Barnett Engineering ProTalk Cv3, Installation & Operation Manual, Page: 9 / 50

INSTALLATION PAGE 5
Wiring Your Inputs
Connections
The Cv3 has ten inputs for connection to customer alarm signals. Each
input can be independently programmed to accept either a digital or analog
signal. Refer to Figure 1 for details of the connector pinouts.
Contacts and Other Digital Alarm Inputs
When programmed for digital operation, the high (or open) state is
provided by a switched internal pullup resistor connected to a +5 volt
source. The low state is when the input voltage is below +2 volts. For most
applications, this is done by a closure to ground using either a relay
contact or an open collector/drain transistor. A voltage source can be used
for a digital alarm provided it can go below the +2 volt threshold and sink
1 mA. A voltage signal of up to +36 volts can be used without damaging
the input. Do not connect AC voltage sources of any type to the inputs.
For digital operation, connect the signal to the single terminal for inputs 1
through 6 and either the + or – terminal for inputs 7 through 10. Technical
drawings have been provided on page 41 for your reference.
In addition to the standard detection of an alarm state at the input, a
digitally formatted input can also be configured as a watchdog type of
alarm, or as non-alarm types: totalizer, accumulator or pulse width. A
watchdog alarm type requires a periodic refresh signal to prevent an alarm
condition; a totalizer type counts the changes at the input; an accumulator
stores the total time that the input is active and a pulse width measures the
duration of an active input. These three formats do not generate alarms and
must be interrogated to recover the reading.
Each change to a totalizer or accumulator count is stored in non-volatile
memory. If a power loss or system restart occurs, the stored count will be
recovered from memory and the count will continue without interruption.
Note that, in the event of a power loss, any activity that occurred during
the outage will not be recorded.
A digital input can also be alternatively programmed to perform one of the
three Special Purpose functions: local acknowledge, shift select or shift
Figure 1 Alarm Input Connections