Honeywell SEARCHLINE EXCEL PLUS Technical Manual

53Chapter 8 Operation and Configuration
Searchline Excel™ Plus / Searchline Excel™ Edge – Technical Manual
See the following table for output levels:
Mode Default Value (mA) Min Value (mA) Max Value (mA)
Discrete Mode Proportional
Mode
Fault 1 0 3.6
Inhibit 2 1 3.6
Warning 3 1 4
Normal 4 Proportional to
gas concentration
4 20
Alarm 20 Not available 4 20
Over-range 21 20 22
8.2.3Relay Signalling
Searchline Excel Plus & Searchline Excel Edge are equipped with three independent relays, designated for Fault, Alarm1
and Alarm2. These relays are safety-related outputs and are compatible for use in SIL1 applications. The Fault relay is used
for indication of various fault conditions; the Alarm1 and Alarm2 relays are used to indicate alarm conditions. All the relays
are configurable, giving an option of Normally Energised / De-energised and latching / non-latching of events.
CAUTION
!
Fault relay will be triggered when user performs Inhibit operation.
8.3Normal Operation
During normal operation, the 4–20 mA output indicates the gas concentration.
The output is:
1. Linear within the range of gas concentration in Proportional mode
2. 4 mA in Discrete mode
Searchline Excel Plus & Searchline Excel Edge are able to zero very slow increases in path integral concentration, e.g., of
free-moving hydrocarbons.
The compensation happens immediately after power-up. The value of compensated gas reading is limited to an absolute
value.
8.4Operation During Fault
If Fault is indicated the visual indicator starts to flash in yellow, the fault relay is de-energized and 420 mA loop is set
to 1 mA.
Analog outputs lower than 4 mA and higher than 20 mA represent diagnostic information. The fault relay in this mode is
normally energized and the visual indicator is lit steady green.
NOTE:
HART communication requires >1 mA current output to support transmission. If the fault level is configured to be below 1 mA,
HART communications will cease.
8.5Operation During Alarm
Searchline Excel Plus & Searchline Excel Edge feature three levels of alarm: Low Alarm, Alarm and Over-range.
8.5.1Low alarm
During Low Alarm, the Alarm1 relay is energized/de-energized depending on its configuration. The 4–20 mA loop is set
to 16 mA in Discrete mode. It is proportional to gas concentration in Proportional mode. The visual indicator flashes red.

Honeywell SEARCHLINE EXCEL PLUS Specifications

General

Brand	Honeywell
Model	SEARCHLINE EXCEL PLUS
Category	Gas Detectors
Language	English