Teledyne gfc 7000ta operation manual 10.5.3. I2C Bus, Touchscreen Interface, LCD Display Module

Troubleshooting Model GFC7000TA Carbon Dioxide Analyzer

A voltmeter should be used to verify that the DC voltages are correct per the values in the table below, and an oscilloscope, in AC mode, with band limiting turned on, can be used to evaluate if the supplies are producing excessive noise (> 100 mV p-p).

Table 10-7: DC Power Supply Acceptable Levels

POWER	VOLTAG	CHECK RELAY BOARD TEST POINTS
SUPPLY		FROM TEST POINT		TO TEST POINT		MIN V	MAX V
	E
ASSY
		NAME	#	NAME	#
PS1	+5	Dgnd	1	+5	2	4.8	5.25
PS1	+15	Agnd	3	+15	4	13.5	16V
PS1	-15	Agnd	3	-15V	5	-14V	-16V
PS1	Agnd	Agnd	3	Dgnd	1	-0.05	0.05
PS1	Chassis	Dgnd	1	Chassis	N/A	-0.05	0.05
PS2	+12	+12V Ret	6	+12V	7	11.75	12.5
PS2	Dgnd	+12V Ret	6	Dgnd	1	-0.05	0.05

10.5.3. I2C Bus

Operation of the I2C bus can be verified by observing the behavior of D1 on the Relay PCA & D2 on the Valve Driver PCA . Assuming that the DC power supplies are operating properly, the I2C bus is operating properly if: D1 on the relay PCA and D2 of the Valve Driver PCA are flashing

There is a problem with the I2C bus if both D1 on the relay PCA and D2 of the Valve Driver PCA are ON/OFF constantly (steady lit or steady off)

10.5.4. Touchscreen Interface

Verify the functioning of the touchscreen by observing the display when pressing a touchscreen control button. Assuming that there are no wiring problems and that the DC power supplies are operating properly, if pressing a control button on the display does not change the display, any of the following may be the problem:

∙The touchscreen controller may be malfunctioning.

∙The internal USB bus may be malfunctioning.

You can verify this failure by logging on to the instrument using APICOM or a terminal program to any of the communications ports. If the analyzer responds to remote commands and the display changes accordingly, the touchscreen interface may be faulty.

10.5.5. LCD Display Module

Verify the functioning of the front panel display by observing it when power is applied to the instrument. Assuming that there are no wiring problems and that the DC power supplies are operating properly, the display screen should light and show the splash screen with logo and other indications of its state as the CPU goes through its initialization process.

Teledyne Analytical Instruments 242