Operator Manual
Page
15
of
40
P/N 1580281
SEC3120 Digital Transmitter
Sensor Electronics Corporation
Rev 10, 20150707
Within the LOW, MID, HIGH and FAULT
pages the user can set:
-
the relay latching style **
-
the on delay in seconds (0-255)
-
the off delay in seconds (0-255)
-
the energized state (NO = relay not
energized until activated {resembles
normally open contact action}, YES =
relay energized until activated {
resembles normally closed contact
action })
** Latching Mode:
- Normal =
relays do not latch.
- Latching =
relays remain activated until forced reset.
- Audible =
relays can be silenced by user (forced off).
ENTER on ‘PREVIOUS MENU’ to return
to the Relay Menu and choose to
permanently save or abort the changes.
ENTER on ‘SAVE CHANGES’ to retain
new settings or ‘ABORT CHANGES’ to
cancel them. Either choice will return to
the Relay Menu.
Logic:
A key feature in the SEC3120 is the Sensor Role because only one set of relays is provided to service both
attached sensors. Therefore, in determining the sensor mode, a decision regarding how the relays will be
used must be considered and a decision concerning what relay mode is used must be made. Below is a
list of possible relay modes:
Sensor One
–
All alarm relays are determined exclusively from the alarm status of sensor one.
The fault relay is engaged by either a sensor one fault condition or an SEC3120 unit fault condition.
Alarm and fault states of sensor two will NOT cause any relays to be engaged. This relay mode is
commonly used in conjunction with the Single Sensor Role, and must be set PRIOR to setting the
Single Sensor Role.
Sensor Two
–
All alarm relays are controlled exclusively from the alarm status of sensor two. The
fault relay is engaged by either a sensor one fault condition or an SEC3120 unit fault condition.
Alarm and fault states of sensor one will NOT cause any relays to be engaged. CAUTION: Sensor
Two relay logic must not be used when the sensor mode is SINGLE.
Logical AND
–
All alarm relays are controlled by the logical AND condition of BOTH sensors one
and two states. This means that for a low-alarm relay to be engaged, BOTH sensors must be
reporting low relay alarm states (gas levels above the low alarm threshold). For a mid-alarm relay
to be engaged, BOTH sensors must be reporting at least mid-relay alarm states. For a high-alarm
relay to be engaged, BOTH sensors must be reporting high alarm states. This relay mode is best
utilized in the Identical Sensor Role, and should be set PRIOR to setting the Identical Sensor Role.
The fault relay will engage if EITHER sensor is reporting a fault condition, or if the SEC3120 unit is
in a fault state. CAUTION: AND or SENSOR TWO relay logic must not be used when the sensor
mode is SINGLE.
LOGIC MODE
PREVIOUS MENU
*
LATCH
‘NORMAL’
ON DLY
XXX
OFF DLY
XXX
ENERGIZED YES / NO
* PREVIOUS MENU
* SAVE CHANGES
ABORT CHANGES
