BusWorks®
961/962PB Module User’s Manual ProfiBus Differential I/V Input
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Acromag, Inc. Tel:248-624-1541 Fax:248-624-9234 Email:
http://www.acromag.com
8
on
R
off
In
s
u
l
A
on
OUT
R
off
CABLE
SHIELD
CABLE
SHIELD
INP
GROUND
CLAMP
B
G
rn
PROFIBUS
CONNECTOR
GROUNDING:
ACROMAG MODULES:
THE SHIELD IS COMMON TO
THE HOUSING (FOR METAL
ENCLOSURES).
EARTH GROUND SCREW
ON EQUIPMENT (WHEN
AVAILABLE)
PROFIBUS FIELD DEVICE
EQUIPOTENTIAL BONDING STRIP
(IF NECESSARY--SEE NOTE)
Green Wire = A
Red Wire = B
Use ProfiBus cable
per DIN 19245 and
EN 50170.
PVC
Sheath
R
e
d
GROUND
CLAMP
Use only approved cables
with braided shields of
density greater than 80%.
PROFIBUS
CONNECTOR
S
h
ld
PROFIBUS CABLE
THE SHIELD IS COMMON TO
THE HOUSING (FOR METAL
ENCLOSURES).
PROFIBUS FIELD DEVICE
PROFIBUS WIRING AND GROUND
NOTE: If a potential difference exists between
earth grounding points, an equalization current
can flow through the cable shield when connected
at both ends. In this case, it may be necessary to
install an additional potential equalization line between
field locations to minimize this current as shown here.
The metal shroud of the DB9 ProfiBus connector on
Acromag modules is common to pin 1 of the DB9
connector (SHIELD). This is also common to the
cable shield which must be earth grounded. Acromag
modules are enclosed in plastic and do not
provide a dedicated earth ground screw. As such,
a local earth ground connection to the cable shield
must be made as shown above.
EARTH GROUND SCREW
ON EQUIPMENT (WHEN
AVAILABLE)
1. Always connect the cable shield to earth ground at both
ends as shown.
2. If the field device does not include an earth ground
screw, it may be necessary to strip the cable insulation
near the field device and clamp the cable shield to a local
grounding bar or surface as shown.
Connect Earth Ground as shown in the connection drawings above.
Additionally, ground the ProfiBus cable as shown in the drawing below.
The ground connections noted are recommended for best results. If
sensors are already grounded, use caution and avoid making additional
ground connections which could create ground loops.
The plastic module housing does not require earth ground.
The module routinely performs internal diagnostics following power-up
or reset. During this period, the gr
een “Run” LED will flash for a moment. If
the diagnostics complete OK, the “Run” LED will stop flashing after a few
seconds and remain ON. This indicates the unit is operating normally.
Once the unit has passed through the initialization, parameterization, and
configuration states, and is in data exchange mode, the yellow BUS LED will
be ON. If the BUS LED is OFF and the unit is connected to the network,
then this may be indicative of an initialization problem (check the address
setting).
Follow the ProfiBus installation guidelines.
Use the recommended cable and connectors of the standard.
Verify that none of the wires are broken or shorted.
Don’t mix the A & B lines. Use green wire for A and red wire for B.
Do not exceed the recommended segment length for the baud rate.
Make sure that there are no more than 32 RS-485 devices per
segment (including the master device and the repeater).
Check for proper termination of all copper-wire network segments
(an RS-485 segment must have a termination resistor at both ends
of the segment only).
Earth Ground
Warning:
To comply with
safety and performance
standards, use shielded cable
and connect earth ground as
noted. Failure to use good
wiring and grounding practices
may be unsafe and hurt
performance.
TROUBLE-
SHOOTING
Tips For Building
ProfiBus Networks
