DXcalibar® Field Monitoring Automatic Calibration and Barrier Box (Product 4.512x)Contact Sales(Hover over the image to enlarge) The DXcalibar ® is a compact, integrated, field monitoring and communication box that replaces the familiar, but burdensome multi-box alternative. Developed especially for managing large numbers of sensors throughout extensive buildings and facilities, this innovative product saves serious time and money, while improving performance, reliability and visibility. For monitoring large numbers of gas sensors in close arrangements, the usual number of supporting electronics enclosures can occupy an inordinate amount of wall space, requiring expensive conduit, cable and electrician labor to interconnect. By eliminating this octopus of boxes, the DXcalibar® can cut installation and wiring cost by 75% or more. The name "DXcalibar" signifies the DX-bus long distance data communications, the automatic calibration and regulator modules, and the intrinsic safety barriers that are all included in this remarkably compact and modular design. The DXcalibar® can also house an AC/DC power supply with attending backup batteries. Relays for controlling alarms and plant functions such as fans, doors, louvers, shunt breakers and the like are standard. A strobe and horn can be added, as well as palm switches for emergency stop and alarm reset. The overall monitoring system can include 60 or more of these DXcalibar panels, covering up to a 960 hazardous area sensors. Rel-Tek owns a US patent on this product. DXcalibar® Features:
The DXcalibar®
provides an efficient, economical packaging method to quickly and easily install
and manage large arrays of sensors. All essential functions are integrated into
a single box, 16 sensors at a time.
To eliminate the 16 sets of cables
that would otherwise be required to transfer 16 sensor signals back to a central
alarm monitoring point, high speed digital telemetry is included, which multiplexes
all signals onto a single twisted pair communication bus. The DX-bus is Rel-Tek's
long distance communication mode which has been time tested for reliability
and speed in underground mines that extend to 20 miles or more.
The brains in the DXcalibar®
reside in the four DX4404 cards, microprocessor based modules which handle
the communications and I/O. Each card is capable of monitoring four analog (4-20ma)
inputs and four digital contact closure inputs, while controlling four digital
(on/off) outputs, all orchestrated through the central computer facility, possibly
sited in another building or even miles away. Analog resolution is a high precision
12-bit format, cutting the digitizing error to an infinitesimal .024%.
DXcalibar ®
units require communications with a Rel-Tek EZ-Trol/DX computer. Telemetry is
via the DX-bus over a single twisted pair of wires at selectable rates -- even
as high as 115.2k baud. The proprietary DX-bus and attending protocols have
been perfected for long distance and high reliability in noisy environments
and includes advance error detection and correction features. The system can
be expanded to include as many as 63 DXcalibar® boxes (63x16=1008 sensors).
16 sensor inputs per box
is standard, each being a 4-20mA generic analog format. Sixteen dual-channel
I.S. barriers are included, one barrier for each sensor. Power is delivered
to a sensor through one channel of the barrier and the signal is returned through
the second channel. The predominant sensor types used with DXcalibar ®
unit are the GasBoss*100 and the GasBoss*100/AP (outdoor and indoor
versions), each capable of detecting combustible gases with a range of 0-100%
LEL. Both are approved to UL-913, Class I, Div 1 and 2, Group D. Note that Group
D includes methane, natural gas, propane, butane, gasoline, diesel fuel, naphtha,
alcohol and a host of other flammability fuels. Also, available are the GasBoss* 100-C
and the GasBoss* 100/AP-C these newly approved combustible sensors add Group B and C to the
mix allowing gas detection in hydrogen locations. They are US and Canadian approved.
16 dual-channel intrinsic safety barriers
are included for directly connecting to the sensors sited in hazardous areas.
Barriers are also approved to UL-913, Class 1, Div 1 and 2, Group D. It should
be noted that I.S. offers lower costs than explosion proof designs, by virtue
of the easier installation, easier maintenance and shock proof voltages. Unlike
with XP equipment, there is never a need to shut the system down for maintenance.
Safety is assured by the low voltage (under 30 VDC) and current, which eliminate
ignition sources. X/P equipment loses its safety classification the instant
a unit is opened for service. NEC-70 even permits simplified wiring, conduit
and seals for I.S. wiring in hazardous areas -- not so for X/P equipment. Along with
the new GasBoss* 100-C and GasBoss* 100/AP-C are the newly approved I.S. Barriers for Class 1,
Div 1, Groups B, C, D. These UL-913 and CSA C22.2 approved barriers allow gas detection in Groups B, C and D
hazardous locations when used approved sensors.
Because I.S. sensors
are powered through approved I.S. barriers, sensors can be serviced -- or even
replaced -- without disabling the entire monitoring system, and without ever
shutting down operations and declassifying the area. Note: DXcalibar
® boxes, including the I.S. barriers, are always installed in fresh
air; only the I.S. sensors and I.S. cables may be installed within classified
areas.
Another important function is
current regulation which assures that each barrier is properly powered and current
limited, thus completely eliminating costly and tedious fuse replacement.
On any sensor alarm event, alarms must
be sounded and control actions taken to increase ventilation fan speed, to open
doors, selectively kill lights and heaters, cut electrical power and the like.
In the old octopus days, relay boxes were used for housing the high current
control contacts. Now, 16 individually controlled relays are standard in the
DXcalibar ®. Relays have gold plated SPDT contacts rated at
24-120 VAC/DC, 5 amp. Also, available are up to six additional high current relays contacts
rated at 24-120V AC/DC., 10 amps. These relay are available as DPDT or 3PDT versions.
Sensors are seldom
sited with easy access. Methane and natural gas sensors are normally installed
in the roof peaks and skylight areas, because methane is lighter than air. Propane,
sensors, are placed low, near the floor and in service pits, because this gas
is heavier than air. Automatic calibration permits each sensor to be calibrated
and adjusted without risking accidents with lifts and ladders. There is also
no need to stop production and move vehicles out of the way to access sensors
directly. On installation, plastic gas supply tubing is installed for delivering
calibration gas to each sensor from a convenient floor level station. The four
4-channel Current Limiter Card circuit boards in the DXcalibar ® box permits each
sensor signal (4-20ma) to be finely adjusted. Test jacks are included on these
Current Limiter Cards for reading out the raw signal from each sensor as well as the
calibrated signal, using a hand held milli-ammeter.
An innovative
computer calibration utility in the Millennia-DX and FT versions of the monitoring software provides
additional speed and simplicity for automating the once tedious sensor calibration.
Sixteen digital inputs
(dry contact closures) are included within the DXcalibar ® for connecting
switches and any other contact switching devices. The DXcalibar ®
is designed to house switches on the front lid, thus avoiding yet another wall
mount box. Note that by using I.S. barriers for electrical access, such simple,
non-incendive switches may be sited in hazardous areas.
Power supply and backup battery
-- Yet another box to be eliminated by DXcalibar ® is the power
supply and battery backup. The DXcalibar ® is powered from 24-28
VDC, drawing typically 4 amps per box, fully loaded. A power supply can be mounted
inside the enclosure. There is also space for two 12V, 4 AH rechargeable batteries,
powering the DXcalibar ®, with normal sensor and alarm loads during
a brownout or power outage.
A distinctive,
raucous horn and a brilliant strobe can be mounted directly on the DXcalibar
®, thus eliminating more octopus components. If desired, additional
alarms can still be sited remotely from the box, powered and controlled in unison
- or individually, as programmed through the computer.
Each four channel,
side-to- side strip of components is independent. A complement of one to four
strips can be included to meet the sensor count at the particular site. Because
strips are identical, just one set of components (DX4404, Current Limiter Card and barrier)
provides spares for all strips, including those in other DXcalibar ®
units throughout the facility.
LEDs show the power and communication
status of each module and sensor. A malfunction is immediately indicated, making
troubleshooting fast and sure.
Barriers are short circuit protected,
such that an external wiring short on a sensor circuit will not damage the attending
barrier. Unlike with competitor's barriers that are frequently damaged on a
short circuit, the high speed current limiters avoid this problem -- and, there
is never a fuses to replace.
For ease of maintenance,
the DX4404 and Current Limiter modules plug together. Replacing any
of the eight modules (4 of each type) is reduced to simply pulling the plugs,
lifting the module off stand-offs, inserting a replacement module and replacing
the plugs -- all without any tools.
There is plenty of access
space inside the DXcalibar ®. Holes are provided for adding extra
I/O cards and utility modules, as may be needed for extra fresh-air monitoring,
custom control functions or to add a communications repeater and optical isolator.
Our designers thought of everything!
The DXcalibar ® is
UL 508 Approved. DXcalibar ® is covered by Rel-Tek's US Patent 6,109,488.
Rel-Tek has engineered the DXcalibar
® -- including all circuit boards, barriers and computer software --
in house, and offers full warranty and service without the delay and expense
of third party suppliers. Contact the factory for assistance in laying out a
system for your particular application.
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