Casella CEL Microdust 880 IS real time dust monitor - Manual (Page 20)

Microdust 880nm & WinDust Application Software
Handbook HB3255-03
Page 20 of 51
Wiring Details - (6 way mini DIN plug)
View of plug solder buckets
Function Pin Number Wire Colour 9 Way D Type
(P.C RS232)
Analogue ground 1
(C)
Yellow N.A
Analogue Out 2
(B)
Red N.A
RS232 Receive in 3
(D)
White 3
(TX out)
RS232 Transmit out 4
(A)
Black 2
(RX in)
Coms ground 5
(H)
Blue 5
(Ground)
4
(DTR)
, 8
(CTS)
, 6
(DSR)
Linked together
The analogue output signal has a full scale range of 0-2.5 volts and an output impedance of
approximately 1k
Ω
. The full scale output voltage is equated to the full scale indication of the active
range, (for example, if the active range is 0-25mg/m3 then an output signal of 2.5 volts will
correspond to a dust concentration of 25mg/m3, ie 1mV per 0.01mg/ m3).
To avoid potential scaling errors when using the analogue output, the instruments operating ‘Range’
should be fixed to either the ‘High’ or ‘Low’ range and not to ‘Automatic’.
Care should also be exercised if using the ‘Offset readings’ function since the analogue signal
represents the dust concentration displayed before any offset calculation is applied.