Westermo RM-505U-2-E User Manual
505U Radio Telemetry Module
User Manual
505U Radio Telemetry Module
ELPRO Technologies Pty Ltd , 9/12 Billabong Street, Stafford Q 4053, Australia.
Tel: +61 7 33524533 Fax: +61 7 33524577 Email: sales@elpro.com.au
Web: www.elpro.com.au
MAN_505_1.7.DOC Page 1
505U Radio Telemetry Module
Thank you for your selection of the 505U module for your telemetry
needs. We trust it will give you many years of valuable service.
ATTENTION!
Incorrect termination of supply wires may
cause internal damage and will void warranty.
To ensure your 505U enjoys a long life,
double check ALL your connections with
the user’s manual
before turning the power on.
Page 2 © September 2002
User Manual
WARNING
1. For 505U modules, a radio licence is not required in most countries, provided the module is
installed using the antenna and equipment configuration permitted. Check with your local
505U distributor for further information on regulations.
2. For 505U modules, operation is authorised by the radio frequency regulatory authority in
your country on a non-protection basis. Although all care is taken in the design of these
units, there is no responsibility taken for sources of external interference. Some delay in the
operation of outputs may occur during periods of interference. Systems should be designed
to be tolerant of these delays.
3. To avoid the risk of electrocution, the antenna, antenna cable, serial cables and all terminals
of the 505U module should be electrically protected. To provide maximum surge and
lightning protection, the module should be connected to a suitable earth and the antenna,
antenna cable, serial cables and the module should be installed as recommended in the
Installation Guide.
4. The 505U module is not suitable for use in explosive environments without additional
protection.
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505U Radio Telemetry Module
505U Radio Telemetry Module
USER MANUAL
1 OVERVIEW -----------------------------------------------------------------------------------------------6
1.1 AVAILABLE MODELS.....................................................................................................6
1.2 I NPUT SIGNALS..............................................................................................................6
1.3 POWER SUPPLY...........................................................................................................7
1.4 RADIO TRANSMITTER....................................................................................................7
1.5 CONFIGURATION ...........................................................................................................8
2 OPERATION----------------------------------------------------------------------------------------------9
2.1 NORMAL OPERATION....................................................................................................9
2.2 WHAT INFORMATION IS TRANSMITTED OVER THE RADIO?...........................................9
2.3 HOW OFTEN IS THE INPUT INFORMATION SENT BY RADIO?.........................................9
2.3.1 Digital Inputs......................................................................................................10
2.3.2 Pulse Inputs........................................................................................................10
2.3.3 Analogue Inputs.................................................................................................11
2.3.4 Setpoint Status...................................................................................................13
2.3.5 Low Battery Voltage Alarm...............................................................................13
2.3.6 Communications Failure..................................................................................13
2.4 HOW TO DESIGN A REMOTE MONITORING SYSTEM .................................................14
2.4.1 Achieving reliable radio transmission............................................................14
2.4.2 How far will the radio transmit? ........................................................................15
2.5 CALCULATING POWER CONSUMPTION......................................................................16
3 HARDWARE INSTALLATION -------------------------------------------------------------------19
3.1 HOW TO MOUNT THE 505U........................................................................................20
3.2 ANTENNA I NSTALLATION.............................................................................................20
3.3 CONNECTION PLUG ....................................................................................................24
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User Manual
3.4 POWER SUPPLY I NSTALLATION..................................................................................26
3.4.1 External Power (Models 505U-x-E)................................................................26
3.4.2 Internal Battery Power (Models 505U-x-B)....................................................26
3.5 I NPUT SIGNAL CONNECTIONS.....................................................................................28
3.5.1 Digital/Pulse Inputs...........................................................................................28
3.5.2 Shaft Encoder Connections.............................................................................29
3.5.3 Analogue input (505U-2 only).........................................................................29
3.5.4 RS232 serial port...............................................................................................29
4 CONFIGURATION------------------------------------------------------------------------------------31
4.1 I/O MAPPING...............................................................................................................32
4.2 UPDATE TRANSMISSION TIMES..................................................................................32
4.3 DIGITAL I NPUTS...........................................................................................................33
4.4 ANALOGUE I NPUT........................................................................................................33
4.5 ANALOG SETPOINTS...................................................................................................34
4.6 PULSE I NPUTS.............................................................................................................35
4.7 NUMBER OF TRANSMISSIONS ....................................................................................36
PROGRAMMING CONFIGURATIONS TO MODULES...................................................................36
4.9 LOADING CONFIGURATION FROM A MODULE.............................................................37
4.10 PRINT OPTIONS...........................................................................................................37
5 TROUBLESHOOTING ------------------------------------------------------------------------------38
6 SPECIFICATIONS------------------------------------------------------------------------------------41
7 WARRANTY--------------------------------------------------------------------------------------------45
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505U Radio Telemetry Module
1 OVERVIEW
The 505U radio telemetry module is an economical solution for the remote monitoring of process
signals. The 505U can connect to digital, pulse or analogue signals from process transducers, and
transmit these signal values by radio.
Although the 505U is intended to be simple in its application, it also provides many sophisticated
features. This manual should be read carefully to ensure that the modules are configured and
installed to give reliable performance. The 505U uses the 105U module as a receiver, or repeater.
If you have not used 105U modules before, please read the 105U User Manual prior to reading
this manual.
The 505U module is a monitoring only unit - that is, it will only accept input signals and does
not provide output signals. The 505U has an internal radio transmitter; it does not have a receiver to
receive messages from another module.
The 505U transmits the value of an input signal whenever the signal changes, and also after a preconfigured time. Each transmission message includes error-checking to confirm the validity of the
message. At each transmission, the 505U may be configured to repeat the transmission several
times to ensure that the transmission is received correctly. This is important if the radio path is
marginal (that is, the radio signal is not strong) or if there is a lot of radio traffic on the radio channel
which may corrupt the 505U message. The 505U transmits the input message to a 105U module,
which sets an output signal to be the same value as the 505U input, or the 105U passes the input
message to another device (PC or PLC) via its serial port.
For more information on the 105U module, please refer to the 105U User Manual.
1.1 Available Models
The 505U has a heavy duty painted aluminium enclosure, weather-proof to IP66. Signal and power
connections to the unit are made via a weatherproof connector at the bottom of the module.
Antenna connection is made using a BNC coaxial connector at the top of the module.
External 12VDC supply
505U-2-E two digital/pulse inputs plus one analogue input
3.5 – 5VDC battery supply (batteries not included)
505U-2-B two digital/pulse inputs plus one analogue input
1.2 Input Signals
The 505U-2 model provides two digital/pulse inputs and one analogue input for connecting to
process transducers.
Digital Signals
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User Manual
Examples: motor fault, tank overflow, intruder alarm
Pulse signals - use the same input as the digital input
Examples: electricity metering, fluid flow, raingauge
Analogue continuously variable signals (0-20mA, 4-20mA, 0-10mA) - 505U-2 only
Examples: measured tank level, measured process temperature
Two internal signals may also be transmitted to outputs in the network:
• Setpoint Status (digital signal set or reset depending upon the value of the analogue signal
compared to a high and a low setpoint value configured in the 505U)
• Battery Low Voltage (digital signal set when internal battery voltage is low).
1.3 Power Supply
The power consumption of the 505U is very small as it conserves power by reverting to “sleep”
mode between transmissions.
The 505U can be powered from an external 12V DC supply, or a 3.5 – 5V battery supply. The
battery supply can be either internal AA alkaline or lithium batteries, or an external battery pack.
The 505U-2-B units provide an internal alarm on low battery voltage - this alarm may be transmitted
by radio for warning purposes. No low battery alarm is provided on externally powered models
(505U-2-E). The low battery alarm indicates that there is approximately 2% of battery capacity
left.
1.4 Radio Transmitter
The 505U has an internal radio transmitter that operates on unlicensed radio channels in the 400 –
500MHz UHF band. A radio licence is not required for the 505U in many countries and has an
operating range of several kilometres.
It is suitable for use in utility industries such as electricity, water and gas, as well as a cost effective
solution for short range applications in factories and industrial plants.
The transmitter is preset in the factory to suit the unlicensed frequency requirements in each country.
The maximum transmitter power is 500mW using an external power supply, or 250mW using the
internal battery supply (500mW available using a 3dB antenna). In countries where there are no
unlicensed radio channels, a radio licence may be required each time the product is used. Please
contact one of our worldwide distributors for further information.
To extend radio range , 105U modules can be used as repeaters. Up to five repeaters can be
configured for each input-to-output link. The configuration is done at the 505U module where the
input signal is - no additional configuration is required at the 105U modules. The transmitted radio
message will include the address of repeater modules - modules with these addresses will retransmit the messages.
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505U Radio Telemetry Module
1.5 Configuration
Each module must be configured before it can be used. Configuration is performed using a PC (or a
laptop computer) connected to the module via the internal RS232 port on the 505U. 505U
configuration software is required and is provided with each order.
Configuring a module requires the entering of “input mappings” and setting operating parameters for
each input. An “input mapping” links an input signal to an output channel at a remote module (or a
“destination address”). An input mapping is entered for each input signal (external and internal)
which is used.
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User Manual
2 OPERATION
2.1 Normal Operation
Once configured using the 505U configuration software, the 505U module will normally be in
“sleep” mode to conserve power. During sleep mode, the microprocessor controller powers down,
and the analogue loop supply is turned off. The microprocessor will automatically “wake up” and
revert to full operation if a digital/pulse input changes (on to off, or off to on), or every 0.5 seconds
to check if a timed update transmission is due to be sent.
Normal operation of the 505U is indicated by a brief flicker of the OK LED light on the front panel
approximately every 10 seconds.
2.2 What information is transmitted over the radio?
The 505U modules transmit the value of the input signal in a data frame. The data frame includes a
system address, and the "address" of the transmitting (source) 505U module and the receiving
(destination) 105U module, so that each transmitted message is acted on only by the correct
receiving unit. The system address is a common address used by all modules in the same system.
This allows multiple systems to operate within the same radio range without "cross-talk" between
systems.
The user configures these addresses as part of the module configuration. Each transmitted message
also includes error checking to ensure that no corruption of the data frame has occurred due to noise
or interference. If repeater modules are being used, then the addresses of these intermediate
modules are also included in the data frame.
The user can configure the 505U to transmit each message from one to five times to ensure that at
least one of the messages is received correctly. Each repeat transmission will occur at random
intervals between one and four seconds.
2.3 How often is the input information sent by radio?
• Change messages. The 505U transmits the value of an input signal whenever the signal changes.
• Update messages. The input value is also transmitted if the signal has not changed within a pre-
configured update time (configurable 10 seconds to 5 days).
• Paralysis. When a 505U transmits a message for a particular input, the 505U will not transmit
another message for this input within a configured time period. This time is called the paralysis
time, and may be used to prevent a lot of messages being transmitted if an input changes
frequently. The paralysis time may be set from zero to 127.5 seconds for each input. For
example, assume the paralysis time on an input is 30 seconds. If the input changes, then the
505U will transmit a message, however it will not transmit another message for this input during
the next 30 seconds, regardless of changes to the input signal. Note that paralysis time does not
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505U Radio Telemetry Module
stop re-transmissions of each message - if the 505U is configured to transmit each message
three times, then paralysis will not stop this.
Depending on the type of input signal (digital, pulse or analogue), the 505U must determine what
type of signal change is required to send a transmission:
2.3.1 Digital Inputs
A digital input can be an external digital input or an internal status input (setpoint status or low
battery alarm).
The 505U will transmit the value of the digital input whenever it changes from off to on or from on to
off. A paralysis time may be configured to prevent another transmission within this time. The 505U
will also transmit an update message if a message has not been transmitted for that input within an
“update time”.
There are two update times for each digital input - one for when the input is on, and one for when
the input is off. Each update time may be configured between 10 seconds and 5 days. For
example, a digital input may be configured to update every 1 day when the input is off, but update
every 10 minutes when the input is on. If an update time of zero (or less than 10 seconds) is
selected, then no update messages will be sent.
Overview:
• Input value transmitted on input change
• Update message if the input value has not been transmitted within the configured update time for
that input (10 seconds - 5 days)
• Separate update times for on and off status for digital inputs
• After each transmission, further transmission for that input is disabled for the paralysis time (0 –
127.5 sec).
2.3.2 Pulse Inputs
Each pulse input is counted and the total count value is transmitted as a 16-bit value. A “sensitivity”
value is configured for each pulse input (0 - 32 000). Whenever the pulse count has increased by
this value since the last transmission, the 505U will transmit the new pulse count. In addition, an
update transmission of the pulse count will be transmitted if the pulse count has not been transmitted
for the update time. If an update time of zero is selected, then no update messages will be sent.
When the 105U receives the input count message, it will compare the input count to its own output
count (the count of output pulses), and will then output pulses until the two counts are the same.
The maximum pulse input is 100Hz (3 msec minimum on-time and off-time). There is no minimum
pulse rate. For pulse rates higher than 1Hz, the power consumption will increase slightly. For pulse
rates higher than 10 Hz, the “Fast Pulsed Inputs” option should be selected. This increases power
consumption of the module further.
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User Manual
If the pulse input message is sent to a host device, it is important to note that the count value
transmitted is an absolute value. The only time that it resets is when the 16-bit accumulator "rolls
over" (exceeds 65 535).
Overview:
• Pulse inputs are counted.
• Pulse count is transmitted when the count has increased by the sensitivity amount since the last
transmission.
• Update message if the input value has not been transmitted within the update time (10 seconds -
5 days).
• After each transmission, another transmission for that input is disabled for the paralysis time (0 –
127.5 sec).
Two pulse inputs may be configured to control one count value, for use with quadrature and
incremental shaft encoders. A shaft encoder is a transducer that measures level or displacement,
and has two pulse signals to indicate change of level and direction of change.
Both pulse inputs are read at the same time.
If using an incremental encoder, the count is the value of Pulse Input 1. This pulse input value should
be used to send the true pulse count from a incremental encoder.
If using a quadrature encoder, the count is the value of Pulse Input 2. This pulse input value should
be used to send the true pulse count from a quadrature encoder.
2.3.3 Analogue Inputs
The analogue input uses a “sample time” and “warm-up time” configured by the user. The sample
time (1 minute to 20 days) “wakes” the 505U from sleep mode and turns on the analogue loop
supply. The “warm-up time” (0.5 – 127.5 seconds) allows the transducer to reach rated accuracy
before the 505U makes a measurement of the analogue signal.
For example, if the sample time is 30 minutes and the warm-up time is 10 seconds, then every 30
minutes, the 505U will turn on its analogue loop supply and after a further 10 seconds, take a
measurement of the analogue signal. After the measurement is taken, the 505U reverts to sleep
mode. The loop voltage available for a transducer is approx 1.5V less than supply voltage for
externally powered models or 8.5V for battery powered models.
If the sample time is set to zero, then the analogue loop supply will be on continuously and
measurement will be taken based on the warm-up time. If the warm-up time is 1 second, then a
measurement is taken every 1 second.
The same process occurs if an externally powered analogue signal is connected.
The measurements have a resolution of 12 bit, and an overall accuracy of better than 0.1%.
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505U Radio Telemetry Module
When the 505U takes a measurement, it will transmit the analogue value if the value has changed by
more than the pre-configured sensitivity since the last transmission. The sensitivity can be
configured from 0.25% to 100% (0.05mA to 20mA) with a default value of 3% (0.6mA). If the
change in the signal since the last transmitted value is less than the sensitivity, then the 505U will not
transmit the analogue value.
In addition, an update transmission of the analogue value will be transmitted if the analogue value has
not been transmitted for the update time (10 seconds - 5 days). If an update time of zero is
selected, then no update messages will be sent.
If the update time expires since the last transmission, then the last measured value will be transmitted
- that is, a new measurement will not be taken. Normally the update time will be much longer than
the sample time. If the update time is less than the sample time, then update messages may transmit
the same value as the previous transmission, as a new measurement has not yet been taken.
Overview:
• Measurements of the analogue signal are determined by the sample time and warm-up time
• Analogue value is transmitted if the measured value has increased by the configured sensitivity
amount since the last transmission
• Analogue value is transmitted if the input value has not been transmitted within the update time
(10 seconds - 5 days)
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2.3.4 Setpoint Status
The setpoint status is an internal status value, calculated by comparing the analogue input to two
configurable setpoint values. The setpoint status turns ON when the analogue input moves below
the low setpoint value, and turns OFF when it moves above the high setpoint value. The high
setpoint percentage must always be greater than, or equal to, the low set point.
The internal setpoint status will be determined every time an analogue measurement is taken.
The setpoint status is treated as a digital signal and its value is transmitted according to the rules for a
digital input.
2.3.5 Low Battery Voltage Alarm
If the voltage of the internal battery supply falls below 2.9 volts, the internal battery voltage alarm
will turn on.
The Low Battery Voltage Alarm is treated as a digital signal and its value is transmitted according to
the rules for a digital input.
When the a low battery condition occurs, the low battery status will need to be reset - refer to
section 5 of this manual.
2.3.6 Communications Failure
The 505U cannot provide an indication that its transmitted messages have not been received
successfully.
This indication is however available at the receiving 105U by using the 105U Output Reset on
Comms Fail function. To use this function, map an input that is not being used on the 505U to a
spare output on the 105U. The unused input can be an internal input such as the Low Battery status
or Setpoint status, or even the analogue input as this can also be mapped to a digital output.
Configure the 505U so that the digital output at the 105U is normally on - you can configure an input
to output mapping to be inverted or direct.
If you configure a reset time to the 105U output, then this output will turn off if it has not received an
update message from the 505U within that time. The 105U output is effectively a "Communications
OK" output - on when communications are OK, and off during communications failure. Note that
the maximum output reset time at the 105U is 32 minutes, so the update time for the 505U input
must be less than this. It is generally a good idea to set the update time to less than half of the reset
time. Then, the 105U must fail to receive two consecutive update messages - it is possible to miss
one update message because of random noise, but two consecutive failures means that there is a
system failure. For example, if you wish to have a failure alarm within 10 minutes of a system failure,
set the output reset time at the 105U to 10 minutes and the update time at the 505U to 4.5 minutes.
MAN_505_1.7.DOC Page 13
505U Radio Telemetry Module
Probability of successful transmission
2.4 How to Design a Remote Monitoring System
2.4.1 Achieving reliable radio transmission
A system can theoretically have an unlimited number of 505U modules, but in practice, the number
is limited by the amount of radio traffic on one frequency in the system. When a radio channel
becomes unreliable because of radio traffic , then a second radio channel must be used to increase
the size of the system. This limit is not a function of the number of modules, but the number of radio
messages.
A system comprises 505U and 105U modules - each can transmit input signals. The 105U can
"hear" other radio messages, and will hold off transmitting a message until the radio channel is clear.
The 505U module cannot, and there is a possibility that an individual transmission will clash with
another transmission, and both transmissions will be corrupted. This possibility increases as the
density of transmissions increases. Configuring the re-transmit feature (transmission of each message
several times) will increase the chance of each message being received successfully, but will increase
the overall density of radio traffic.
For large systems, a compromise is required between the number of re-transmissions, and the
update times for each input. High priority inputs should have shorter update times than lower
priority inputs.
The peak transmission density should be calculated for large systems. These values are calculated
by determining the number of transmissions from inputs changing value and the number of update
transmissions per hour.
The probability of success for an individual message depends on the transmission density and the
number of re-transmissions for each message. This is shown in the following graph:
100%
90%
80%
70%
60%
50%
40%
30%
20%
10 %
0%
0 1000 2000 3000
Messages Per Hour
Transmissions
per message
1
2
3
4
5
This assumes that the radio path is reliable and that there is no other radio users on this radio
channel. If intermediate repeaters are used, then each repeated message should be counted as
another message.
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