Testing The Keypad; Diagnostics Mode Tests - Novatech 1730 Series Reference Manual

Novatech Controls

Testing the Keypad

This second preliminary test will check the functionality of the interrupt driven hardware informing the
MCU when a key press is detected, as well as testing each of the physical buttons integrated into the
lexan on the front panel of the transmitter.
The transmitter will display the message 'Press All Keys...', and the technician should press each key on
the front panel one at a time. While being depressed, the display will indicate on the display which
button is being detected. Once all eight buttons have been individually pressed and released the
transmitter will progress to the numbered diagnostics mode tests.
The keypad inputs are transmitted to the main PCB along the same data bus as the display. Changes to
the keypad triggers an interrupt on the MCU, which causes the device to process the key press. If this
interrupt is not working properly then Diagnostics Mode will inform the technician of this fault. In this
case the keypad will continue to work in Diagnostics Mode, but will not work in the normal runtime
loop.
The cause of a keypad interrupt failure may be the SPI chip IC7 on the display PCB is damaged, or that
the transistor buffer TR1 (display PCB v1.0E and earlier) or NAND gate IC8 on the display PCB is
damaged. In either case, the easiest way to fix a keypad interrupt failure is to swap out the entire
display PCB and repeat the test.

Diagnostics Mode Tests

01. Reference Voltages Summary
Overview: This non-interactive test gives a summary of the three main voltage references as read by
the internal ADC.
Option Up/Down: no operation
Enter: no operation
The purpose of this test is to provide a quick overview of the three main ADC reference voltages as read
by the reference voltage feedback and calibration circuit. At a glance it may be possible to confirm
whether the ADC circuitry is working properly or requires further testing.
The display has a table with three rows and three columns. Each row shows the reference voltage, ADC
count number for the zero mV reference and the ADC count number for the span mV reference.
50mV 275 ± 75
200mV 275 ± 75
1200mV 275 ± 75
If all of the numbers on both the middle and right column read within tolerance then it can be safely
assumed that the voltage reference circuitry, analog channel selection circuitry, multiplexers, gain
circuitry and ADC chips are working correctly.
If any of the numbers are reading outside of the expected ranges, especially if any are reading 0 or 4095
then there is a problem with the analog circuitry.
Potential faults are the DC-DC isolated power supply PS4, the two voltage regulators IC11,IC27, the
voltage reference IC25, channel selection multiplexers IC8,IC9, gain op-amp IC14, gain select multiplexer
IC24, analog-digital converter IC23, or the analog switch IC7.
Document Revision 1.03
1730 Series Diagnostics Mode Reference Manual
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Page 4 of 16 Diagnostics Mode v1.08