Casella CEL Sensus data logger unit - Manual (Page 41)

Alarm Output Channels:
4 alarm output channels
2 available from the main connector panel 2 via expansion port
Primary channels (main connector):
These have open-collector outputs, suitable to drive relays on external
equipment.
Secondary channels (expansion port):
These are 5 V logic outputs, which require additional buffering
between them and any external equipment.
Alarm Channels:
16 alarm channels, each of which is capable of activating any of the
‘alarm output channels’.
Each alarm channel can be programmed to act individually or in
combination with other alarms to cater for complex alarm conditions.
Each channel includes:
Identity (Free text, used when notifying external equipment of alarm
conditions) Sounder (used to notify alarm condition) Test mode
(Identifies the type of comparison to make)
EQ
data equal to limit value
NEQ data not equal to limit value
GT data greater than limit value
LT data less than limit value
LT or GT data less than first limit or greater than
second limit value
GT and LT data greater than first limit and less than
second limit
Action (Identifies how alarms interact)
NONE
alarm is independent from any others
OR alarm result is “or’d” with result of
next alarm
AND alarm result is “and’ed” with result of
next alarm
Fast mode alarm can trigger a change in both the channel scan and
data logging rates, in the presence of an alarm condition.
State delays where each change of ‘alarm state’ can have a delay
allocated to it, thereby no action is taken until the alarm state has
been steady for the specified time.
Data values that can be assigned for alarm-on and alarm-off; these
get transferred to a specified data channel when the alarm’s state
changes.
Specification SENSUS Digital Data Logger -
Users Handbook
Page 41 of 44