15
Caution:
Live sensors
The controller is designed to operate if the
temperature sensor is connected directly to an
electrical heating element. However, you must
ensure that service personnel do not touch
connections to these inputs while they are live.
With a live sensor, all cables, connectors and
switches for connecting the sensor must be mains
rated for use in 240Vac CAT II.
Wiring
It is important to connect the controller in
accordance with the wiring data given in this guide.
Take particular care not to connect AC supplies to
the low voltage sensor input or other low level
inputs and outputs. Only use copper conductors for
connections (except thermocouple inputs) and
ensure that the wiring of installations comply with
all local wiring regulations. For example in the UK
use the latest version of the IEE wiring regulations,
(BS7671). In the USA use NEC Class 1 wiring
methods.
Power Isolation
T
he installation must include a power isolating
switch or circuit breaker. This device should be in
close proximity to the controller, within easy reach
of the operator and marked as the disconnecting
device for the instrument
.
Overcurrent protection
The power supply to the system should be fused
appropriately to protect the cabling to the units.
Voltage rating
The maximum continuous voltage applied between
any of the following terminals must not exceed
240Vac:
•
relay output to logic, dc or sensor
connections;
•
any connection to ground.
The controller must not be wired to a three phase
supply with an unearthed star connection. Under
fault conditions such a supply could rise above
240Vac with respect to ground and the product
would not be safe.
