Teledyne M300EM operation manual Relay Pca Pn, STATUS LED’s, Status LED’s, Dc Voltage Test, Points

Theory of Operation Teledyne API – Technical Manual - Model 300E Family CO Analyzers

11.5.5.5.Status LED’s

Eight LED’s are located on the analyzer’s relay board to show the current status on the various control functions performed by the relay board. They are listed on Table 11-4.

Table 11-4: Relay Board Status LED’s

LED	COLOR	FUNCTION	STATUS WHEN LIT	STATUS WHEN UNLIT
D1	RED	Watch Dog Circuit	Cycles On/Off Every 3 Seconds under direct control of the
			analyzer’s CPU.
D2	YELLOW	Wheel Heater	HEATING	NOT HEATING
D3	YELLOW	Bench Heater	HEATING	NOT HEATING
D4	YELLOW	Spare	N/A	N/A
D5	GREEN	Sample/Cal Gas	Valve Open to CAL GAS	Valve Open to SAMPLE Gas Flow
		Valve Option	FLOW
D6	GREEN	Zero/Span Gas	Valve Open to SPAN GAS	Valve Open to ZERO GAS FLOW
		Valve Option	FLOW
D7	GREEN	Shutoff Valve	Valve Open to CAL GAS	Valve CLOSED to CAL GAS
		Option	FLOW	FLOW
D8	GREEN	IR SOURCE	Source ON	Source OFF

STATUS LED’s	DC VOLTAGE TEST
	POINTS

RELAY PCA

PN 04135

Figure 11-14: Location of relay board Status LED’s

11.5.5.6.I2C Watch Dog Circuitry

Special circuitry on the relay board monitors the activity on the I2C bus and drives LED D1. Should this LED ever stay ON or OFF for 30 seconds, the watch dog circuit will automatically shut off all valves as well as turn off the IR Source and all heaters. The GFC Wheel motor will still be running as will the Sample Pump, which is not controlled by the relay board.

246 04288D DCN5752