MSA Senscient ELDS 1000 series, Руководство по эксплуатации

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System Description
Senscient ELDS™
Rev 15 27
GB
Beamblock Priority over Gas controls how the unit responds when the beam is blocked in the
presence of gas. Normally, ELDS units signal an error current (2.5mA by default) to indicate that
the beam is blocked. In the presence of gas, however, this behaviour is changed such that the last
gas value detected is maintained on the 4-20mA outputs whenever a beam-block occurs.
Optionally users can change this behaviour (for firmware versions 002.010.009 or later) such that
the ELDS does not ‘latch’ the last gas level but rather will signal the Beam-Block current even if
gas was being reported when the obstruction occurs.
Zero Unit
Units are normally ‘zeroed’ during installation; however it is also possible to repeat the zero
process at any time. This is recommended if a unit is physically disturbed (for example if the
alignment is inadvertently changed) or if units exhibit fingerprint or bad zero errors.
Change Tag
The unit ‘tag’ is normally assigned during installation but may be amended at any subsequent time
as required.
4-20mA Configuration
This tab provides information on the range of ‘fault’ conditions that apply to the unit and which will
be signalled over the 4-20mA current loop. A description of the configuration of this is provided in
section 4.5.2, item 8 therein. This tab provides repeat access to this facility should the original
arrangement require adjustment at a later time.
MODBUS
MODBUS support is available from all current ELDS units and is also historically supported for
most units. Units are not shipped with MODBUS support active and this tab provides a mechanism
to allow MODBUS to be configured and activated as required.
MODBUS shares the RS485 communication link, once MODBUS is activated then normal
interaction with the unit using SITE can only be undertaken using the Bluetooth link.
Ensure that Bluetooth communication is available with a unit prior to activating MODBUS
as without it further modifications or inspection of the unit with SITE will not be possible.
MODBUS can be activated through either a Bluetooth connection or via an RS485 link, however
Senscient recommend the use of a Bluetooth link when activating MODBUS. The following options
are presented on the MODBUS screen.
The Address must be assigned as required and must be in the range 1 to 247. This is a unique
value that identifies the unit on the MODBUS link.
Baud defines the communication speed that will apply, the default setting is normally 9600
however other rates are supported and can be selected as required.