Watchdog Indicator (D1); Motherboard - Teledyne T750 User Manual

LED
D1
D2-5
D7
1
D8
2
D9
D6 1,2
D13
D10
D11 - 14
D15 1
D16 2
1 On T750, only applies when photometer option installed.
2 On T750, only applies when O

Watchdog Indicator (D1)

The most important of the status LEDs on the power distribution board/Relay board is the
2
red I C Bus watchdog LED. It is controlled directly by the calibrator's CPU over the I
bus. Special circuitry on the power distribution board watches the status of D1. Should this
LED ever stay ON or OFF for 30 seconds (indicating that the CPU or I
functioning) this Watchdog Circuit automatically shuts all valves and turns off all heaters
and lamps.
M
OTHERBOARD
This is the largest electronic assembly in the calibrator and is mounted to the
communications and output panel as the base for the CPU board and all I/O connectors.
This printed circuit assembly provides a multitude of functions including A/D conversion,
digital input/output, PC-104 to I
a pass through for the RS-232 and RS-485 signals.
166
Table 9-1. Power Distribution Board Status LEDs
DESCRIPTION
Watchdog Circuit; I 2 C bus
operation.
Photometer Meas/Ref Valve
O Generator Valve status
3
Photometer Pump status
GPT Valve status
Diluent Gas Valve status
Cal Gas Valve status
Photometer Heater Status
O Generator Heater Status
3
generator option installed.
3
2
C translation, temperature sensor signal processing and is
FUNCTION
Blinks when I 2 C bus is operating
properly
SPARE
When lit, the valve opens the
REFERENCE gas path
When lit, the valve open to O
gas path
When lit, the pump is turned on.
When lit, the valve opens the GPT
Chamber
When lit, the valve is open.
When lit, the valve is open.
SPARE
When lit, the photometer UV lamp
heater is on
When lit, the O generator UV lamp
3
heater is on
generator
3
2
C
2 C bus has stopped
083730750B DCN8606