Teledyne 651 operation manual Data Communication Ports, RS-232 Serial Connections

Instrument Description Teledyne API Ultrafine Particle Monitor - Model 651

Data Communication Ports

USB Communication Port

The Model 651 provides a USB port for communications use.

RS-232 Serial Connections

The Model 651 provides one standard, 9-pin RS-232 serial port that allows communication between a computer and the particle monitor. Serial commands are sent to and from the computer to monitor instrument status information, to retrieve and monitor data, and to provide a variety of control functions such as turning the pump on and off. More information can be found in the Computer Interface section of Chapter 8 in this manual.

Analog Input

The Model 651 can monitor the analog voltage from an external source via the analog input BNC connector on the back panel (labeled Analog Input). The input voltage range for these ports is 0 to 10 V. Analog voltages can be displayed together with concentration data on the display screen and can be saved to the removable Flash Drive or a computer. Voltages from connected pressure, flow, or temperature transducers can be correlated to particle concentration in real time.

Amplification must be supplied by the user to bring low voltage signals to the appropriate 0 to 10 V range for best resolution.

DMA/Analog Out and Pulse Out

During normal operation of the Model 651, the Analog Out port provides an analog 0 to 10 V signal proportional (linear or log) to particle concentration. This particle concentration is corrected for coincidence and tracks the displayed concentration.

Pulse Out provides a 5-volt(50-ohm termination) digital pulse for each particle detected. This enables you to use your own counting electronics hardware and provides a particle trigger for special applications. The width of the pulse depends on both the shape of the photo detector pulse and the trigger-level of the pulse threshold. To provide accurate pulse counts, use a counter that is capable of counting pulses with a width of 50 nanoseconds or less.

Particle concentrations that have been calculated based on the particle counts from the counting electronics hardware are not live- time corrected for particle coincidence. Thus, when particle concentration is high, the concentration provided by this output might be lower than the displayed concentration. Appropriate coincidence correction should be applied when pulse output is used for high concentration measurements.

40 07506C DCN6727