Saftey Provisons - Honeywell 7800 Series Installation Instructions Manual

RM7888A 7800 SERIES RELAY MODULE
a. Limits Complete is not energized.
b. Special Function 2 is not energized
c. Flame failure.
d. Ignition energized.
e. Main energized.
f. Flame Proven is not energized.

SAFTEY PROVISONS

Interal Hardware Status Monitoring
The RM7888A analyzes the integrity of the configuration
jumper and internal hardware. The POWER LED blinks
every four seconds to signify an internal hardware check.
Closed Loop Logic Test
The test verifies the integrity of all safety critical loads
(terminals 8, 9, 10 and 21). If the loads are not energized
properly, for example, the main valve terminal is powered
during purge, the RM7888A will lockout on a safety
shutdown. The RM7888A must react to input changes but
avoid the occurrence of nuisance shutdown events. Signal
conditioning is applied to line voltage inputs to verify
proper op-eration in the presence of normal electrical line
noise such as transient high voltage spikes or short
periods of line dropout. Signal conditioning is tolerant of
synchronous noise (line noise events that occur at the
same time during each line cycle).
Dynamic Flame Amplifier and
Shutter Check
Self-checking circuitry tests all electronic components in
the flame detection system and amplifier 12 times per
minute and shuts down the RM7888A if the detection
system fails.
Dynamic Amplifiercheck™
Dynamic Amplicheck™ circuitry tests the flame signal
amplifier during burner operation and shuts down
RM7888A if the flame amplifier fails.
Dynamic Input Check
All system input circuits are examined to make sure that
the RM7888A is capable of recognizing the true status of
external controls, limits and interlocks. If any input fails
this test, a safety shutdown occurs and the fault is
annunciated.
Dynamic Safety Relay Test
Checks the ability of the dynamic safety relay contacts to
open and close. Verifies that the safety critical loads
(terminals 8, 9, 10 and 21) can be de-energized, as
required, by the Dynamic Self-Check logic.
Dynamic Self-Check Safety Circuit
The microcomputer tests itself and related hardware, and
at the same time, the safety relay system tests the
microcomputer operation. If a microcomputer or safety
relay failure occurs and does not allow proper execution of
the self-check routine, safety shutdown occurs and all
safety critical loads will be de-energized.
32-00214—01
Expanded Safe-Start Check
The conventional safe-start check, which prevents burner
start-up if flame is indicated at start-up, is expanded to
include a flame signal check during STANDBY, a safety
critical load check, a Limits Complete check, and an @Low
Fire check.
Off Cycle (Standby) Flame Signal
Check
The flame detection subsystem (flame detector and
amplifier) is monitored during STANDBY. If a flame
simulating condition or an actual flame exists for 40
seconds in STANDBY, a safety shutdown occurs and
startup is prevented. If the flame signal exists at any time
after 40 seconds during STANDBY, a safety shutdown
occurs and is annunciated.
• A shutter-check amplifier and self-checking detector
are energized continuously during STANDBY and the
last two seconds of STANDBY. If a flame exists, a safety
shutdown will occur.
• An Amplicheck™ Amplifier is energized continually
through STANDBY to detect any possibility of a
runaway detector or a flame. If either situation
happens, a safety shutdown will occur.
• A standard amplifier is energized continually through
STANDBY to detect any possibility of a runaway
detector or a flame. If either situation happens, a safety
shutdown will occur.
Tamper Resistant Timing Logic
Safety and logic timings are inaccessible and cannot be
altered or defeated.
Alarm Operation
This output will supply power to the system master and/ or
an external alarm indicator such as a bell or buzzer. The
alarm is turned on anytime a lockout has occurred and the
lockout condition has not been cleared. The alarm output
is also turned on when the reset button is pressed and
held for more than four seconds. The status of this output
is not monitored by the relay module.
First-Out Annuciation and Self-
Diagnostics
Sequence Status Lights (LEDs) provide positive visual
indication of the program sequence: POWER, PILOT,
FLAME, MAIN and ALARM. The green POWER LED blinks
every four seconds, signifying that the RM7888A
hardware is running correctly.
Optional Multi-function Keyboard Display Module shows
elapsed time during PILOT IGNITION and MAIN IGNITION.
As an additional troubleshooting aid, it provides RM7888A
SAFETY PROVISIONS sequence timing, diagnostic
information, and historical information when a safety
shutdown or hold or normal operation occurs.
First-out Annunciation reports the cause of a safety
shutdown or identifies the cause of a failure to start or
continue the burner control sequence with an English text
and numbered code via the Keyboard Display Module. It
monitors all field input circuits, including the flame signal
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