Advantech Adam 4000 Series User Manual page 37

Open Thermocouple Detection and Input Surge Protection (ADAM-4011D only)
The ADAM-4011D provides an open thermocouple detection function. Users can use
a simple command to detect whether the thermocouple is opened or closed. The
module also provides surge protection on its input channel. Internal high-speed tran-
sient suppressor on its input channel protects the module from dangerous spikes and
voltages.
Front Panel LED Indicator (ADAM-4011D only)
The 4½ digits LED display on the back of the ADAM-4011D lets you monitor the pro-
cess readings right at their source. The module displays readings in a wide variety of
formats as well as high-low alarm messages. The ADAM-4011D offers flexibility, easy
installation, and direct availability of process data. For critical process monitoring, this
module is the ideal choice.
Digital Input/Output
The ADAM-4011/4011D Thermocouple Input Modules also contain two digital outputs
and one digital input. Outputs are open-collector transistor switches that may be con-
trolled by the host computer. They can control solid-state relays, which may be used
to control 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 sig-
nal.
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 count will maintain at 65535 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
state. 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 if the input value returns within the limits. An
alarm in Latching mode can be turned OFF by giving 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 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 involvement of host computer.
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