Watlow EZ-ZONE RMC - Manual (Page 167)

Watlow EZ-ZONE ® RMC Module • 164 • Chapter 7 Features
Alarm Latching
A latched alarm will remain active after the alarm
condition has passed. It can only be deactivated by
the user and only when the alarm condition no longer
exists.
If using an RUI an active message, such as an
alarm message, will cause the display to toggle be-
tween the normal settings and the active message in
the upper display and [Attn] in the lower display. To
clear a latched alarm:
1. Push the Advance Key
‰ to display [ignr] in the
upper display and the message source in the lower
display.
2. Use the Up ¿ or Down ¯ keys to scroll through
possible responses, such as Clear [`CLr] or Silence
[`SiL]
.
3. Push the Advance ‰ or Infinity ˆ key to execute
the action.
Without an RUI, a latched alarm can be reset by
cycling power to the module or configuring an Ac-
tion function within the control to perform a reset.
Do this by setting the Action Function to alarm and
trigger the Action to occur through Source Function
A.
An alarm that is not latched (self-clearing) will de-
activate automatically when the alarm condition has
passed. Turn Alarm Latching [`A;LA] on or off via
the Setup Page, Alarm Menu.
Normal Operating Range
Alarm High
Set Point
Time
Temperature
Alarm Low
Set Point
Alarm Response with Hysteresis
The alarm state continues until the
temperature drops to the Alarm High
Set Point minus the hysteresis. A
latching alarm could be turned off by
the operator at this point. A
non-latching alarm would turn off
automatically.
The alarm state begins when the temperature
reaches the Alarm High Set Point
Process
Temperature
Alarm Hysteresis
Alarm Silencing
If alarm silencing is on the operator can disable the
alarm output while the controller is in an alarm
state. The process value or temperature has to enter
the normal operating range beyond the hysteresis
zone to activate the alarm output function again.
If using an RUI an active message, such as an
alarm message, will cause the display to toggle be-
tween the normal settings and the active message in
the upper display and [Attn] in the lower display. To
silence an alarm:
1. Push the Advance Key
‰ to display [ignr] in the
upper display and the message source in the lower
display.
2. Use the Up ¿ and Down ¯ keys to scroll through
possible responses, such as Clear [`CLr] or Silence
[`SiL]
.
3. Push the Advance ‰ or Infinity ˆ key to execute
the action.
Without an RUI, silencing aa alarm can be accom-
plished by configuring an Action function within the
control to silence the alarm. Do this by setting the
Action Function to Silence and trigger the Action to
occur through Source Function A.
Turn Alarm Silencing [`A;Si] on or off via the
Setup Page, Alarm Menu.
Alarm Blocking
Alarm blocking allows a system to warm up after
it has been started up. With alarm blocking on, an
alarm is not triggered when the process tempera-
ture is initially lower than the alarm low set point
or higher than the alarm high set point. The process
temperature has to enter the normal operating range
beyond the hysteresis zone to activate the alarm
function.
If the RMC module has an output that is function-
ing as a deviation alarm, the alarm is blocked when
the set point is changed, until the process value re-
enters the normal operating range.
Turn Alarm Blocking [`A;bL] on or off via the
Setup Page, Alarm Menu.
Resetting a Tripped Limit
When a limit controller is ordered (RMC[5,6] _ [5,6] _
[5,6] _ [5,6] _ _ _ _ _) output 2 (digit 4), output 4 (digit
6), output 6 (digit 8) or output 8 (digit 10) will always
be a Form A (normally open) Mechanical Relay and
it will always be internally tied to the limit function.
When the limit is in a safe state the internal coil for
this relay will be energized, therefore the relay will
be closed. When a condition occurs that causes the
limit to trip, the internal coil will deengerize caus-
ing the relay to latch open. When the condition that
caused the limit to trip has been resolved, the relay
will remain latched open until reset. The process to
reset a latched limit can be different from control to
control and is dependent upon the controller firm-
ware version.
To check the firmware revision of your control do
one of the following:
If Used in Conjunction with an Remote User In-
terface
1. Navigate to the RMC Factory Page by simultane-
ously pushing and holding the Advance Key ‰
and the Infinity ˆ for approximately 8 seconds
and then use the up or down arrow key to navigate
to the Diagnostic Menu. Once there, push the Ad-
vance Key twice where the revision [`reu] will be
shown in the lower display and the upper display
will indicate the current firmware revision.