Omron B7A Manual page 107

B7A
Precautions
Note: The undermentioned is common for all B7A-series Link Terminals.
General
Each terminal of the B7A-series should be used for only single sig-
nal transmission without a transmission host. The B7A-series can-
not be connected to OMRON's SYSMAC BUS Remote I/O System.
Avoid places subject to corrosive gasses or continual shock and/or
vibration.
If high-level electrostatic discharge is generated at the installation
site (e.g., for transfer of a molding material, powder, or liquid through
a pipe), separate the Link Terminals as far as possible from the
source of the electrostatic discharge.
If the Input and Output Terminals are connected via a three-conduc-
tor cable to transmit signals with a single power supply (i.e., the
power supply is connected directly to one of the Link Terminals and
indirectly to the other), the transmission distance greatly varies with
the diameter of the cable. This is due to the potential difference be-
tween the current on the 0-V transmission wire and on the 0-V I/O
transmission line caused by the resistance of the cable. By increas-
ing the diameter of the cable (decreasing its resistance), the trans-
mission distance can be increased. By reducing the resistance of
the transmission path to 2.5 Ω or less for example (i.e., increasing
the thickness of the wire to 1.25 mm
tance of 160 m will be achieved.
It is recommended that a switch for minute loads be connected to
the 16-point screw terminal model because there is a contact input
current of only 3 to 6 mA to the model from the connected switch or
relay.
The Output Terminal has an error of 300 ms maximum after the Out-
put Terminal is turned on. The user should be well aware of this be-
fore using error outputs.
Note: The 10-point and 16-point models cannot be connected to
each other because their transmission signal data formats
are not compatible.
Screw Terminal Models
Apply a torque of 0.78 to 1.18 N m to tighten wiring terminals.
Hold both edges of the terminal cover to open it.
If the Input or Output Terminal is mounted to a panel with screws,
apply a torque of 0.59 to 0.98 N m to tighten the screws.
2
or more), a transmission dis-
Modular Models
Soldering (with an soldering iron or in a soldering tab) must be com-
pleted within 5 s at a temperature of 260 C or less.
The supply voltage must be within the operating voltage range. Do
not use a power supply which generates irregular voltages or large
ripples.
Do not apply a strong acidic or alkaline solvent to the printed circuit
board for removal of the flux. The module of the B7A 10-point model
is not of closed-mold construction. The solvent must not remain on
the bottom of the module after the module is cleaned. The module of
the B7A 16-point model is of closed-mold construction.
The input and output circuits are not insulated. If Link Terminals are
influenced by external noise, use photocouplers to insulate the I/O
circuits.
Terminals with PLC Connector Models
Apply a torque of 0.78 to 1.18 N m to tighten wiring terminals.
Be sure to disconnect the connector unit from the PLC's I/O connec-
tor unit when wiring the screw terminals in order not to impose ex-
cessive force on the PLC's I/O connector unit.
Use the B7A in combination with a PLC correctly, otherwise the B7A
may be damaged. The following are correct combinations.
B7A Input Unit and PLC Output Unit
B7A Output Unit and PLC Input Unit
Wiring
Separate the transmission lines from high voltage or power lines as
far away as possible and do not wire the transmission lines in paral-
lel with high voltage or power lines. If Link Terminals are used near a
device that generates noise, make sure that the Link Terminals do
not malfunction due to the noise generated from the device.
Make sure to turn off the Link Terminals while wiring in order to avoid
a short-circuiting accident that may damage the internal element(s)
of the Link Terminals.
Link Terminals will malfunction if the SIG terminal is short-circuited
with one of the power terminals or Bjj terminal. Before turning the
power on, make sure that the SIG terminal is not short-circuited with
these terminals.
Before checking the insulation resistance of the transmission path,
disconnect the wires from the Link Terminals.
If the OUT terminal and positive power terminal of the Output Link
Terminal is short-circuited during signal transmission, the Link Ter-
minal will malfunction. Apply an appropriate load between these ter-
minals.
When measuring the current, use a multimeter without disconnect-
ing the load.
B7A
105