Model 400E Instruction Manual APPENDIX A-4: M400E Signal I/O Definitions, Revision .2
SIGNAL NAME BIT OR
CHANNEL
NUMBER
DESCRIPTION
B status outputs, U27, J1018, pins 1–8 = bits 0–7, default I/O address 324 hex
ST_DIAG_MODE 0 0 = in diagnostic mode
1 = not in diagnostic mode
ST_LOW_SPAN_CAL 1 0 = in low span calibration
1 = not in low span
ST_LAMP_ALARM 2 0 = any lamp alarm
1 = all lamps OK
3–7 Spare
Front panel I
2
C keyboard, default I
2
C address 4E hex
MAINT_MODE 5 (input) 0 = maintenance mode
1 = normal mode
LANG2_SELECT 6 (input) 0 = select second language
1 = select first language (English)
SAMPLE_LED 8 (output) 0 = sample LED on
1 = off
CAL_LED 9 (output) 0 = cal. LED on
1 = off
FAULT_LED 10 (output) 0 = fault LED on
1 = off
AUDIBLE_BEEPER 14 (output) 0 = beeper on (for diagnostic testing only)
1 = off
Relay board digital output (PCF8575), default I
2
C address 44 hex
RELAY_WATCHDOG 0 Alternate between 0 and 1 at least every 5 seconds to
keep relay board active
O3_SCRUB_HEATER 1 0 = O
3
scrubber heater on
1 = off
2–5 Spare
SPAN_VALVE 6 0 = let span gas in
1 = let zero gas in
PHOTO_REF_VALVE 7 0 = photometer valve in reference position
1 = measure position
CAL_VALVE 8 0 = let cal. gas in
1 = let sample gas in
9–13 Spare
PHOTO_LAMP_HEATER 14 0 = O
3
photometer lamp heater on
1 = off
O3_GEN_HEATER 15 0 = O
3
generator lamp heater on
1 = off
Rear board primary MUX analog inputs
PHOTO_DET 0 Photometer detector reading
O3_GEN_REF_DET 1 O
3
generator reference detector reading
2 Spare
SAMPLE_PRESSURE 3 Sample pressure
4 Temperature MUX
5 Spare
SAMPLE_FLOW 6 Sample flow
TEST_INPUT_7 7 Diagnostic test input
TEST_INPUT_8 8 Diagnostic test input
04402 Rev C.3 17
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