Marathon Computer AACC 2000 - Manual (Page 7)

Marathon Monitors Inc.
AACC 2000 Carbon Nov. 1, 1997
7
Where damage or injury is possible, we recommend fitting a separate over-temperature
protection unit, with an independent temperature sensor, which will isolate the heating
circuit.
Please note that the alarm relays within the controller will not give protection under all
failure conditions.
Grounding of the temperature sensor shield
In some installations it is common practice to replace the temperature sensor while the
controller is still powered up. Under these conditions, as additional protection against
electric shock, we recommend that the shield of the temperature sensor is grounded. Do not
rely on grounding through the framework of the machine.
Installation requirements for EMC
To ensure compliance with the European EMC directive certain installation precautions are
necessary as follows:
•
For general guidance refer to MMI Controls EMC Installation Guide, HA025464.
•
When using relay or triac outputs it may be necessary to fit a filter suitable for
suppressing the emissions. The filter requirements will depend on the type of load. For
typical applications we recommend Schaffner FN321 or FN612.
•
If the unit is used in table top equipment which is plugged into a standard power socket,
then it is likely that compliance to the commercial and light industrial emissions
standard is required. In this case to meet the conducted emissions requirement, a
suitable mains filter should be installed. We recommend Schaffner types FN321 and
FN612.
Routing of wires
To minimise the pick-up of electrical noise, the wiring for low voltage dc and particularly
the sensor input should be routed away from high-current power cables. Where it is
impractical to do this, use shielded cables with the shield grounded at both ends.