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6
Switching
Switching variants of the SS9007 Mini CT Meter can be used to switch loads of arbitrary size
indirectly using an inbuilt 5A 240VAC latching relay. If your device is marked with an R on its variant
label (e.g. “120A/
R
”
), the two terminals marked 'SWITCH' are connected internally to an isolated
relay.
The internal relay would typically be used to control a third party external contactor or to signal a
control system. Because the relay contacts are isolated, the SS9007 Mini CT Meter can be connected
directly to a digital IO on a control device such as a PLC.
The example below shows a SS9007 Mini CT Meter being used to control an external contactor with
a 240V coil by switching the active input t
o the contactor’s control
coil.
Figure 4: External contactor wired to SS9007 Mini CT Meter
The internal relay in the SS9007 Mini CT Meter is rated for over 20000 switching operations of a 5A
load at unity power factor. The relay is limited to one switch state transition per second (e.g. the
device cannot be switched on and off at a rate faster than 0.5Hz).
A value of 1 in the ‘Switch State’ attribute of the On/Off Cluster indicates that the relay is closed
(connected), and a value of 0 indicates that the relay is open (disconnected).
