MACTek BULLET™ – User Manual
DM1101010UAB
Copyright 2009-2010
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WirelessHART is a mesh network – each node in the network will route messages on
behalf of other nodes in the network. This is done to expand the overall range of the
network and also for the data reliability of the network by forming multiple redundant
paths. By setting the Bullet to a high StepVolt™ setting, more WirelessHART packets
can be routed through the Bullet for other nodes in the network.
Another consideration from a WirelessHART network standpoint is that many devices in
a WirelessHART network are battery powered and all wireless transmissions performed
by these devices impact their battery life. The more WirelessHART devices that a
battery powered node has to route messages for, the shorter its overall battery life is.
The Bullet is different – since it is loop powered it can support wireless messages
indefinitely without any concerns of battery life. By placing MACTek Bullet’s at key
locations in a WirelessHART network, such as places that route messages for other
WirelessHART nodes, this routing function can be offloaded from battery powered nodes
to the Bullet and help to preserve their battery life of the battery powered nodes.
StepVolt Setting
WirelessHART Packets per Second
1.0 V
5.79
1.5 V
12.65
2.0V 19.66
2.5V 26.66
Note: The value shown in WirelessHART Packets per second column is the value
reported back in HART Command 777. These values are preliminary and subject to
change.
Recommendation: Plan on using the highest StepVolt™ setting possible to help the
overall WirelessHART network performance.
Direct Powered Mode
In direct powered mode, the Bullet can be powered by an external DC supply.
The DIRECT POWER connections are DIRECT POWER, black lead wire, to the positive
potential and the RETURN, white lead wire, to the negative terminal of the external DC
source. The voltage range of this input is 7VDC to 32VDC.
External Power Source Mode
The Bullet can be powered by an external DC power source such as; battery, solar panel
and control power to the Field device.
