Yokogawa EJA115 - Manual (Page 16)

IM 01C22T03-00E 4-1
4. GETTING STARTED
4. GETTING STARTED
PROFIBUS PA is fully dependent upon digital
communication protocol and differs in operation from
conventional 4 to 20 mA transmission and the BRAIN
communication protocol.
HMI
Class I Master
I/O CARD, PLC, etc.
PROFIBUS-DP
PROFIBUS-DP devices
PROFIBUS-PA devices (EJA)
PROFIBUS-PA (31.25 kbps)
Class 2 Master
FieldMate (FDT/DTM)
PDM (EDDL), etc.
DP/PA
Coupler
F0401.EPS
Figure 4.1 Profibus System Construction
4.1 Connection of Devices
The following 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.
Two or more EJA devices or other 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 Figure 4.1.
Table 4.1 PROFIBUS PA Cables and Transmissible Length
Type A: Individually-shielded
twisted pair cable
Type of cable
#18AWG
(0.82 mm 2 )
Cable
specifications
1,900 m
Max. length of
cable
(reference value)
1,200 m
400 m
200 m
#22AWG
(0.32 mm 2 )
#26AWG
(0.13 mm 2 )
#16AWG
(1.25 mm 2 )
Type B: Overall-shielded
twisted pair cable
Type C: Unshielded twisted
pair cable
Type D: Overall-shielded
non-twisted cable
T0401.EPS
Note: Yokogawa recommends the use of Type A.
Usage of Type B and D is restricted.
Yokogawa does not recommend the use of
Type C.