The Alphanumeric
Display Module is described in Chapter 10.
-15
-10
-5
0
5
10
15
20
25
0 1000 2000 3000 4000
Value
RSSI (dBuV)
A N A L O G U E S
O / P I N P U T S
1 - 2 -
+
1 -
1 I
1 +
2 -
2 I
2 +
-
Outputs powered by Nano_Link
Load 0…450
- +
- +
A N A L O G U E S
O / P I N P U T S
1 - 2 -
+
1 -
1 I
1 +
2 -
2 I
2 +
-
Outputs powered by external supply
Load 0…((V-1)*50)
- +
- + +10…24V 0V
External Supply

Page 16
3.4.5.1.1 7150-1 Digital Input Module
This module has 16 inputs, each with two terminals marked ‘+’ and ‘-’. The input circuit of each is as follows:
The inputs are designed for use with volt-free contacts, which are supplied a wetting current of 50mA on closing, with
a normal sense current of 250A. However, they can also be used to monitor a DC voltage of up to 24V relative to 0V.
The module usually generates a logic ‘0’ state when the contact is open or the monitored voltage is greater than 3.5V,
and a logic ‘1’ state when the contact is closed or the voltage is less than 1.5V. However, the sense can be inverted if
required by setting switch 8 of the DIPswitch ON. This can be summarised as follows:
Logic State
Input State Switch 8 OFF Switch 8 ON
Volt-free contact open 0 1
Volt-free contact closed 1 0
Sense voltage > 3.5V 0 1
Sense voltage < 1.5V 1 0
The module draws minimal current from the power supply.
Specifications
CURRENT CONSUMPTION: 12V: 0mA
5V: 10mA max.
INPUT VOLTAGE: Logic 0: min. -24V max. +1.5V
Logic 1: min. +3.5V max. +24V
ENERGISING CURRENT: 50mA wetting current, 250A continuous
0V
22K
+5V
1M
100
-
+
100
0

1
D
igital Input Module
I/O_Link
(I 2C)
-+-+-+-+
4321
INPUTS
I/O_Link
(I 2C)
-+-+-+-+
8765
INPUTS
INPUTS
9101112
+-+-+-+-
16151413121110987654321
INPUTS
13 14 15 16
+-+-+-+-
12
V
I/O
+-
SWITCH 1
Address Mode
12345678

Page 17
3.4.5.1.2 7150-2 Digital Output Module
This module has 16 fully isolated outputs. Each comprises a volt-free relay contact rated 125VAC/1A/60VA max.
60VDC/1A/30W max. A 120V transient suppressor is fitted across each contact to prevent damage and/or interference
when switching inductive loads. Each contact is isolated to 500V min from all other contacts and from 0V.
Although the switch contacts are rated at up to 125V, it is the user’s responsibility to ensure that external power sources
do not compromise the operator’s safety.
The module usually closes the contact for logic ‘1’ state and opens it for logic ‘0’. However, the sense can be inverted
if required by setting switch 8 of the DIPswitch ON. This can be summarised as follows:
Output State
Logic State Switch 8 OFF Switch 8 ON
0 OFF ON
1 ON OFF
The module draws a maximum of 240mA from the power supply when all outputs are on.
Specifications
CURRENT CONSUMPTION: 12V: 225mA max. (All outputs on)
5V: 10mA max.
SWITCH RATING: 125VAC/1A/60VA max. 60VDC/1A/30W max.
ISOLATION: 500VAC
D
igital Output Module
I/O_Link
(I 2C)
B
A
B
A
B
A
B
A
4321
OUTPUTS
I/O_Link
(I 2C)
B
A
B
A
B
A
B
A
8765
OUTPUTS
OUTPUTS
9101112
A
B
A
B
A
B
A
B
16151413121110987654321
OUTPUTS
13 14 15 16
A
B
A
B
A
B
A
B
12
V
I/O
+-
SWITCH 1
Address Mode
12345678

Page 18
4. Installation
4.1 Mechanical
Data_Link 2000 outstations and base-stations are usually supplied in either steel or polycarbonate enclosures that can
be attached to a wall using conventional fixings. The smaller polycarbonate enclosures provide a high degree of
protection against water ingress, and care is needed to ensure this isn’t compromised by the method of installation.
Most enclosures include cable glands, which are supplied with blanking plugs to maintain a seal. The sealing plugs
must be removed before feeding cables through the glands, and the glands should be tightened around the cables to
maintain the seal. Blanking plugs should be left in any unused glands.
4.2 Aerials
The four types of aerial commonly used on Data_Link 2000 are whips, end-
fed dipoles, folded dipoles and yagis. Whips and end-fed dipoles are omni-
directional (radiate equally in all directions), so their orientation is not
important. Whip aerials are usually attached directly to Nano_Link or
Micro_Link, or to the top of the enclosure in which they are mounted.
ENF450 end-fed dipole aerials fit into the top of a 2” (OD) pole mounted
externally. CDF450 centre-fed dipoles are useful for mounting on the side
of a pole when the top is not available for an ENF450. Although they
radiate in all directions, the signal is slightly stronger in the direction in
which the balun is pointing (i.e. out of the page, towards the reader, in the
illustration shown).
Yagis are similar to end-fed dipoles, but with reflectors which focus the
signal in the direction in which they are pointing (i.e. to the left in the
illustration shown). This results in signal gain in one direction, at the
expense of loss in all other directions. The directivity and hence gain is
related to the number of elements. A typical yagi, the UHF8, has 8 elements and a gain of
10dB.
Note that approval regulations limit the maximum effective radiated power (ERP) that can
be emitted from a transmitter. If a yagi is used the transmitter output power should be
reduced to compensate for the aerial gain. The aerial gain, however, effectively increases
the sensitivity of the receiver, hence increasing the permissible path loss. Since
Data_Link 2000 uses two-way radio communication, there will be no operational benefit
in fitting a yagi at one end and an omni-directional aerial at the other, since this would
only improve transmission in one direction.
All aerials should be vertically polarised (i.e. the elements should
be vertical, not horizontal). Yagis and end-fed dipoles also have a
defined top and bottom. They must be installed in the orientation
marked by labels attached to them.
External aerial poles can be fixed to walls using either CS6 or SAB
brackets. CS6 brackets space the pole 6” from the wall. SAB
brackets allow the poles to be spaced further from the wall to clear
soffits and gutters, as well as providing a stronger fixing capable of
supporting longer poles.
UHF8
CDF450
SAB
CS6