Flowserve TRS5-7 Temperature Switch - Manual (Page 8)

8
Explanatory Notes
– continued –
Function
The temperature switch type TRS 5-7 is a two channel unit featuring automatic self-
checking in accordance with DIN 3440/VDE 0116 (regulations on protection circuits
for firing equipment of furnaces). The two channels are designed to monitor the
operation of each other. If one channel fails, an alarm signal is initiated,
simultaneously switching the output contacts to shut off the heat supply. The periodic
self-checking logic unit checks the two channel circuits for malfunction. The integrity
of the thermocouple is continuously monitored by the TRS 5-7. The output relays are
not influenced by this internal test.
A manual test push button is also provided. When the push button
TEST
1 is pressed,
a fault is simulated in the temperature sensor. There is also a toggle switch
TEST
2 /
INSPECTION
for simulating a malfunction in the self-checking unit.
The output contact relays of the temperature switch are of the normally closed type
and will therefore signal alarm condition in the event of a mains failure.
The temperature switch can signal the following three operating conditions:
■ Normal operation (temperature within permissible range)
■ Alarm (limit temperature exceeded)
■ Alarm (malfunction in temperature switch or resistance thermometer)
The green LED indicates “
POWER ON
”. The two red LEDs indicate excessive
temperature or system malfunction. The failure of one channel (loss of redundancy)
is signalled by the lighting-up of one red LED.
The equipment combination TRS 5-7 and TRG 5-... provides fail-safe protection
against a first fault, i. e. the system will still continue to provide the safety function
even after the occurence of a first fault.
Description
Self-monitoring temperature switch with periodic self-checking feature to be used in
conjunction with thermocouples type TRG 5-11, TRG 5-31, TRG 5-41.
The equipment operates as a safety temperature controller, or, in conjunction with an
external lock-out in accordance with VDE 0116, as a safety temperature limiter. An
alarm is given as soon as the temperature exceeds a preset limit value.
Application in steam boilers and (pressurized) hot-water plants operating without
constant supervision (TRD 604) as well as any other kind of heat generating units.
Design
TRS 5-7 b:
Plug-in unit in plastic case for snapping onto the supporting rail TS 35 x 15 to DIN
EN 50022 for installation in control cabinets.
TRS 5-7 c:
19" slide-in unit, front panel to DIN 41494, part 5, 12 TE*)
*) TE = division units (1 TE = 5.08 mm)