Honeywell SmartLine ST 700 - Page 161

Revision 12 ST 700 SmartLine Pressure Transmitters User’s Manual Page 145
Transmitter loop parameters are as follows:
R
LOOP MAX
= maximum loop resistance (barriers plus wiring) that will allow proper transmitter
operation and is calculated as R
LOOP MAX
= (V
SUPPLY MIN
– V
XMTR MIN
)  21.8mA.
In this calculation:
V
XMTR MIN
= 10.8V + V
LP
+ V
SM
V
LP
= 0V for Honeywell supplied lightning protection option, LP
V
SM
= 2.3V, remote meter
Note that V
SM
should only be considered if a remote meter will be connected to the transmitter.
The positive and negative loop wires are connected to the positive (+) and negative (–) terminals on
the terminal block in the transmitter electronics housing.
Barriers can be installed per Honeywell’s instructions for transmitters to be used in intrinsically safe
applications.