<3. Getting Started>
3-1
IM 12A01A02-72E
3rd Edition : Oct. 01, 2015-00
3.
Getting Started
PROFIBUS PA is fully dependent upon digital communication protocol (EN 50170 Volume 2 and
IEC 61158 for IS areas, PROFIBUS PA) and differs in operation from the conventional 4 to 20
mA transmission communication protocol. It is recommended that novice users use field devices
in accordance with the procedures described in this section. The procedures assume that field
devices will be set up on a bench or an instrument shop.
3.1
Connection of Devices
The following instruments are required for use with PROFIBUS PA devices:
• Power supply:
PROFIBUS PA requires a dedicated power supply. It is recommended that current capacity
be well over the total value of the maximum current consumed by all devices. Power is
supplied by a DP/PA coupler.
• Terminators:
PROFIBUS PA requires two terminators. A terminator shall be located at each end of the
trunk cable.
• Field devices:
Connect the PROFIBUS PA communication type field device. Two or more transmitters or
other field devices can be connected.
• DP/PA Couplers:
PROFIBUS PA requires DP/PA couplers which convert the RS-485 signals to the IEC
61158-2 signal level and power the field devices via the PROFIBUS PA.
• Cable:
Refer to Table 2.2.
For applications in intrinsically safe areas, the transmission method defined in IEC 61158-2 is
used with PROFIUS PA The transmission rate in this case is 31.25 k bit/s. DP transmission via
RS-485 to IEC 61158-2 is implemented with the network components (DP/PA coupler or DP/PA
link.)
Connect the devices as shown in Figure 3.1. Connect the terminators at both ends of the trunk,
with a minimum length of the spur laid for connection.
The polarity of signal and power must be maintained.
FLXA21
Power
supply
Terminator
HOST
Coupler/terminator
Figure 3.1
Cabling