AddMe II features 16
universal inputs with changeable network variable types. The universal
inputs are context sensitive. When confi gured as an analog
input, the continuously self-calibrating sigma-delta converter produces
15-bit resolution with high noise immunity. When confi gured
as a discrete input, the converter switches to 8-bit resolution
at 128 samples per second for fast response.
Network variables for the analog I/O points may be confi gured for
any scalar LonMark SNVT, fi xed point or fl oating point. In addition,
analog (universal) inputs may be confi gured to SNVT_switch
with the on threshold programmed via the translation tables. Translation
tables allow linearization of type II or type III thermistors
or other nonlinear sensors. Both 3K and 10K thermistors can be
connected directly to analog inputs. A 24VDC excitation output is
also provided for sourcing up to sixteen 20mA sensor loops.
Only LonMark standard variable types and confi guration properties
are used. The standard LonMark Object plug-in, or LonMaker
browser, can be used to do all necessary confi guration. Send times
for network traffi c throttling and heartbeat, send on delta, object
override, etc., are all supported per LonMark standards.
The analog sensor inputs include the full complement of LonMark
alarm features. Each input has two high and two low alarm limits
with hysteresis. Alarms are reported via the node object nvoAlarm2,
and also appear in the sensor’s object status.
