Configuring Analogs - DPS Telecom NetGuardian 420 Web User Manual

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4.3.12 Configuring Analogs

Each of the NetGuardian 420's analog channels must be individually configured to monitor data. The ADCs
(analog to digital converters) support a range of –70 to 94 VDC. There are four alarm trip points (thresholds) in
ascending order: major under, minor under, minor over, and major over. You can choose the values for each of the
thresholds on all channels. As with the other alarms, you can designate whether or not to send an SNMP trap
when a threshold is crossed. The primary/secondary pager used to report the alarm is also set here. The thresholds
must be set from
Under
–10, –5, 5 and 10 corresponding respectively to major under, minor under, minor over and major over is valid.
The analog alarms are set to measure voltage by default and the thresholds are reported as "native units." For
example, you may set Channel 3 to measure outside temperature. If you were using a sensor with a measurable
temperature range between –4° to 167° Fahrenheit (–20° to 75° Celsius). The voltage for that channel varies
between 1 and 5 VDC for that sensor, which is to be reported as ° Fahrenheit (native units) where 1 volt
represents –4° Fahrenheit and 5 volts represents 167° Fahrenheit.
To change any one analog alarm to measure current instead, a dip switch setting must be changed. Refer to the
NetGuardian hardware user manual for details on jumper locations and positions. The jumper inserts a 250 ohm
shunt resistor across the input to convert the sensors current output to volts. Use ohms law to find the voltage drop
across the 250 ohm shunt resistor (multiply the current by the resistance 250 ohms). Please refer to the operation
manual for your sensor to determine any other conversion factors. This will allow you to correctly set the
thresholds for and
over under
The Analog Parameters can be viewed and changed from the Analogs screen
NOTE: To configure the gauge type, select the link in the 'Unit' column. From here you can select which gauge
(or none at all) you want displayed under Base Analogs in Monitor Mode.
1. From the menu click on the
Edit
2. In the field enter a description for each analog channel being utilized.
Description
3. Under the column, click on the abbreviated units link (e.g VDC, RH, F, etc.).
Unit
4. Set (VDC) to the minimum output (in volts DC) of the analog device being configured.
Reference 1
5. In the box next to
VDC
native units (e.g. RH for relative humidity, F for ° Fahrenheit, etc.).
to in either ascending or descending potential (or current) order. Thus the settings of
Over
conditions.
link.
Analogs
(the space may already contain the abbreviation VDC) enter an abbreviation for the