B7AH
B7AH
71
Precautions
General
Common
Precautions
The
B7AH performs 1-to-1 communications and does not require a
communications master. It cannot be connected to CompoBus/S
transmission
paths from OMRON remote masters.
Do not use the B7AH in locations subject to corrosive gases.
When using the B7AH in locations where a large amount of static
electricity is generated (e.g., molding materials, powder, or fluid
materials
conveyed along pipelines), install the B7AH at least
1 m
away from the source of the static electricity
.
Line Resistance in the T
ransmission Path
If power and signals are transmitted together along 3-core cable,
ensure that the line resistance in the transmission path between
Link
T
erminals is less than 2.5
Ω
. (The same value applies even if
terminal
blocks, connectors, or slip rings are used at points on the
line.)
If the line resistance rises to a value greater than this, the cur
-
rent flowing to 0 V and the line resistance will
cause
a large voltage
drop,
preventing normal
transmission and generating an error
. As a
rough guide, the line resistance with a VCTF cable of thickness
0.75 mm
2
will be 2.5
Ω
per 100 m.
Connection to 10-point B7A Terminals is not possible because
transmission
signals are not compatible.
If
there is a possibility of shocks or vibration, prevent the pins
being
damaged
by securing
the Link T
erminal to the PCB using an (e.g.,
epoxy-based)
adhesive.
Do
not touch the pins. Doing so may cause deformation. In addition,
touching
the pins in an ungrounded state may result in damage to
internal
elements due to static discharge. Use an anti-static mat dur
-
ing
work to ensure that the body is in a grounded state.
Soldering
When
soldering using a soldering iron or a soldering bath, solder in
less than 5 s at a temperature not exceeding 260°C. Do not use
reflow
soldering.
Cleaning
Do
not use highly acidic or highly alkaline
solvents to clean the PCB.
Power
Supply
Be sure to use the specified power supply voltage. Do not use a
power supply that has a large ripple or intermittently generates
abnormal
voltages.
Noise and Miswiring Protection Circuits
If
there is a possibility of noise interference between the power sup
-
ply
pins (+V and –V or VDD and VSS) or at input or output pins (IN00
to
IN15 or OUT00 to OUT15), or if there is a possibility of miswiring
the
signal pin (SIG) and the positive power supply pin (+V or VDD),
include
the protection circuits described on page
68.
Wiring
Do
not wire transmission lines parallel to, and less than 10 cm away
from,
lines carrying
high voltages or currents. If transmission lines
are
installed less than 10 cm away from potential sources of noise,
confirm
that correct operation is possible before using
the Link T
er-
minal
in actual operation.
Do not perform wiring with the power supply turned ON. Doing so
may
cause pins to be
accidentally short-circuited, resulting in dam
-
age
to internal elements and communications failure.
If
the SIG pin and the positive power supply pin or the VDD (+5 V)
pin
are shorted during communications,
the Link T
erminal will mal
-
function
and normal communications will not be possible. Confirm
that power lines are not shorted before turning ON the power
.
Be
sure to apply the specified power supply to the power supply pins
(positive, negative, VDD, and VSS). Applying excessive voltages
(e.g.,
100 V
AC) will cause the Link T
erminal to malfunction and nor
-
mal
communications will not be possible.
Shorting
(no-load state) the OUT pins
of Output Link T
erminals dur
-
ing
communications will cause the Link T
erminal to malfunction. Be
sure
to connect a load within the
specified load current range. When
measuring
the current with a tester
,
measure with the load supplied.
Recommended Cables
Normal-speed Models
Cabtire
Cables
With
a single power supply connected to Input or Output Link T
ermi-
nal:
0.75-mm
2
VCTF cable
×
3
With independent power supplies connected:
0.75-mm
2
VCTF cable
×
2
The following cables can also be used:
T
wisted-pair Cables
(If only a single power supply is used, a conductor of thickness
0.75-mm
2
min. is required.)
T
ransmission distance: 100 m max.
High-speed Models
Shielded
Cables
Use
cables for which the cross-sectional area of the conductor is
at
least
0.75 mm
2
.
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