Banner MULTI-BEAM Series User Manual
Page 2
Transient
& DVDT
Suppression
Switching
Regulated
Power Supply
2
1
Load
AC Supply
Voltage
Solid-State
Contact
Switching
Element
Drive
Circuit
A
C
D
+
−
+8 V dc
Common
No Connection B
Signal from
Logic Module
on
off
Power to Logic Module
& Scanner Block
Figure 2. Functional Schematics
L1
L2
V ac
(See specifications)
Load
1
2
2PBA
2PBB
2PBD
Figure 3. Basic Wiring of 2-Wire MULTI-
BEAM
MULTI-BEAM 2-wire sensors wire in series with an appropriate load. This combination, in
turn, wires directly across the ac line. A 2-wire sensor may be connected exactly like a
mechanical limit switch.
The MULTI-BEAM remains powered when the load is "off" by a residual current that flows
through the load. This off-state leakage current is always less than 1 mA. The effect of this
leakage current depends upon the characteristics of the load. The voltage that appears
across the load in the off-state is equal to the leakage current of the sensor multiplied by
the resistance of the load: Voff = 1 mA × Rload.
If this resultant off-state voltage is less than the guaranteed turn-off voltage of the load,
the interface is direct. If the off-state voltage causes the load to stay "on," connect an
artificial load resistor in parallel with the load to lower its effective resistance. Most loads,
including most programmable logic controller (PLC) inputs, will interface to 2-wire sensors
with 1 mA leakage current without needing an artificial load resistor. There is no polarity
requirement. Either wire may connect to terminal #1 and the other to terminal #2.
CAUTION: All three components of a MULTI-BEAM 2-wire sensor
will be destroyed if the load becomes a short circuit.
L1
L2
V ac
(See specifications)
Load
1
2
2PBA
2PBB
2PBD
1
2
2PBA
2PBB
2PBD
Figure 4. 2-Wire MULTI-BEAMs in Parallel
Multiple 2-wire MULTI-BEAMs may be wired together in parallel to a load for OR or NAND
logic functions. When sensors are wired in parallel, the off-state leakage current through
the load is equal to the sum of the leakage currents of the individual sensors.
Consequently, loads with high resistance, like small relays and electronic circuits, may
require artificial load resistors.
Two-wire MULTI-BEAM sensors have a 100 ms power-up delay for protection against false
outputs. When 2-wire MULTI-BEAMs are wired together in parallel, any power block with an
energized output robs all the other power blocks of the current they need to operate. When
the energized output drops, there will be a 0.1 second delay before any other MULTI-BEAM
can energize. As a result, the load may momentarily drop out.
Two-wire MULTI-BEAM sensors cannot wire in series with other 2-wire sensors unless
power block model 2PBR is used. If series connection of 2-wire ac sensors is required,
consider models within the VALU-BEAM or MINI-BEAM families.
MULTI-BEAM 2-Wire AC Power Block Modules
2
www.bannerengineering.com - tel: 763-544-3164
P/N 03508 Rev. A