©
2017 Sensata Technologies
Page 40
Installation
2.9 Wiring the Auxiliary Relay
The PT controller contains an internal auxiliary (aux) relay used to turn an external DC device
on or off. The aux relay is wired through an on-board 3-port connector (see Figure 1-2, Item 7).
When the PT controller is con
fi
gured as a standalone controller, this aux relay only engages when
there is a controller fault.
When the PT-100 is networked to a Magnum inverter and using a Version 4.0 remote (ME-ARC
or ME-ARTR), this relay can indicate when a PT controller fault has occurred or be programmed
to automatically engage or disengage based on high or low battery voltage. For example, this
relay can be used to drive a relay for DC load control, or to turn on devices such as a battery
compartment vent fan or a DC indicator light (see Figure 2-20). For more information on the relay
operation, refer to Section 4.10.
Auxiliary Relay Information
• The relay is a single-pole, double-throw (SPDT) relay provided with the NC (Normally Closed),
COM (common), and NO (Normally Open) contacts (see Figure 2-20).
• Any voltage connected to the relay must be less than or equal to the relay’s contact ratings
(Contact Ratings: up to 30 VDC @ 5 amps, and above 30 VDC up to 100 VDC @ 0.5 amp).
• Disengages/opens if power to the PT controller is lost.
• Provides “dry contact” connections (it does not provide any voltage or current); so for any
external device that requires voltage or current, it must be provided externally and routed
through the relay. This relay is not intended to directly provide power. Rather, this relay can
be used to send a signal to operate the coil of another higher amperage device that does the
actual switching of power.
• An in-line fuse rated up to 5 amps (up to 30 VDC) or 0.5 amp (above 30 VDC to 100 VDC)
must be used to protect all power circuits connected to the aux relay (do not fuse ground
connections). The fuse should be located as close as possible to the power source. A fuse must
be used, even if the circuit is providing only a “dry contact” or “ground” connection—it will
prevent damage if the connection is miswired or damaged. Ensure the fuse is correctly rated
for the wire size used. Refer to national and local codes for fuse rating and type. Be aware that
damage to the relay is not covered under warranty.
• The aux relay circuit is not rated for AC volts and may cause damage if connected/used.
Terminal Block Information
• The aux relay is wired through an Euro-style connector (see Figure 1-2, Item 7).
• The connector provides a three-port slotted screw-type terminal block for wiring—requiring a
#2-3 slotted screwdriver (9/64 or 3.5 mm tip width).
• Each port on the terminal block accepts a single wire from #26 to 12 AWG (0.13 to 3.3 mm²).
Figure 2-20, Auxiliary Relay Connections and Example
NO
COM
NC
I
NSIDE
THE
PT
:
AUX
RELAY
&
TERMINAL
BLOCK
(
DISENGAGED
)
E
XTERNAL
DC P
OWER
S
OURCE
NO
COM
NC
I
NSIDE
THE
PT
:
AUX
RELAY
&
TERMINAL
BLOCK
(
ENGAGED
)
A
UX
R
ELAY
C
ONNECTIONS
- E
XAMPLE
A
UX
R
ELAY
T
ERMINAL
B
LOCK
C
ONNECTIONS
N.
O.
N.
C.
CO
M
FU
SE
FU
SE
E
XTERNAL
DC P
OWER
S
OURCE
