Casella CEL Microdust Pro real time dust monitor - Manual (Page 10)

MicroDust Pro Aerosol Monitoring System
10 Casella CEL
Signals
A 6-way port at the bottom of the MicroDust Pro instrument provides the
following connections;
• RS232 serial digital communications for connecting the instrument to a
PC
• An analogue output signal for connecting the instrument to a chart
recorder or to an external data logger.
Table 1. 6-way port
Pin Wire
colour
9-way D-type
pin and function
Function
1 Yellow N/A Analogue ground
2 Red N/A Analogue out
3 White 3 (TX out) RS232 receive in
4 Black 2 (Rx in) RS232 transmit
out
5 Blue 5 (Ground) Comms ground
4 (DTR
8 (CTS)
6 (DSR)
Linked together
The analogue output signal has a full-scale range of 0 to 2.5 volts and an output
impedance of approximately 500 Ω. The full-scale output voltage is
proportional to the full-scale indication of the active range. For example, if the
active range is 0 to 25 mg/m³, and output signal of 2.5 volts represents a dust
concentration of 25 mg/m³ (meaning the analogue output is scaled at 1 mV per
0.01 mg/m³).
IMPORTANT
The analogue output is available only when using a fixed measurement range (that is,
when NOT using Auto Range).