UL8
Logger Technical Information
 Introduction
The UL8 logger together with the DL4, UL24 and
RL24 form SHM’s
family of advanced data loggers for energy monitoring.
The UL8 is robust, reliable and easy to install. All input
and power connections use 2-part plug-in terminal blocks.
The UL8 has eight universal inputs that can each be configured
to monitor Digital (pulse), Status (on / off), Analog (0 to
10 V or 0 to 20 mA) or Temperature (thermistor) sensors.
Digital and Status inputs accept volt-free relay contacts,
providing direct connection to all the common utility meters
(Electricity, Oil, Gas, Water, Compressed Air, Steam). Analog
inputs can be connected to any sensor whose output is one
of the industry standard levels, 0 to 10 V or 0 to 20 mA.
Temperature inputs are connected to a NTC precision thermistor
sensor.
Each channel in the logger is independent, and can be configured
to log data at intervals of between 1 and 60 minutes, or be
triggered by an external input. When logging every 30 minutes,
each channel logs data for approximately 60 days before wrap-round
occurs.
The logger is mains powered, but can be fitted with a UPS
that allows it to continue logging for up to 5 days without
mains power.
The logger has its own clock / calendar which is used to timestamp
all readings.
The logger is interrogated and controlled via its serial
port. The main serial port on the enclosure is normally used
for local
interrogation by a portable PC. A second internal serial port
can be used to connect to a modem or similar device, and is
used for remote access.
The UL8 can be a stand-alone logger or be connected to other
SHM loggers (of any type) via a simple local area network.
Connection to the host PC can be via direct connection, telephone
modem, RF modem (Paknet) or Ethernet TCP/IP. A variety of
solutions are available to minimize installation and communications
costs.
SHM supplies a simple PC utility to configure the many firmware
options available on the logger. To collect the logged data
another utility
is available to store it in standard CSV format for importing
into spreadsheet programs like Microsoft Excel. If full -featured
energy monitoring is required, then the leading energy information
software package Stark RT is the preferred choice, and comes
with the UL8 protocol built in. SHM is an Approved Application
Partner for Stark Software International and will provide
full details of RT on request.
Protocol
The UL8 uses a proprietary packet-based full duplex protocol,
designed to allow multiple loggers to be connected together
in a variety of network configurations. It provides fast efficient
data transfers and minimizes cost when using a communications
medium with a per packet tariff (eg. Packnet).
· Multi-Level Security
The UL8 logger has 4 levels of security each controlled by
32-bit numeric passwords. Each channel has independent passwords
for reading data and configuration. Internal counts of log-in
failures and password changes are provided to track attempts
at unauthorized access.
For non-critical installations, the security system can be
bypassed by programming null passwords (this is the factory
default).
Time Control
To avoid sudden changes in the time (and consequent discontinuities
in the log), a ‘phase lock’ technique is used
to keep the time on track.
During regular reading, the ‘correct’ time, derived
from an accurate clock in the host computer, is sent to the
logger. The logger compares this to its own time and finely
adjusts the rate of its clock so that any error is corrected.
This is a privileged function and requires knowledge of the
‘time controller’ password.
Channel
Inputs
The UL8 logger has 8 inputs and 8 memory channels, and these
are normally configured to correspond (Memory Channel 1 is
connected to Input 1 etc.). However it is possible to assign
any input to any channel, or to assign one input to two or
more channels.
One use of this feature is to configure an input to connect
it to both a long-term log channel logging at 30 minute intervals,
and a short-term log channel logging every minute.
Logging
Interval
A channel’s logging interval can be changed at any time
without losing the previous stored data.
A channel can also have its logging triggered by an external
time reference connected to one of the logger inputs. This
can be used to log 30-minute electricity readings in synchronism
with the supply tariff meter.
Channel
Size
The available memory can be distributed among the channels
to tailor the channel size to the application.
Channel
Type
Each channel can be configured to log pulse counts, status
(on / off), analog values or temperature. A built-in linearizer
converts the resistance of a 10k thermistor to degrees Celsius.
Data Authentication
All messages containing logged data have a 16-bit validator
appended. This validator provides a checksum for all the data
in the message and guards against data corruption or tampering.
The validator calculation uses a configurable 32-bit authentication
key.
Immediate Data
All channels can be read as immediate (rather than stored)
values, updated every second.
Channel Alarms
The logger can be programmed with simple high and low alarm
thresholds for each channel. The alarm status of each channel
is logged alongside its data. The logger can be programmed
to make selected channel alarms notify the user, either by
activating a relay, or by dialing in to a central point.
Communications
Sharing
There are a number of features for sharing communications
with other users, thus minimizing cost.
The Modem Answer Window feature configures the logger to only
answer the line outside normal office hours. This allows the
line to be shared with an office telephone or fax.
The Dial-In feature configures the logger to dial in once
per day to the Host PC, as opposed to the usual configuration,
where the Host PC dials the logger. This minimizes the inconvenience
to other users of a shared line.
The Modem Serial Switch option allows the logger to share
a modem with another device (eg. tariff meter). The device
automatically switches the data connection to the logger when
interrogated.
Hardware Options
The following hardware options are available to order :
1. RS485 Interface. Used to connect loggers together in a
LAN.
2. LCD Display module. Displays immediate channel readings.
3. Modem Serial Switch. Allows the logger to share an external
modem.
For further information on this product or advice on loggers,
meters, sensors or Energy Monitoring Systems, contact Stark
North America, Inc.
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Introduction
