Legacy Systems

DM-2412
NT11
Dpal

PD4


DM-2412

Introduction

DM 2412

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.

Overview

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).

Characteristics of 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.
  • 8 Digital inputs
  • 8 Digital Outputs
  • 4 Analogue Outputs that provide a control voltage of between 0 and 2.5
    volts (in 256 steps)
  • 4 Analogue Inputs, accepting a voltage range of 0 to 5 volts
  • RS232 monitoring and configuration port
  • RS232 communications interface to a radio modem
  • Configuration of inputs to be normally open or normally closed
     

Operational Functionality


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.

Technical Description


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.
  • Single supply operation - +9 to +30VDC
  • 8-bit micro controller with the following features;                                                                                                   32K*8 bit RAM
    32K*8 bit EPROM
    512 bytes EEPROM
    CPU Watch-dog and power monitor
  • Current - Outputs Unloaded 30mA Typical Outputs Loaded 500mA Typical
  • Approx Size. -  W-170mm * D-150mm * H-25mm
  • Approx Weight - <12oz
  • RS232 Interface - 9-way D-Type front panel Baud rate - up to 38K4
  • Network Interface - 15-way D-Type rear panel mounted FFSK Baud rate - 1200/2400/4800
  • Analogue I/O - 15 way D-Type front panel mounted
  • 4 Analogue Inputs (0-5 VDC) 8 bit resolution
  • 4 Analogue outputs(0-2.5V) 8 bit resolution
  • Digital I/O - 25-way D-Type front panel mounted 4 opto isolated digital inputs Parallel Interface 22 bits 0-5V CMOS compatible I/O or optionally open collector outputs.





NT11

Introduction

NHDS Local Monitor NT11

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.

Overview

The basic NT-11 unit has the following facilities when used in a typical system. Customer specific options can be catered for in
most cases.

  • 8 Digital Inputs
  • 8 Digital Outputs
  • 2 Analogue Outputs that provide a control voltage of between 0 and 2.5 volts (in 256 steps)
  • 4 Analogue Inputs, accepting a voltage range of 0 to 5 volts
  • RS232 monitoring and configuration port
  • RS232 communications interface to a radio modem
  • 4 Opto-isolated inputs (isolation to 3KV)
  • Configuration of inputs to be normally open or normally closed

Operational Functionality

There are two main functions of the NT-11.

Modem: The NT-11 provides a user friendly interface to public radio data 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 NT-11 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 or via
GSM cellular radio data pads by the NHDS host terminal. The terminal can be configured to routinely poll NT-11 units for status
information and access the units data under operator selection. The unit can be programmed to report by exception, automatically updating the AMAC terminal with status information of its I/O under fault conditions, including programmable hysteresis.

Technical Description

Connection 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
  • Single supply operation - +9 to +15VDC
  • 8-bit micro controller with the following features
    32K*8 bit RAM
    32K*8 bit EPROM
    512 bytes EEPROM
    CPU Watch-dog and power monitor
  • Current - Outputs Unloaded 30mA Typical Outputs loaded 500mA Typical
  • Approx Size - W-170mm * D-150mm * H-25mm
  • Approx Weight - <12oz
  • RS232 Interface - 9-way D-Type front panel Baud rate - up to 38K4
  • Network Interface - 15-way D-Type rear panel mounted Baud rate - up to 19K2
  • Analogue I/O - 4 Analogue Inputs (0-5 VDC) 8 bit resolution 2 Analogue outputs(0-2.5V) 8 bit resolution
  • Digital I/O - 25-way D-Type front panel mounted 4 Opto isolated Inputs (Isolation to 3KV) Parallel Interface22 bits 0-5V CMOS compatible I/O or optionally open collector outputs


Dpal

Introduction                                                                        

The 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.

Description

The alarm interface unit enables both analogue and digital inputs to be monitored at all times.
Analogue And Digital Monitoring DPAL System

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.

Operation

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 the message.

The network, once accessed, will then transmit a message to the designated pager user or phone. The message can be a coded numeric message or, preferably, a full alpha-numeric text message, giving details of the alarm condition with a site address if more than one outstation is being monitored. The message will contain details of digital alarms or analogue levels exceeding (or dropping below) pre-set levels. Loss of mains supply to the monitoring unit will also cause a message to be transmitted.

This provides users with great flexibility, simplicity of working and a very cost effective solution to remote site monitoring.

If desired, the DPAL unit can be configured to send regular check messages to ensure continuing operation. The DPAL works on most paging networks and can be programmed to operate with your existing display pager, or a paging unit can be provided as a complete package with the DPAL outstation unit.

Technical Parameters

The 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.
  • Power input 240 volts AC  
  • DC power input option 12 VDC
  • External aerial connection via glanded cable entry
  • Internal RS232 interface
  • External alarm inputs via cable gland to 16 way tag strip
  • 8 digital inputs (CMOS compatible)
  • 4 analogue inputs (0-5Volt linear, 8 bit A/D resolution)
  • 4 opto isolated inputs (isolation to 50V)
  • Current consumption (non active) 30mA typical

Pods - PD4

INTRODUCTION

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.

The schematic below shows how the elements of the PD4 System fit together

NHDS PD4

One of the core objectives in designing the PD4 System was to allow customers to install, commission and maintain their own
entry level SCADA system without the need for expensive equipment, specialist knowledge or expensive training. A truly entry
level system would need to be 'delivered in a box' with 'how to' documentation.

Application

The PD4 Remote Site Monitor is the "sharp end" of the system. Each PD4 unit monitors the status of equipment and "reports by
exception" user defined alarm conditions to the Host Terminal via the GSM network. Output contacts in the PD4 unit allow remote
control of plant from the Host Terminal. The built in sealed lead acid battery and charger allow continuous operation during power supply interruptions.

Suitable applications could be the monitoring of any site where equipment status needs to be monitored, examples include:

  • Circuit Breakers in HV/MV substations
  • AC supplies to pumps, fans and motors
  • Door or gate positions
  • Pressure, temperature, humidity sensors
  • Any other remote/unmanned equipment

When fitted with output relay contacts, the Host Terminal operator can send control commands to the PD4 to operate remote
equipment such as fans, power supplies, lighting or circuit breakers etc.

PD4 Features:

  • Wall mounting IP54 polycarbonate casing
  • LCD display
  • Test buttons 
  • I/O
  • 3 x 240Vac or 110Vac monitoring
  • 8 digital inputs, software configurable as NO/NC and pulse/latching
  • 4 analogue inputs, 8 bit resolution, configurable high and low alarm thresholds
  • 3 relay outputs, steady state or pulsed

Communications

  • 900 GSM modem with antenna, 1800 and 1900 frequency options
  • Alternative option for PSTN (telephone land line)
  • Alternative option for PAKNET radio 
  • Protocol options include DNPS or proprietary

Power Supply

  • Auxiliary AC supply charges 6V Cyclon lead acid battery - gives 8 hours standby
  • Low battery volts alarm call function
  • Alternative for 24V dc (replaces the battery)

OPERATION

The PD4 unit uses a GSM modem to communicate with the Host Terminal. The GSM network provides links to standard land line
networks (just as you can make a voice call from your office to your cell phone and vice versa). The Host Terminal can have a standard PSTN land line modem and connection.

Conventional approaches to SCADA would typically use leased lines, point-to-point radio or trunked radio solutions. GSM is far easier to use and maintain as well as being much lower in cost than any of these systems.

GSM networks are already widely available across all continents and in most countries. Often there is a choice of GSM provider and, with the competition for voice users, the coverage and cost of use of GSM is making the technology more and more appealing. Conventional GSM data speeds of 9600baud mean that a PD4 transfers data to the Host Terminal in a matter of a few seconds.

You can configure the PD4 unit to send alarms to mobile phones as SMS Text Messages as well as to the Host Terminal. The
standard PD4 is supplied with a GSM modem built in. In order for the PD4 to work correctly all you need to confirm is:

Is there GSM coverage (there may be coverage from more than one GSM Network)?
Is "data" service available on the GSM Network?
If more than one possible network provider, which offers the best signal strength/cost of use?
Which frequency does the network operate on (900/1800/1900 MHz)?

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 Terminal

The 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:
  • Pentium PC running Windows 95/98/NT/XP/2000  
  • The PD4 Host Application software (from NHDS)
  • GSM modem(s) and/or PSTN (telephone line) modem(s)

The Host Application is a bespoke software program written in C++ which provides the user friendly intuitive MMI for the PD4
System. The Host Application offers the following main facilities:

  • Alarm Screen listing sites with current alarms
  • Site Display showing the status of equipment monitored by individual PD4 units
  • Archived alarms and event data with a variety of on screen search criteria
  • Answers incoming calls from PD4 units and updates displays and logs data
  • Polls PD4 sites to request status
  • Reprogram operational settings
  • Can simultaneously communicate with up to 16 remote PD4 units
  • Stores database records for PD4 site locations and operational settings
  • Flexibility to customise the alarms screens and database fields
  • Host Terminal Operational Status screen
  • Export data to other file formats
  • Can forward alarms/status messages directly to mobile phones/pagers as SMS text messages

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.

Click here to view the following PDF  :: PD4 Fact Sheet
We also have the following available ::  PD4 Configuration Kit    PD4 Training