Technical information
12 © 2010 Schneider Electric. All rights reserved. F-26266-7
Power Supply Wiring
Caution:
• MicroNet I/A Series Controllers are Class 2 only devices and must be connected to a
Class 2 source. Class 2 circuits must not intermix with Class 1 circuits.
• This product contains a non-isolated half-wave rectifier power supply and must not be
powered by transformers used to power other devices containing non-isolated full-wave
rectifier power supplies. Refer to EN-206, Guidelines for Powering Multiple Devices
from a Common Transformer, F-26363, for detailed information.
• Power wiring cannot be intermixed with LON, S-Link, UI, AO, or DI wiring.
• Use a Class 2 power transformer supplying a nominal 24 Vac (20.4 to 30 Vac) with a
minimum rating of 15 VA at 50/60 Hz plus digital output loads (144VA using 6 DOs or
96VA using 4 DOs if same transformer is used). The supply to the transformer must be
provided with a breaker or disconnect. In European Community, transformer must
conform to EN 60742.
• The Class 2 power transformer may be used to power multiple Class 2 powered devices
provided that the transformer is properly sized to power all equipment simultaneously
and all devices contain the same type of rectifier power supplies or internal isolation.
• The transformer frame must be grounded.
• When powering multiple Class 2 devices from the same Class 2 power transformer,
polarity must be observed (24H connected to 24H and 24G connected to 24G).
Note:
• Power wiring terminals accept one 16 gage (1.29mm) or two 18 gage (1.02mm) wires.
• Power wiring can be intermixed with DO wiring.
• Twisted or untwisted cable can be used for power wiring.
• To preserve the integrity of the network, the LON wiring connecting a TAC I/A Series
MicroNet controller to an MN-Sx sensor must be run to the sensor and back, in daisy-
chain fashion. A wire “spur” must not be used to connect the sensor to the controller.
Figure-8 and Figure-9 are acceptable wiring configurations.
Figure-8 Single Controller Powered from a Separate Class 2 Power Source.
Ground Frame
of Transformer
to Known Ground
Primary 24 Vac
Secondary
Class 2
MNL-10Rxx
MNL-15Rxx
MNL-20Rxx
MN-Sx
Sensor
S-Link
1
Optional connection
provides local access
to the L
ONWORKS network.
1
To rest of the LONWORKS
network.
LON
Observe Free or Daisy chain topology when making connection to rest of network.