Quartech 9605, Product Manual

Section 2: Operating the 9605

Page 5

PM9605 Revision 1, 9605 Version 36.1.1

The register bits may be used as normally open or
normally closed contacts within the PLC application
program just as input bits would be. The effect the
9605's switches have on their assigned register bits
depends on how the switch is configured.

If the configure bit is zero (0) the corresponding
switch will operate as a momentary push-button.  If
a configure bit is one (1) the corresponding switch
will operate as a push on/ push off selector switch.

0 = Momentary (push-button) switch.
1 = Selector switch (push on / push off).

2.6  Watchdog Timer (Option)

The 9605 offers the option to create a communication watchdog timer in the SLC-500's application program.  It will
work like this:  You must program a free running timer into the application program; 
set a preset value of about ten (10) seconds for most applications.  Then give the 9605 the address of this timer,
by entering the file number and the element number during the setup of the 9605 (see section 3).  The 9605 will
write a value of zero (0) to the accumulator of this timer on a regular and continuous basis; therefore the timer will
not reach its preset value, so long as the 9605 is communicating with the PLC.  If the watchdog timer ever times-
out, you will know that communication has been interrupted, and you can take whatever action is appropriate.

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 The watchdog timer function is optional.  It can only be implemented if a valid timer 

    address is entered properly during the setup process.  If the watchdog timer element 
    does not exist, or if the entered address is not valid, the 9605 will signal an error.

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 The watchdog timer can be disabled by simply entering a value of zero (0) for the 

    watchdog file and element address while the 9605 is in setup mode.

In most applications the watchdog timer function will be very important.  Keep in mind that the PLC's application
program will be making decisions based on the status of the bits in the Dialogue File.  If the 9605 cannot
communicate with the SLC-500, the data in the Dialogue File may not be valid.