29
Circuits and Devices
7.0 Circuits and Devices
7.1 Addressable/Analog Devices
The FX-350 supports up to 3 loops of addressable/analog devices. The device loop can be
used to connect up to 60, 126 or 378 analog devices and addressable input or output modules
on an unshielded twisted pair (UTP). The devices must be compatible with the Mircom device
protocol.
The loop interface software continuously supervises the devices on its loop against those
found during configuration for the following conditions:
• device missing
• unconfigured device responding
• two or more devices responding to the same address
• wrong device type
A communication or addressing error on a device is reported as a trouble on the associated
zone LED if configured.
The addressable loop can be configured for class A or B operation. "T-tapping" is allowed
(Refer to device installation documentation for details).
Devices on the loop have an optional LED which normally flashes when the device is polled
and goes ON steady when the device is active (alarm for an input device or active for an
output device). The flashing of the LED on polling for sensors can be suppressed during
configuration. For input or output modules, the LED always flashes when polling. The software
limits the maximum number of the devices which can have their LED turned ON when active to
fifteen (15).
Certain devices are designed to support an optional external LED, which operates when the
LED on the device is activated. Remote/external LEDs must NOT be used on this system. The
panel can provide up to 350mA of current to the devices on the loop. A maximum line loss of 5
volts is permitted, so the loop distance, wire size, and maximum number of devices are limited
by this constraint.
The devices should be installed using unshielded twisted pair (UTP). The total line drop on the
loop must not exceed 5 volts at the last device. The calculations required to determine the
maximum permissible loop wiring distance with various combinations of devices is relatively
complicated, and when isolators are used, includes a consideration of device inrush currents
which must not exceed 20mA for a single isolator. In no case should more that twenty devices
be connected to a single isolator. To simplify the calculation process, please utilize the loop
calculator program located on the Mircom website at http:/www.mircom.com
in order to
determine maximum loop lengths, number of devices, and wire sizes etc.
It is also important to note that the device LEDs present a significant extra load on the loop
which must be considered in calculating permissible loop lengths, battery capacities, etc.
Please refer to the device Installation Instructions and other documentation provided with the
addressable devices, bases, and isolators for further information. The system will
automatically limit the maximum number of device LEDs which can be illuminated to
15.
To Next Page
Loading...
Need help?
General
