Terminal Components

Standard Terminal.
The 19", 3U high terminal houses circuit cards and the Monitor module that comprise the DEWAR DM1200 terminal All wiring is to the rear terminals which are fitted with supplied mating connectors. This allows pre-wiring prior to actual installation of the terminal. This simplifies both installation and maintenance. A two level back plane arrangement separates the functions of field connections and internal signals thus protecting the equipment from accidental damage and interference.

All active components are mounted on keyed circuit cards that are accessible from the front of the terminal.

Reversible mounting brackets provide for either flush mounting in the user's rack or where depth is restricted, semi projection mounting. Provision is made for the user to fit a ‘Tally Plate’ to the top of the terminal.

Power Supply
This module isolates the users communication battery from the system's internal rails to 5KV. It also contains the ‘common alarm’ relay isolated to 5KV. The Power supply is provided in two versions, one for nominal battery voltages from 20 to 60 VDC, the other for 90 to 320 VDC.

Inrush protection and ripple filtering ensure minimum disturbance to the user's battery supply.

G703 Digital Processor
This module performs the real time tasks required by the system for 64kB G703 communications. It uses a Digital Signal Processor (DSP). The tasks include:

• Communications with remote terminal in co-directional (4 wire) or contra directional (8 wire).
• Debounce the trip-input signal from the field.
• Validity tests on received signal from the remote terminal.
• Timed extensions on the trip command.
• Self testing of the command IO hardware.
• Provide a supervisory data path for monitor to monitor communication.

RS422 Digital Processor
This module performs the real time tasks required by the system for 9 kB to 80 kB RS422 communications. This can be wired to RS449 or RS530 or other connectors on interfacing equipment. It uses a Digital Signal Processor (DSP). The tasks include:

• Communications with remote terminal (8 wire).
• Debounce the trip-input signal from the field.
• Validity tests on received signal from the remote terminal.
• Timed extensions on the trip command.
• Self testing of the command IO hardware.
• Provide a supervisory data path for monitor to monitor communication.
• Provide transmitter and receiver communications rate compensation for event logging.

VF Analogue (Tones) Processor.
This module performs the real time tasks required by the system for voice frequency communication. It uses a microprocessor and switched capacitor filter technology. The tasks include:

• two FSK transmitters and two FSK receivers.
• communications with remote terminal.
• Debounce the trip input signal from the field.
• frequency analysis on the received signal from the remote terminal.
• timing functions related to noise and command security.
• timed extensions on the trip command.
• self testing of the command hardware.
• provide supervisory data for monitor to monitor communication.
• Provide Loss of Guard (LoG) detection.

Trip I/O.
This module provides 5000 volt isolation barrier between the command field wiring and rest of the system. The command input voltage is selected by the user for command battery voltages between 24V and 240V. Three sets of command output ‘N.O. contacts’ are provided. Dual path circuitry for both input and output are provided to ensure that a component failure cannot result in a false trip.

Up to Four Trip I/O cards may be fitted to the terminal for G703 and RS422 communication and up to two trip IO cards fitted for VF communications.

Monitor Module.
The Monitor module provides user interface to the terminal and provides extensive alarm reporting, monitoring and configuration facilities. To facilitate quick setups, built in default setup tables can be used for fast response (blocking), medium security and response (permissive underreach/overreach) and high security (intertripping) applications

The operator interface consists of an 4 line by 20 character, back-lit LCD display menu and membrane keypad switches. Terminal configuration is achieved by interfacing with the display menus and setting required parameters. Scrolling through the menus allow information about the configuration and operational history of the system to be observed. Attention is drawn to alarm or command activity by the flashing of the display back light. The Monitor Module interface with one or two relay cards, providing a maximum of 16 single changeover contacts, for the external signalling of alarm activity.

The Monitor Module also provides communication between near and far end terminals, via the processors, for status information and interlocking during manual trip testing.

Typical of the items found in the menus are;

Supervisory Functions

• local terminal status,
• remote terminal status,
• processor control,
• identity checking,
• power supply checking.
• alarm processing,
• alarm relay control,
• set-up menus,
• logs for command and alarm event history,
• local area network between local terminals
• answer only modem interface to the public telephone network,

Communication Mode

• Identification of G703, RS422 or VF processor card,
• trip and guard frequencies over VF link,
• Co or contra-directional over G703 link,
• master / slave over G703 and RS422 link,
• Clock inversions over RS422 link.
• Local loop back for testing.
• Violation/No violation over G703 setting

Trip I/O configuration

• cards fitted, circuits used, series contact settings.

Security level

• G703 and RS422. Count of valid frames.
• Voice Frequency (Tone) Qualifying time, inhibit onset time, correlation time and inhibit extend time.
• Voice Frequency (Tone) Transmitter input and receiver output options.

Trip IO Timing

• input debounce, input and output extend times, forced cut-off time, hold-off time.

Alarms

• allocation of relays, on-set time delay, latching or non-latching action, relay alarm state.
• common alarm control

Trip Counter Reset

• all or specific counters.

Manual Trip Test

• request permission, grant permission, select trip circuit

The Monitor has a RS232 port enabling communication with external devices for setup and information.

Access to certain functions can be restricted by pass codes or left set to 0000 for unrestricted access if so desired.

Trip IO Timing

There are five programmable timing functions associated with each trip command:

Debounce: 0 to 99 msec. Delay between application of trip input and acceptance by the system. Prime purpose is to make system immune from input spikes but can also be used to delay transmission. Specifying a value of zero will remove the function.

Input extend: 0 to 990 msec. Stretches trip sent in cases where trip input may be too short to give adequate dependability. Specifying a value of zero will remove the function.

Output extend: 0 to 990 msec. Stretches trip output so that under poor conditions, a minimum duration of the trip output can be guaranteed. Specifying a value of zero will remove the function.

Cut-off time: 0 to 200 sec. Forces the command output to be terminated if held too long. Specifying a value of zero will remove the function.

Hold-off time: 0 to 200 sec. Following the end of a trip output (normal or cut-off), a new trip output cannot be established until the expiration of the hold-off time. Specifying a value of zero will remove the function.

Log of Guard (LoG) Output.
The VF receivers can detect the absence of a tone in the FSK channel. The speed of detection and output is controlled by the inhibit onset timer setting (0-250msec) on each VF receiver channel. If dual channel receiver operation is used, both receivers detect LoG. The LoG is output from a second trip IO card.

Events.
An event in this context refers to trip, LoG or alarm activity. The flashing of the LCD display back lighting indicates that a change of the alarm, LoG or trip event has taken place. Selection of Trip Status or Alarm Status from the Information menu will identify the event. Events are stored in non-volatile memory and can be remotely accessed and down loaded for analyses. Information includes in chronological listing, description (with a reason where possible), date and time of event.

Component Failure.
Another source of insecurity is component failure. The DEWAR DM1200 has dual signal paths that commence after the trip input dropping resistors and continue right to the trip output terminals. These paths incorporate opto-isolators, microprocessor I/O ports, software functions and memory locations, code words and output transistors. The components used for the two paths do not share common packages and signal levels are complimentary. Both paths must operate to generate a trip, the fail-safe condition being guard.

Such redundancy is of limited value unless component failure can be detected. For this purpose the DEWAR DM1200 self test routines provide continuous automatic detection of failed components in the command signal path.

Terminal Identity.
The DEWAR DM1200 provides a facility to give security against the possibility of cross connection of communications bearers by checking the source identity of received signals on the G703, RS422 and VF communications channels. If identity checking is enabled, the Operations Menu pass codes of both terminals must match before command operation is enabled by the monitor modules.

ELECTRICAL CHARACTERISTICS.

Commands VF up to two
G703 up to four.

G703
Output (Transmitter) Conforms to CCITT / ITU. G.703. 64 Kbits/sec..
Input (Receiver) Conforms to CCITT / ITU. G.703. 64 Kbits/sec.
Nominal Impedance 120 W
Speed (‘Tac’) 1.5 msec. to 9 (+debounce) msec depending in user configuration.
Security (‘Puc’) from 1E-12 to 1E-3.
Dependability (‘Pmc’) from 1E-6 to 0.50.

RS422
Output (Transmitter) Conforms to RS422. 9 to 80 Kbits/sec..
Input (Receiver) Conforms to RS422. 9 to 80 Kbits/sec.
Nominal Impedance 100 W minimum
Speed (‘Tac’) 1.2 msec. to 56 (+debounce) msec depending in user configuration and rate.
Security (‘Puc’) from 1E-12 to 1E-3.
Dependability (‘Pmc’) from 1E-6 to 0.50.

Voice Frequency (Tone)
Guard and Command Frequencies Programmable, 300 Hz to 4095 Hz in 1 Hz steps
Shift Frequencies. Programmable, 20 to 500 Hz in 1 Hz steps
Speed (‘Tac’) 8 msec to 400 (+debounce) msec. depending on user configuration.
Security (‘Puc’) from 1E-6 to 0.5.
Dependability (‘Pmc’) from 1E-4 to 0.5.

VF Output (Transmitter) Balanced 2 wire.
Nominal impedance 600 W
Return loss Calculated >35dB
Nominal level -35 dBm to +3 dBm. Per channel.
Power Boosting 0 dB to ± 10 dB. On nominal level set.

VF Input (Receiver) Balanced 2 wire.
Nominal impedance 600 W
Return loss Calculated >35dB
Receiver sensitivity -40 dBm to +10 dBm per channel

GENERAL
Command Inputs
Number of inputs 1 for each command.
Nominal activation voltage 24, 32, 48, 110, 240Vdc
Operating voltage All -20% to +35% of nominal
External signalling Solid State Relay..
300ma / 250Vdc or 2 A / 120Vdc.
Polarity sensitive (DC)
Command signal extension 0 to 990 msec in 10 msec steps.
Debounce Time 0 to 99 msec
Consumption 40 ma across range 24 to 110 VDC
20 ma / 240 VDC
Insolation, 5KV DC

Command Outputs.
Type Three solid state N.O. relays with voltage free contact protected.
Maximum current 2 amp. 5 amp for 5 seconds.
Maximum voltage 300 VDC.
Insulation 5 KV DC.
Command transmission signalling Relay contact 2A / 50Vdc to 300ma / 300 VDC.
Hold off Time 0 to 200 sec.
Command signal extension 0 to 990 msec in 10 msec steps.

Test Devices Manual test. Safe, Live, Inputs only
All input/output & communication functions under
continuous test. Approximately 8 times/sec.

Local Setup and Supervision System Interface, 4 by 20 LCD and keypad
Setup checked before settings are saved/used.

Remote Setup and Supervision System Interface EIA RS-232C (DCE) or LAN (proprietary 2 wire duplex)
Uses "1200TALK" terminal program on PC or Laptop
300 to 56 Kbaud RS232
Advanced setup interface with dynamic setup checking.
Setup download and upload.
Event log download.
Status download.

Counters. 4 send and receive counters of 3 or 4 digits.

Power Supply 20 to 60 Vdc and 90 to 320 Vdc. (Ordering option.)

Dimensions 19" 3U high. Total depth 355 mm.
Flush or semi projection mounting.

Operating temperature -10 degree C to +55 degree C.
Relative humidity not greater than 95%

Programming Terminal. Fully user programmable from front panel Keypad / LCD interface
Fully user programmable from remote location.
Factory defaults for blocking, permissive and intertripping.
Factory set up to customer specifications if required.

Terminal Identification, programming/supervision. Yes

Features

The use of modern VLSI digital techniques has resulted in a compact unit with capabilities far exceeding those of previous models.

• Firmware control.
• Menu driven software control.
• Dual microprocessor architecture.
• All major system parameters under user control.
• Separate user pass-code entry to 1/ set up, 2/ maintenance 3/ operations menus.
• User programmable security and dependability to suit user application.
• Set up configuration stored in non-volatile EEPROM
• End to end supervisory link allows remote terminal identification, time locking, testing, etc.
• High speed 64Kbit/s communications; direct terminal to terminal or co-directional or contra-directional CCITT G703,RS422 digital link or extended CCITT G232 voice frequency processors.
• Input to Output utilises total dual path hardware and software redundancy (dual complimentary path) ensures that no single component failure can cause a trip.
• Continuous automatic self test (approx’ 8 times per second) and Manual test.
• Self diagnostics to component level
• 4 x 20 character LCD and keypad provides full set up and monitoring facilities.
• No internal trimpots or mechanical adjustments.
• No add on equipment purchases for programming or set up.
• Supervisory link allows remote terminal identification, time locking, testing, etc.
• An RS232 / RS485 LAN for remote supervision and set up via a PC or modem connection.
• Time stamping of command and alarm events.
• History of previous events with down load capability.
• Non volatile battery backed memory.
• Rechargeable backup battery, with inbuilt automatic charger.
• Common alarm relay, 2C/O on PSU.
• 1 or 2 Alarm Relay cards (8 by 1C/O relays per card) can be fitted. (16 relays total capability)
• The G703 and RS422 processor modules can operate 1, 2, 3 or 4 trip IO cards giving 1 to 4 independent trip command functions.
• The VF processor module has two FSK channels. These can be configured as a dual channel single command system requiring 1 trip IO card, as a single channel single command system requiring 1 trip IO card or as 2 channel 2 command system requiring 2 trip IO cards. A fast Loss of Guard (LoG) output can be selected for interface to trip breaker logic.
• Alarms can be logically "ORed" to any relay or to any adjacent pair of relays (ei to operate as a 2C/O). Also a common alarm relay, on the power supply card, can be programmed to operate with any alarm combination.
• Three separate command input voltage terminals 240VDC, 120VDC and a LOW voltage range. The LOW voltage can set to 24, 32 or 48VDC.
• Three normally open command output "contacts" per command channel. Two trip output ranges are available, 2amp 180VDC maximum or 0.5amp 320VDC maximum, as an ordering option.
• Two power supply ranges are available, 20 to 60VDC and 90 to 320VDC, as an ordering option.
• The DM1200 series of Dewar Teleprotection terminals are housed in a standard 3U by 19 inch rack. As the systems use the same terminal and support modules, changing the communications type is achieved by simply changing of the processor module. The software for G703, RS422 and VF is co-resident.
• Isolation, Impulse and HFD to IEC60384-1 and IEC255 standards..
• Checking the source identity of received signals on the G703, RS422 and VF communications channels