Configuring Analogs - DPS Telecom NetGuardian 420 Hardware User Manual

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13.3.12 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
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.).
6. In the box below the abbreviated native unit setting enter the native unit amount that corresponds to the
minimum output entered in the previous step.
7. Set (VDC) to the maximum output (in volts DC) of the analog device being configured.
Reference 2
8. In the box next to
VDC
Fahrenheit, etc.).
9. In the box below the abbreviated native unit setting enter the native unit amount that corresponds to the
maximum output entered in the previous step.
10. Enter the Point Group ID designated for each alarm level (MjU = Major Under, MnU = Minor Under, MjO =
Major Over, MnO = Minor Under).
11. Click the
Submit Data
12. Follow these steps for each analog channel being configured.
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
enter an abbreviation for the native units (e.g. RH for relative humidity, F for °
button to save the configuration settings.