Alarms And Relays; Alarms; Alarm Annunciators - Lakeshore 335 User Manual

74 c 5: Advanced Operation
HAPTER
5.7 Alarms and
Relays

5.7.1 Alarms

Model 335 Temperature Controller
Monitor Out settings depend on the Monitor Units selected, and are limited to the
acceptable values of the selected units.
Default:
PolarityQUnipolar
Monitor Out 0 V and -10 VQ0.0000 K
Monitor Out +10 VQ1000 K
Interface Command: ANALOG
Each input of the Model 335 has high and low alarm capability. Input reading data
from any source can be compared to the alarm setpoint values. A reading higher than
the high alarm setpoint triggers the high alarm for that input. A reading lower than
the low alarm setpoint triggers the low alarm for that input.
Menu Navigation:
AlarmQInput (A, B)QAlarm (Off, On)
AlarmQInput (A, B)QAlarm (On)QLow Setpoint (see note below)
AlarmQInput (A, B)QAlarm (On)Q
Low and High Setpoint limits are determined by the Preferred Units of the associated sen-
sor input.
Defaults:
AlarmQOff
Low SetpointQ0.0000 K
High SetpointQ1000 K
Interface Command: ALARM

5.7.1.1 Alarm Annunciators

The Alarm LED annunciator steadily displays when any alarm that is enabled also has
the Visible parameter enabled. The annunciator flashes when an alarm with the Visi-
ble parameter enabled activates. An input need not be displayed for the system Alarm
annunciator to indicate input alarm status, but if the input is displayed on the front
panel, then the reading will alternate between the alarm status message and the
actual reading. If the Audible parameter is set to On for an enabled alarm, then the
beeper inside the instrument will sound when the alarm activates. The two relays on
the Model 335 can also be tied to alarm functions as described in section 5.7.2. You
may want to set the Visible parameter to Off if there is no need for showing the alarm
state on the front panel, for instance, if you are using the alarm function to trigger a
relay. The Audible parameter can be set to Off as well to keep the audible alarm from
sounding when an alarm is triggered.
Menu Navigation:
AlarmQInput (A, B)QAlarm (On)Q
AlarmQInput (A, B)QAlarm (On)Q
Default:
VisibleQOn
AudibleQOn
Interface Command: ALARM
QHigh SetpointQ(see note below)
ENTER
QVisible (Off, On)
ENTER
QAudible (Off, On)
ENTER