To provide optimum protection against corrosive environments all parts of the PA-2 Mercury Analyzer are enclosed in an industrial-grade cabinet made of fibreglass-reinforced polyester (protection class IP 66; NEMA 4X; etc.). The electronic circuitry is shielded from the wet chemical section by a chemically resistant wall.

PA-2 for continuous monitoring of Hg in scrubber water (coal fired power station, Germany)	PA-2 reading the Hg concentration of effluents (chlor-alkali plant, Germany)

The PA-2 analyzer is controlled by a built-in computer and operates fully automatic. The continuous measuring mode can be switched over to a periodic measuring mode (for example 10 minutes of measurement every hour). Auto-Cal. Check: periodically the instrument switches from the sample stream to a calibration solution to check any deviation from the reference value. A status signal is generated if the value measured is out of range. Auto-Zero: the zero line of the analyzer is adjusted automatically after a preset period of time. Self-Cleaning: Precipitations like manganese dioxide are dissolved by an automatic rinse step which makes manual cleaning superfluous.

The PA-2 is operated via a waterproof membrane keypad. All inputs required are selected in a readily understandable menu shown on the graphical display. It is also possible to initiate some functions like Auto Zero from an external computer via the RS 232 interface.

The analytical results are continuously displayed on an LCD in micrograms per litre and as absorption units. A linear electrical signal (4 ... 20 mA) is also output and can be connected to a recorder or to the analog input of a data aquisition system.

The PA-2 is equipped with sensors to detect malfunctions of the system and triggers an alarm for the operator. The following functions/malfunctions are checked and indicated:

	Reagent flow
	Sample flow
	Stripping air flow
	Leakage of fluids
	Photometer lamp
	Calibration

These features permit reliable unattended operation. Malfunctions are reported to the user both optically and via a status signal.

The PA-2 is not a laboratory analyzer simply converted for process applications but has especially been designed for operation under harsh industrial conditions. The number of parts subject to wear has been minimized and particularly durable components have been chosen for use in critical locations. This results in extended maintenance intervals. The stripping unit is based on an aerosol-free principle and the need for cleaning the optical cell is particularly low.

The following data is available at the serial RS 232 interface: Actual mercury concentration Status (Ready - Maintenance - Malfunction)

Thanks to the bidirectional interface, operational functions like "Zero Adjustment", "Calibration Check" and "Start Measurement" can be triggered externally