3
24V Supply Block Diagram
Figure 1: Block Diagram
REVERSE BA
T
T
ER
Y
PR
OT
EC
T
ION
3 X "AAA" BA
T
T
ER
Y
DC-DC CONVERTER
BATTERY
MONITOR
HIGH EFFICIENCY
FILTER
24 VOLT
TRANSMITTER POWER
SUPPLY LEADS
MILLIAMP METER
TEST LEADS
HART PROTOCOL
MODEM CONNECTIONS
CONTROLLER
CURRENT
MONITOR
STATUS LED
CONNECT / OFF
BUTTON
250
Ω
Connecting to a Loop Device
The Field Tools 24V Supply is a fully contained power source for loop powered
transmitters. Internal batteries eliminate the need for external connections to
AC power or USB ports as a power source while providing complete galvanic
isolation.
Connect the red clip to power or loop (+) and the black lead to power or loop (-)
on your transmitter. See
Figure 2 Device Connections
for details
.
The transmitter
can be powered with or without the milliamp meter connected. The power loop
is not opened when the meter is removed or not attached.
With the 24V Supply clips attached to the transmitter, press the 24V Supply con-
nect button to enable power to the transmitter. The status LED will be ON while
the 24V Supply output is active. If the LED is not ON solid while active, refer
to
Status LED Operation
in this manual.
To remove power from the transmitter press the connect button. The LED will
be OFF while the 24V Supply output is inactive.
The 24V Supply includes a 250 ohm loop resistor that will drop a portion of
the available 24 volts. The voltage dropped across the resistor depends on the
current requirements for the loop transmitter. Open circuit voltage, with no
transmitter attached, is 24 volts +/- 2%.
