DPS NetGuardian 832A, User Manual

Page: 99 / 107

94
A. In order for data port and craft port changes (including changes to the baud rate and word format) to
take effect, the NetGuardian must be rebooted. Whenever you make changes, remember to write
them to the NetGuardian's NVRAM so they will be saved when the unit is rebooted.
Q. The LAN link LED is green on my NetGuardian, but I can't poll it from my T/Mon.
A.
Some routers will not forward packets to an IP address until the MAC address of the destination
device has been registered on the router's Address Resolution Protocol (ARP) table. Enter the IP
address of your gateway and your T/Mon system to the ARP table.
Q. What do the terms "port," "address," "display" and "alarm point" mean?
A.
These terms refer to numbers that designate the location of a network alarm, from the most general
(a port to which several devices are connected) to the most specific (an individual alarm sensor).
Port: A number designating a serial port through which a monitoring device collects data.
Address: A number designating a device connected to a port.
Display: A number designating a logical group of 64 alarm points.
Alarm Point: A number designating a contact closure that is activated when an alarm condition
occurs. For example, an alarm point might represent a low oil sensor in a generator or an open/
close sensor in a door.
These terms originally referred only to physical things: actual ports, devices, and contact closures.
For the sake of consistency, port-address-display-alarm point terminology has been extended to
include purely logical elements: for example, the NetGuardian reports internal alarms on Port 99,
Address 1.
Q. What characteristics of an alarm point can be configured through software? For instance,
can point 4 be used to sense an active-low signal, or point 5 to sense a level or a edge?
A. The NetGuardian's standard configuration is for all alarm points to be level-sensed. You cannot use
configuration software to convert alarm points to TTL (edge-sensed) operation. TTL alarm points
are a hardware option that must be specified when you order your NetGuardian. Ordering TTL points
for your NetGuardian does not add to the cost of the unit What you can do with the configuration
software is change any alarm point from "Normal" to "Reversed" operation. Switching to Reversed
operation has different effects, depending on the kind of input connected to the alarm point:
·
If the alarm input generates an active-high signal, switching to Reversed operation means
the NetGuardian will declare an alarm in the absence of the active-high signal, creating the practical
equivalent of an active-low alarm.
·
If the alarm input generates an active-low signal, switching to Reversed operation means
the NetGuardian will declare an alarm in the absence of the active-low signal, creating the practical
equivalent of an active-high alarm.
·
If the alarm input is normally open, switching to Reversed operation converts it to a normally
closed alarm point.
·
If the alarm input is normally closed, switching to Reversed operation converts it to a normally
open alarm point.
Q. Every time my NetGuardian starts up, I have to reenter the date and time. How can I get the
NetGuardian to automatically maintain the date and time setting?
A. You have three options for keeping the correct time on your NetGuardian:
Real Time Clock Option: You can order your NetGuardian with the Real Time Clock hardware
option. Once it's set, the Real Time Clock will keep the correct date and time, regardless of reboots.
Network Time Protocol Synchronization: If your NetGuardian has Firmware Version 2.9F or later,
you can configure the unit to automatically synchronize to a Network Time Protocol (NTP) server.
·
To get the latest NetGuardian firmware, sign in to MyDPS at www.dpstelecom.com/mydps.
· For instructions on configuring your NetGuardian to use NTP synchronization, see your
NGEditG5 or NetGuardian Web Browser Interface user manual.