Aethlabs microAeth MA200, Operating Manual

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50 microAeth
®
MA Series MA200, MA300, MA350 Operating Manual microAeth
®
MA Series MA200, MA300, MA350 Operating Manual 51 AethLabs AethLabs
Each command is framed by either <STX> at the start and terminated with <ETX> or without a start and
terminated only with <CR>. If a command is terminated with <ETX> then additional two characters <BCC>
block checksum is attached after <ETX>.
AethLabs’ implementation of the Hessen protocol does not itself support multi-drop installations, the
instrument instead responds to broadcast command messages that do not specify an instrument ID. As
the MA Series instruments do not have a traditional zero or span mode, normally associated with gas
monitors, this functionality is not supported. MA Series instrument serial ports are 3.3v TTL logic level
serial. Care must be taken when interfacing to this hardware as it is not isolated. Minimum serial baud rate
communication speed for the MA Series instruments is 57600 baud.
Command for AethLabs Implementation of Bayern-Hessen Protocol
Command Message Description Examples
DA Data Query Command
<STX>DA<ETX><BCC> (<STX>DA<ETX>04)
OR
DA<CR>
NOTE: It is possible to make the same request simply by sending 'DA <CR>' not using <STX>, <ETX>, and
<BCC>.
Bayern-Hessen Protocol Response Message Fields
Message Field Length
(bytes)
Description
<STX> 1 Start of text character (ASCII code 0x02)
MD 2 'MD' is the message header.
<aa> 2
This is the number of gases (AethLabs measurements) being reported
in the message
<SP> 1 Space character (ASCII code 0x20)
<nnn> 3 Three-digit gas (AethLabs measurement) ID number.
<SP> 1 Space character (ASCII code 0x20)
<smmmmsee> 8 Gas (AethLabs measurement) concentration.
<SP> 1 Space character (ASCII code 0x20)
<oo> 2
8 operational status bits, formatted as a two digit hexadecimal
number.
<SP> 1 Space character (ASCII code 0x20)
<ff> 2 8 failure status bits, formatted as a two digit hexadecimal number.
<SP> 1 Space character (ASCII code 0x20)
<iii> 3 Three-digit instrument ID number.
<SP> 1 Space character (ASCII code 0x20)
000000 6 Spare field. Set to all zeros.
<SP> 1 Space character (ASCII code 0x20)
<ETX> 1 End of text character (ASCII code 0x03)
<BCC> 2 Block checksum
TOTAL 9 + 30 x A
'A" is the number of gases (AethLabs measurements) being reported
in the message.
Response Message for AethLabs Implementation of Bayern-Hessen Protocol
Complete Response for Data Query Command (DA):
<STX>MD<aa><nnn><SP><smmmmsee><SP><oo><SP><ff><SP><iii><SP>000000<SP><SP><smmm
msee><SP><oo><SP><ff><SP><iii><SP>000000<SP><SP><smmmmsee><SP><oo><SP><ff><SP><iii
><SP>000000<SP><SP><smmmmsee><SP><oo><SP><ff><SP><iii><SP>000000<SP><SP><smmmm
see><SP><oo><SP><ff><SP><iii><SP>000000<SP><SP><smmmmsee><SP><oo><SP><ff><SP><iii><
SP>000000<SP><SP><smmmmsee><SP><oo><SP><ff><SP><iii><SP>000000<SP><ETX><BCC>
Preamble of Response:
<STX>MD<aa><nnn>
For each data line measurement returned: (e.g. UV BC1, Blue BC1, Green BC1, Red BC1, IR BC1,
FlowTotal, Tape Postion):
<SP><smmmmsee><SP><oo><SP><ff><SP><iii><SP>000000<SP>
End of Response:
<ETX><BCC>
If the instrument is in SingleSpot mode, BC1 value for each optical wavelength will be returned. If the
instrument is in DualSpot mode, the BCc (compensated) value for each optical wavelength will be returned.
The instrument will provide the following channel values in response to a ‘DA’ command message:
Response Message for AethLabs Implementation of Bayern-Hessen Protocol
Measurement / Status Data Units / Format
SingleSpot mode:
UV BC1 Nanograms per cubic meter (ng/m
3
) (Integer)
Blue BC1 Nanograms per cubic meter (ng/m
3
) (Integer)
Green BC1 Nanograms per cubic meter (ng/m 3 ) (Integer)
Red BC1 Nanograms per cubic meter (ng/m
3
) (Integer)
IR BC1 Nanograms per cubic meter (ng/m
3
) (Integer)
FlowTotal Milliliters per minute (ml/min) (Decimal number)
Tape Position Whole number
DualSpot mode:
UV BCc Nanograms per cubic meter (ng/m
3
) (Integer)
Blue BCc Nanograms per cubic meter (ng/m
3
) (Integer)
Green BCc Nanograms per cubic meter (ng/m
3
) (Integer)
Red BCc Nanograms per cubic meter (ng/m 3 ) (Integer)
IR BCc Nanograms per cubic meter (ng/m
3
) (Integer)
FlowTotal Milliliters per minute (ml/min) (Decimal number)
Tape Position Whole number