Digital Inputs; Alarm Relays - Novatech 1730 Series Reference Manual

Novatech Controls 1730 Series Diagnostics Mode Reference Manual
If there is an analog signal at D1/D2, but not on the output then the problem is likely to be the power
transistor TR4/TR5 or the op-amp IC12/IC13. Check also that the light emitting diode LED4/LED5 is
working and that the legs of the LED have not become twisted inside the long standoff.

20. Digital Inputs

Overview: The digital inputs being tested include the four inputs from the dip-switch SW1, the 0.1"
jumper SW5 and the two inputs on the terminals marked 'Flow SW' and 'Burner Input'.
Option Up/Down: no operation
Enter: no operation
To test each of the dip-switch inputs, toggle them each individually and confirm that the display changes
to reflect a change in the physical state. If any of these digital inputs do not work as expected then try
manually shorting the associated pins on the IC using a small piece of wire to test whether the dip-
switch is damaged. Check the tracks going back to the MCU for damage.
To check SW5 use a small jumper to short the pins, observing the state change on the display
accordingly. If this does not work as expected then check the track to the MUC pin P2_6.
To check the Flow SW and burner input use a small terminal connector to short the terminal input pins
16 & 17 for the Purge Flow Switch, and terminal input pins 10 & 11 for the burner input.
If these digital inputs fail to work as expected, check the associated circuitry and tracks to the MCU.
Both inputs have a transistor between the input and the MCU for protection. The burner input also has
two micro-fuses in series with each pin and a transient voltage suppressor across the terminals for
additional protection. If any of these devices are damaged then consider the cause for this damage
while replacing the damaged components.

21. Alarm Relays

Overview: The 1730 series has four mains-power rated alarm relays that can be programmed to
perform various functions. Each of these relays is independently controlled via the MCU. This test
individually energises each relay allowing the contacts to be tested using a DMM
Option Up/Down: select next/previous relay
Enter: no operation
As each relay is selected the relay solenoid is energised and the two terminals corresponding to that
relay should be shorted. Use a DMM to check continuity between the terminals and check that they
make a continuous circuit when the relay is energised and open circuit when the relay is de-energised.
If any of the relays fail to operate as expected, check the trace from the MCU to the transistorT10-T13
for the correct signal, then replace the relay and transistor as required.
22. LED Test – Lexan and Main PCB
Option Up/Down: select next/previous relay
Enter: no operation
This test is used to check that all the LEDs that are built into the lexan on the front of the case work, and
that the RS485 LED on the main PCB works. Cycling through each of the LEDs using the option keys
should enable each selected LED in turn to confirm that they work.
Option Up/Down: select next/previous LED
Enter: no operation
Document Revision 1.03 Page 13 of 16 Diagnostics Mode v1.08