Advanced Power technologies TTC-1000, Инструкция по эксплуатации, Страница: 40 / 262

V6.230 20131017
29
3.9 Heater Connections
NEMA 4X Models, TTC-1000-4XX, are equipped with a 13 Watt thermostatically
controlled heater and a specially designed vent that allows moisture to escape
and does not allow moisture to re-enter. The heater can be operated from DC
voltages of 38 to 160 or at 120 VAC. For convenience, the heater circuit is
connected to TB3 terminals 1 and 2. However, the user can connect the heater
to a separate power source.
The thermostat turns off the heater circuit when the internal ambient temperature
rises above 86

F (30

C) +/-10

F. The thermostat turns the heater back on at an
internal ambient temperature between 80 to 75

F.
3.10 Shield Drain Wire Grounding
Shielded wire must be used for all CT and probe inputs. The shield drain wire of
the CTs and probes MUST be grounded on one of the studs on the back panel of
the panel mount unit, or the interior stud of the NEMA 4 enclosure on the TTC-
1000. Failure to ground the shield drain wires may cause reading errors, false
alarms, and/or possible unit damage. For units equipped with analog outputs and
RS-485, is recommended that the cables’ shield drain wires for those
connections are grounded to either one of the studs of the back panel of the
panel mount, or the interior stud of the NEMA 4 enclosure on the TTC-1000.
Failure to ground the shield drain wire on the TTC-1000 end may cause reading
errors and possible unit damage.
In the event that the shields of the analog outputs and/or the RS-485 are
grounded on the opposite end of the TTC-1000, there are alternative connection
methods available to provide stable unit operation. One method is connecting a
single 0.47 µF 300V capacitor between each shield drain wire and one of the
studs of the back panel of the panel mount unit, or the interior stud of the NEMA
4 enclosure on the TTC-1000. Another method is to connect one 1.0 µF 300V
rated capacitor for every two shielded cable’s drain wire between the two shield
drain wires and one of the studs of the back panel of the panel mount unit, or the
interior stud of the NEMA 4 enclosure on the TTC-1000.
Advanced Power Technologies has a capacitor kit available, part number
8AOMKIT0000, that contains one 1.0 µF 300V rated capacitor.