The DM-2412 is a compact, ruggedised, microprocessor based mobile data modem unit, combining the ability to transmit FFSK data with the provision for a local monitor / control facility on standard PMR radio channels.
The DM-2412 has many of the remote telemetry I/O features of the NT-11, the main difference being that the DM-2412 manages and controls transmission of FFSK data over standard voice radio channels at the highest practical baud rate (1200/2400/4800 bits/second).
the unit and radio interface are held in non volatile memory. A
comprehensive user friendly program interface is available through a
standard VT100(ANSI) terminal interface (as provided by most
communications packages such as Windows HyperTerminal).
The DM-2412 transmits data in packets and makes use of a subset of the MPT1327 trunked radio protocol. The unit has two modes of operation, non prescribed data mode and short data message mode.
In non prescribed mode, a virtual circuit is opened between two DM-2412 units and block data transfer takes place. The unit makes use of a Go Back-N ARQ protocol with 4 Bit error detection and 4 Bit error correction.
In short data message mode the unit will transmit and accept real time status and control information. This is particularly useful in telemetry applications where the channel usage is restricted and multiple units require access to a single channel. The unit will converse directly with all trunked radio units capable of accepting and transmitting short data messages, thus making use of excess capacity on the control channel of MPT1327 networks.
The basic DM-2412 unit has the following facilities. Customer specific options can be catered for in most cases.
There are two main functions of the DM-2412: Modem: The DM-2412 provides a user friendly interface to PMR networks by buffering data from custom computer terminals, providing a pre-processing data facility for economy terminals and allowing custom data despatching systems to be more easily implemented.
The DM-2412 provides a store and forward facility to serially connected mobile terminals.
Outstation: Configurable Analogue and Digital inputs and outputs can be remotely controlled over a public data network by the NHDS host terminal. The terminal can be configured to routinely poll DM-2412 units for status information and access the units data under operator selection. The unit can be programmed to call in by exception, i.e. automatically update the AMAC terminal with status information of its I/O under fault conditions, including programmable hysteresis.
Connection to the DM-2412 is made via D type connectors. There are 3 D type connectors on the front panel and one connector located at the rear of the NT-11.
The NT-11 is a compact, ruggedised, microprocessor based mobile data modem unit, combining the ability to transmit computer data with the provision for a local monitor / control facility on public radio data networks and via GSM cellular radio pads.
The basic NT-11 unit has the following
facilities when used in a typical system. Customer specific options can be
catered for in
There are two main
functions of the NT-11.
Technical DescriptionConnection to the NT-11 is made via D type connectors. There are 3 D type connectors on the front panel and one connector located at the rear of the NT-11
IntroductionThe ability to page on duty staff when an alarm condition occurs is required by many diverse organisations. The alarm location is often isolated or temporary with no telephone line and sometimes no mains power. The security requirement is still there with high-value property or important conditions that must be monitored at all times. The DPAL system meets all these requirements and more.
DescriptionThe alarm interface unit enables both analogue and digital inputs to be monitored at all times.
|The unit is microprocessor
controlled and will work with a standard Paknet radio modem or cellular
radio pad (GSM). The equipment is contained in a rugged wall mounted
enclosure. There are 8 digital alarm inputs together with 4 analogue
inputs which may be connected to a variety of sensors for monitoring water
level, temperature, voltage, flow rate, etc. The unit is normally powered
from an AC mains transformer, but also contains a rechargeable battery to
enable continuous use. Solar power inputs can be provided as an option.
The unit can be located at any isolated location which requires monitoring.
The unit, on activation, accesses the paging network via the Paknet radio modem and sends an alarm message to the designated pager directly, not via a central bureau, or calls a GSM mobile on the same network with an SMS message.
An optional central monitoring station at a main office can be provided if several outstations are being monitored. This will provide a central log of all incidents and the ability to check that the necessary action has been taken.
On the activation of an alarm the DPAL switches on the Paknet radio
modem, which is normally powered off to keep current consumption very low
in a non-active state, and sends a digital message to the selected pager
network (or SMS message to a GSM mobile phone). If for any reason access
is not obtained then a retry mechanism is invoked to ensure delivery of
Technical ParametersThe DPAL program characteristics are held in non-volatile memory. Parameters are configured via an RS232 interface from a standard VT100 (ANSI) terminal, or a personal computer running a suitable communications program.
The "PD4 System" was designed specifically as an Entry Level
SCADA System. Made up of any number of PD4 units (monitoring inputs from
your production processes, plant or simple status inputs) communicating
over air using mobile phone technology to a central PC used to display
incoming alarms and status changes as well as for archiving and exporting
data. Alternatively, PD4's can report status as SMS text messages directly
to mobile phones or pagers.
One of the core objectives in designing the PD4 System was to allow
customers to install, commission and maintain their own
The PD4 Remote Site Monitor is the "sharp end" of the system.
Each PD4 unit monitors the status of equipment and "reports by
When fitted with output relay contacts, the Host Terminal operator can
send control commands to the PD4 to operate remote
The PD4 unit uses a GSM modem to communicate with the Host Terminal.
The GSM network provides links to standard land line
Is there GSM coverage (there may be coverage from more than one GSM
To allow the PD4 access to the GSM Network, the GSM modem in the PD4 must be fitted with a SIM card. This SIM card is issued and then "activated" by the GSM Network provider. The SIM card is not supplied as part of the PD4 unit.
Host TerminalThe PD4 Host Terminal is the focal point of the PD4 system. It is simple to install and use, with a variety of useful features to
enable quick response to alarm conditions detected at remote sites. The specification is as follows:
The Host Application is a bespoke
software program written in C++ which provides the user friendly intuitive
MMI for the PD4
We provide a "Training Version" of the Host Application to allow users to familiarise themselves with the system. You can simulate incoming alarms, create new remote sites, reprogram operational settings, export data - in short, all the functions of a live system but in a dummy environment.
DNP3 Communications Protocol. In order to maintain upward compatibility with "HIGH END" SCADA systems, NHDS can provide a DNP3 compliant version of the PD4, thus allowing integration into standard SCADA system.