Scott Instruments 087-0007G Safety, Setup, Operation & Maintenance Manual Download Page 32

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Model 4688-IR / Model 4679-IR

Operation & Maintenance Manual

Manual #087-0007G, 10/2003

The GasPlus-IR has 3 optional alarm relays: 2 concentration alarms and 1
fault alarm. Active alarms are displayed on the LCD as shown in the figure to
left.

The appearance of these display indicators does not imply that the

associated relay is also active, since the relays are inactive during
inhibit.

When the

INHIBIT

indicator is visible, alarm and fault conditions may

be indicated, but their associated relays are held in their normal states (note:
fail-safe relays will be held energized during inhibit).
Alarms are inhibited automatically at power on (for 30 seconds), and by
touching the Z (Zero) key briefly with the magnet (See

"General Operations:

Inhibiting Alarms"

). When the Z (Zero) is used, alarms are inhibited for 9

minutes. The period may be reprogrammed by changing the value of the

AL.IP

parameter in the USER menu.

Changing Alarm Set

Changing Alarm Set-Up P

-Up P

-Up Parameters

arameters

Using the Scott Instruments magnet, access the USER menu and select the
desired alarm parameter. Use the Up or Down arrow keys to increment or
decrement the value, then touch the magnet to the E (Enter) key to store the
reading (observe "SEt" on the display) or the Esc (Escape) key to abort. Use
the Z (zero) key to return to the RUN mode.

Set P

Set Points and R

oints and R

oints and Reset P

eset P

eset Points

oints

An alarm set point (i.e., A1.SP) is the gas concentration level at which the
alarm relay becomes active. A reset point (i.e. A1.RP) is the gas
concentration level at which the alarm relay deactivates (note that if the alarm
is used in latching mode, the relay will have to be manually reset).

You must always configur

ou must always configur

ou must always configure both the Set P

e both the Set P

e both the Set Point and Reset P

oint and Reset P

oint and Reset Point for

oint for

both concentr

both concentration alarms

ation alarms

ation alarms. Since the Set P

. Since the Set P

. Since the Set Point cannot be

oint cannot be

progr

programmed below the Reset P

ammed below the Reset P

ammed below the Reset Point, you may be r

oint, you may be r

oint, you may be requir

equir

equired to first

ed to first

lower the Reset P

lower the Reset Point. Likewise, the Reset P

oint. Likewise, the Reset P

oint. Likewise, the Reset Point cannot be

oint cannot be

progr

programmed higher than the Set P

ammed higher than the Set P

ammed higher than the Set Point, so you may be r

oint, so you may be r

oint, so you may be requir

equir

equired to

ed to

first r

first raise the Set P

aise the Set P

aise the Set Point.

oint.

NOTE: P

NOTE: Pur

ure Methane and Hexane tr

e Methane and Hexane tr

e Methane and Hexane transmitters can be progr

ansmitters can be progr

ansmitters can be programmed

ammed

with falling alarms

with falling alarms.....

Set and Reset Delays

A set delay prevents an alarm from activating until the alarm condition has
been above the setpoint for a certain amount of time. A reset delay prevents a
non-latching alarm from deactivating until the alarm condition has been below
the reset point for a certain amount of time.
Reset delays are often used to control ventilation fans (i.e., the fans are kept
on past the danger point to ensure that the hazardous condition is absent
throughout the area and not just around the transmitter. Set delays are
sometimes used to avoid "nuisance trips". No set delay is available on the
"high-high" alarm.

The use of lengthy set delays is strongly discouraged

by Scott Instruments

Alarm 2 should

always be

configured as a

latching alarm. If

the A2.OP setting

is "0" or "1" (non-

latching), the

instrument should

be connected to

an auxiliary