Samson 3730 Series Mounting And Operating Instructions page 43

Connections
as for positioner connected in hazardous ar-
eas, see Fig. 17).
250 Ω
If the positioner is used in hazardous areas,
22 μF
an explosion-protected isolation amplifier is
to be used.
Controller/control station
By means of the HART protocol, all control
room and field devices connected in the
loop are individually accessible through
their address via point-to-point or standard
Fig. 18 · Adapting the output signal
bus (Multidrop).
Point-to-point:
The bus address/polling address must al-
ways be set to zero (0).
Standard bus (Multidrop):
In the standard bus (Multidrop) mode, the
positioner follows the analog current signal
(reference variable) as for point-to-point
communication. This operating mode is, for
example, suitable for split-range operation
of positioners (series connection). The bus
address/polling address has to be within a
range of 1 to 15.
Note:
Communication errors may occur when the
process controller/control station output is
not HART-compatible.
For adaptation, the Z box (order no.
1170-2374) can be installed between out-
put and communication interface.
At the Z box a voltage of 330 mV is re-
leased (16.5 Ω at 20 mA).
Alternatively, a 250-Ω resistor can be con-
nected in series and a 22-μF capacitor can
be connected in parallel to the analog out-
put. Note that in this case, the controller out-
put load will increase.
43
EB 8384-3 EN