Chapter 3
Chapter 3 I/O Modules
3-73
External Control (Gate mode)
Aside from the GND and counter terminal, each channel has a gate
terminal to connect to an external gate signal. The gate signal (high or
low) can trigger the counter from start or stop counting. The gate mode
can be among these three options, low, high or disabled (low means that
counting starts when the gate signal is low. It stops once the gate signal
becomes high)
Programmable Alarm Output
The ADAM-4080 module provides a configurable alarm for each
counter. The ADAM-4080D provides high and low alarm functions for
counter 0. When the counter reaches an alarm limit, it will trigger the
built-in digital output of machine ON/OFF control. The alarm limits
may be downloaded into the module's EEPROM by the host computer.
The initial count value of ADAM-4080 module's counter can be
configured in any values.
The alarm functions can be enabled or disabled remotely. When the
alarm functions are enabled, digital output channels are used to indicate
the alarm states. For ADAM-4080, digital output channel 0 equals to
the alarm state of counter 0, and digital output channel 1 equals to the
alarm state of counter 1. For ADAM-4080D, digital output channel 0
equals to the low alarm state of counter 0, and digital output channel 1
equals to the high alarm state of counter 0.
Every A/D conversion will be followed by a comparison of alarm
limits. If the input value exceeds one of these limits, the corresponding
alarm state is set to ON.
There are two alarm mode options, momentary and latching, for
ADAM-4080D. If the alarm is in latching mode, the alarm will stay on
even when the input value returns within the limits. An alarm in
latching mode can be turned off by issuing a Clear Alarm command
from the host computer. A latching alarm is cleared by the module
when the opposite alarm is set. For example, the alarm is in latching
mode and the high alarm is then turned ON. When the module receives
a value that is lower than the low alarm limit, it will clear the high
alarm and turn the low alarm ON.
When the alarm is in Momentary mode, the alarm will be turned
OFF as soon as the input value returns within the limits.
The arrangement of coupling high and low alarm states with digital
output lines may be utilized to build ON/OFF controllers that can
operate without the host computer involvement.