> One, project background
The city water supply dispatch supervisory system main goal is
solves the running water company to supply water various links test
point data acquisition and the monitoring. This system is
composed by the monitoring center and each water source test point,
each water source test point data acquisition terminal (RTU or PLC)
may monitor and gather the water level, the pressure, the current
capacity, the turbidity, Yu Lv, pumps the frequency and so on each
kind of data, uses for the control center and the department concerned
analysis and the decision-making, enhances the working efficiency,
guaranteed the water supply quality, satisfies increases production
day by day uses the water volume the demand.
The city water supply dispatcher needs to carry on the
management to each waterworks, including the running water company
control center, the water works divides controls central, the pipe
network pressurizing point and the water source monitoring station and
so on. The city water supply dispatch system generally includes:
The water department control center, many water works divide
control the center, many water works monitor the substation, many
water sources well monitoring station, many pipe networks pressurizing
point and many pipe networks measured presses the station.
The city water supply dispatch supervisory system may carry on
the surveillance and the control to the long-distance scene movement
equipment, realizes the pipeline pressure, the water current capacity
data transfer and the valve switch automatic control, reduced the
failure rate and enhanced to the system reaction time. Is
advantageous for the prompt rapid understanding and the control
far-end pipeline and the valve, the low failure rate and the overhaul
time, reduces cuts off the water supply the number of times.
Various water sources test point data acquisition terminal may
automatically gather pipeline data and so on pressure, water current
capacity real-time data and switch condition, the intelligence
transmission running water company's monitoring center, the monitoring
center through to the data which transmits carries on the analysis,
may find the place which crashes, thus when a far-end appears the
breakdown, can solve the problem in the shortest time, restores the
water supply, raised the whole service level, thus has realized the
city water supply information, the modernization.
At present, in the running water water supply dispatch
supervisory system uses the data communication may simply divide into
wired and the wireless two big kinds, line-wire communication mainly
includes erects the optical cable, the electric cable or rents the
telecommunication telephone line, X.25, DDN, ADSL and so on, but
wireless includes the ultra-short wave communication, the wide
frequency correspondence, the satellite communication, GSM the short
note /GPRS correspondence and so on.
In city water supply dispatch supervisory system, because
various pipe networks 监控�distribution scope broad, the quantity
many, is away from far, the individual spot also is situated remotely,
therefore erects the optical cable, lays down the electric cable
difficulty in a big way, is not realistic, rents the special-purpose
telephone line to the telecommunication department to have to apply
for very many telephone lines, moreover some 监控�lines arrive
with difficulty, when uses the telephone channel needs to wait for
long telephone digit dialing process, speed slow, the operation cost
higher, in brief supervisory system uses the line-wire communication
way construction cycle long, the work difficulty big, the operating
cost is high, inconveniences to the large-scale use; Compares
with it, the wireless mailing address appears extremely nimbly, it has
the investment few, the construction cycle short, the movement
maintenance is simple, the price compared to the higher merit.
In the supervisory system, the wireless mailing address mainly
includes: Ultrashort wave (230MHz) without line number
biography, wide frequency, satellite communication, GSM numeral
honeycomb communications system and so on, satellite communication
because the correspondence expense is expensive, only uses under some
special domains, has not been able to popularize; But wide
frequency communication although the speed is high, but only can
transmit in the apparent distance scope, the application also is
restricted. Uses the ultrashort wave number to pass on the
broadcasting station achievement to transmit the channel to have the
network nimbly, the expansion is easy, the service conveniently, the
operating cost low and so on the merit, but because the system work
also uses the ordinary indirect modulation to 230MHz the number to
pass on the broadcasting station, this creates the system the external
interference, the correspondence speed lowly, the error rate high, the
data transfer quantity not big, the signal cover scope is been easily
small and so on the shortcoming.
Second, plan choice
After the comparative analysis, we choose the GPRS
system which China moves to take the city water supply dispatch
supervisory system the data communication platform. At present,
the GSM network after telecommunication department's many years
construction, the cover scope unceasingly expands, has maturely become
maturely, stable, the reliable correspondence network, specially China
moves the GPRS data service which newly promotes.
The GSM/GPRS system may provide the macrozonality the wireless
IP connection. Constructs the running water water supply
dispatch supervisory system in the mobile communication company's GPRS
service platform, realizes the pipe network 监控�wireless data
transmission to have may fully use the existing network, reduces the
construction cycle, reduces the construction cost the merit, moreover
the equipment setup convenient, the maintenance is simple.
The GPRS wireless supervisory system has following
characteristic:
1st, good real-time response and handling ability.
Compares with the short news service, because GPRS has the
real-time on-line characteristic, the system does not have when
extends, the system can simultaneously real-time gather, process
many/all test points each kind of data, does not need the wheel to
patrol may the synchronized test point clock be possible the very good
satisfied system logarithm according to gathering and the transmission
timely request.
2nd, long-distance instrumentation equipment control:
Because uses the GPRS two-way transmission system, the
monitoring center may reverse realize to the instrumentation equipment
time adjusts, function and so on condition report, switch and all that
monitor, control.
3rd, construction cost low: But fully uses the existing
GSM network, the equipment setup namely puts through, when uses the
ultra-short wave communication needs fully to consider the scene
environment, but also needs to provide the antenna iron stand and so
on the appurtenance.
4th, installs the debugging to be simple, construction cycle
short: Uses the existing mature GSM network, when the system
investment movement basic does not need to debug, the installment is
simple and direct. Uses when the ultra-short wave communication
installs the debugging work load to be big, must first carry on the
scene signal test, the antenna iron stand erects, work and so on
antenna direction angle debugging.
1st, the cover scope is broad. Constructs the water supply
dispatch supervisory system request data communication cover scope to
be broad, expands accommodates unlimitedly, turns on the place
unlimitedly, can satisfy the mountainous area, the villages and towns
and the cross area turns on the demand.
Because pipe network 监控�quantity multitudinous,
distributes in the whole city scope, the partial pipe networks
监控�are located the remote area, moreover the geographical
position is dispersible. Selects the ultrashort wave
communication method, the cover scope only has more than 30
kilometers; But selects the GPRS method, theoretically in the
wireless GSM/GPRS network cover scope, all may realize the monitoring.
2nd, the data transmission speed is high. The GPRS network
transmission speed theoretically may reach 171.2kbit/s, practical
application 时数 according to the transmission speed about 40Kbps,
but the present common ultrashort wave number passes on the
broadcasting station to transmit fast 率多 is 2.4kbit/s or is lower.
3rd, the system transmission capacity is big. Monitors the
central station to have with each pipe network 监控�realization
real-time connection. Because the pipe network 监控�
quantity is multitudinous, the system request can satisfy the burst
characteristics data transmission the need, but the GPRS technology
can satisfy the transmission burst characteristics data well the need.
4th, the correspondence expense is low. Because GPRS
selects the method which hires by the month costs, the operation
maintenance cost is low
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