Emerson 2468CD, 2468CB manual 2.6FAULT ANALYSIS & CORRECTIVE ACTION, 2-23

Hydrastep 2468CB and 2468CD Manual 2468CB & 2468CD Dual Power Supply Version

2.6FAULT ANALYSIS & CORRECTIVE ACTION

Faults in the system will generally be indicated by the YELLOW LED on the front panel and by the fault output on the display board. The main faults, which are catered for, are:

∙Water above steam condition

∙Electrode or Wiring fault

∙Detection of an internal circuit fault

When any of the above mentioned conditions exist within the Hydrastep 2468CB system, the yellow LED is illuminated to indicate the FAULT state. Since the electrode inputs are split between the two input boards, the ALARM indicator is configured to differentiate between ODD and EVEN electrode faults. An opto-coupler output, normally short-circuited, becomes open-circuited on a FAULT state, providing an ALARM indication output for external use. The current output indicates an alarm condition by a 0.5Hz waveform superimposed on the main analogue signal.

A further FAULT is indicated when the number of electrodes switch on the display board is set to an invalid number. This error brings up an alternate LED illumination display, that is a chequered display of GREEN and RED LEDs on the two front panel columns.

WARNING Mains voltages are present in this instrument when power is connected. De-energise before opening front cover.

Some parts of the water column and electrodes may be very hot. Please ensure parts are adequately cooled or that suitable precautions are taken before handling.

	Indication	Fault(s)	Analysis and Corrective Action
	State 1	Water conductivity.	Check ac voltage on all electrodes immersed in
	Top and	All LED pairs in water	water with a true r.m.s. voltmeter. If several of the
			immersed electrodes show a voltage of less than
	bottom	alternating between
			approximately 0.1V ac then very high water
	halves of	water and steam.
			conductivity is probable.
	fault LED
	illuminated		Check water column installation is correct; sloping
	One or more		pipework and insulation details. Make sure that
	LED pairs		there is sufficient condensate flow through the
	alternating		column.
	between		If the normal water conductivity is high, the
	water and		electrode error circuit can be de-sensitised or
	steam		disabled.
			If the normal water conductivity is still too high
			(40mV ac at electrode), the electrode error circuit
			must be disabled – refer to the electrode error
			configuration section.
		Water above steam,	The electrode channel(s) causing the problem will
		caused by electrode	be evident from the unit display by an alternating
		wiring or internal fault	indication in the steam area.
		Electrode connection	Check the suspect electrode(s) has the correct pair
		open-circuit or short-	of conductors connected, check the connections to
		circuit to earth	the input board. Rectify if incorrect.
		Table 2.3 - Fault analysis/corrective action chart
24685034			2-23