Yamatake Corporation
4-26
ST3000 Smart Transmitter Series 900 Electronic Differential Pressure/Pressure Transmitter
4-4-3 :Wiring Transmitter -- Intrinsically-safe
Guidelines
Intrinsically safe requires special wiring precautions and installation methods. Refer to
"4-4-1 :Wiring for Transmitter -- Regular Model".
WARNING
• Protect transmitter from electrical or magnetic influence (such as mixing
and induction) from other electrical circuits.
• Use a Zener barrier approved by an approval body such as FM and
NEPSI.
Wiring
• Follow the instructions in the installation drawing (80390790) for FM
intrinsically safe loops.
• In case of NEPSI, combine with a NEPSI approved Zener barrier;
Z787,MTL787S or LB987S.
Following parameters must be taken.
Maximum allowed cable capacitance = 0.1
µ
F
Maximum allowed cable inductance = 2mH
See instruction manual of Zener barrier.
Intrinsically-safe system - Configuration
System configuration
The system configuration is shown below. The diagram also shows the layout of an
intrinsically-safe system consisting of a transmitter, a portable setting display, a field
type current indicator, and a Zener barrier. The system components must be desig-
nated as having conformance that is proved by relevant public organizations.