4
Measuring Loop Current
The 24V Supply includes leads to simplify connection to a DC current meter
for loop current measurements. The current meter leads have safety insulated
banana plugs that can be plugged directly into a standard current meter. An
internal diode allows the meter to be connected or disconnected without inter-
rupting the loop supply or opening the loop. See
Figure 2 Device Connections
for details
.
HART Protocol Modem Connections
A HART modem or HART communicator can be connected to the 24V Supply
loop using the two loop-terminals provided next to the current meter leads. The
loop terminals allow standard HART modem mini-clips to be easily connected
across an internal 250 ohm loop resistor.
MIN MAX
RANGE
REL
Hz %
AutoHOLD
Peak MIN MAX
4½ DIGITS
1 Second
˚
C/
˚
F
OFF
mA
A
mV
V
V
A
A
mA
COM
V
400mA
FUSED
10A MAX
FUSED
A
LO
LO
Connect a milliamp meter
to the shielded banana
jack leads to monitor loop
current.
Removing the current
meter does not open the
loop.
For calibrating HART devices a HART
protocol modem or calibrator can be
attached across the internal 250
Ω
loop
resistor by clipping on as shown.
Connect the red mini-clip to the
transmitter (+) supply terminal.
Connect the black mini-clip
to the transmitter (-) supply
terminal.
Figure 2: Device connections
Milliamp Meter (optional)
Loop Transmitter
