Adam-4012 Analog Input Module - Advantech Adam 4000 Series User Manual

3.3

ADAM-4012 Analog Input Module

The ADAM-4012 Analog Input Modules use a microprocessor controlled integrating
A/D converter to convert sensor voltage or current signals into digital data. The digital
data are then translated into either two's complement hexadecimal format or percent-
age of full-scale range (FSR) according to the module's configuration. When
prompted by the host computer, the data are sent through a standard RS-485 inter-
face.
The ADAM-4012 Analog Input Modules offer signal conditioning, A/D conversion,
ranging, and RS-485 digital communication functions. They protect your equipment
from power surges at the ground terminal by providing opto-isolation of the A/D input
and up to 3000 V transformer based isolation.
DC
Digital Inputs/Outputs
The ADAM-4012 also contains two digital outputs and one digital input. Outputs are
open-collector transistor switches that may be controlled by the host computer. They
can control solid-state relays, which can be applied to heaters, pumps, and other
electrical powered equipment. The digital inputs may be read by the host computer
and used to sense the state of a remote digital signal.
Event counting
The event counter is connected to the Digital Input channel and can be used to keep
track of the total amount of external low-speed pulses. Its accumulated maximal
count is 65535. The number 65535 is held even if the actual number of events
exceeds 65535. The counter can be read or reset to zero by the host computer.
Since the Event counter's data are not stored in EEPROM, the event counter is
cleared and set to zero after every reset or start up of the analog input module.
Alarm signaling
Analog input modules include High and Low alarm functions. High and Low alarm
limits may be downloaded into the module's EEPROM by the host computer.
The alarm functions can be enabled or disabled remotely. When the alarm function is
enabled, both Digital Output channels are used to indicate the High and Low alarm
states. Digital Output channel 1 (DO1) equals to High alarm state, and Digital Output
channel 0 (DO0) equals to Low alarm state. The High and Low alarm states can be
read at any time by the host computer.
Every A/D conversion will be followed by a comparison with the High and Low limit.
When the input value exceeds one of these limits, the High or Low alarm state is set
to ON.
There are two alarm mode options, Momentary and Latching. If the alarm is in Latch-
ing mode, the alarm will stay on even when the input value returns within the limits. It
can also 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. 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 arrange-
ment of coupling High and Low alarm states with Digital Output lines may be utilized
to build ON/OFF controllers that can operate without involving the host computer.
29 ADAM-4000 Series User Manual