Pilot for gas pressure regulator RMG 658 So
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E Electronic Station Management with pilot series RMG 658 General Description 658.00 > edition 01/2001 Serving the Gas Industry - WORLDWIDE size="-1">

E Electronic Station Management with pilot serie RMG 658 > 2 size="-1">

Gas pressure regulators normally operate without auxiliary energy. The power required for adjusting the valves (auxiliary power) is taken from the controlled system or the pressure drop between inlet and outlet. The increasing trend towards the integration of gas pressure regulating stations into a central network management system in order to improve network utilisation and to optimise gas supply etc. requires facilities for linking pneumatic valves and electronic control systems.RMG has developed a special equipment design for this interface. The main functional units of the...

loading pressure line Automatic load limiting stage1st control stage Pamin2nd controlstage Pamax3rd electro-pneumatic control stage Base plate vent lineDischarge -throttle Inlet pressure lineFine filter RMG 90510 000 159 Proportional controlmagnetMeasuring line Discharge line > Inlet pressureControl pressureAuxiliary pressure Outlet pressureAtmospheric pressure 4 >

The inlet pressure is fed via the RMG 905 fine filter and then reaches the amplifying nozzle of the auxiliary pressure stage. At the double diaphragm system, the setpoint value is compared with the actual value.In this pilot stage, the controlled auxiliary pressure is applied the top surface of the diaphragm via internal connection.The setpoint spring and the outlet pressure applied via the measuring line act on the lower side of the doublediaphragm system (for this purpose, the load limiting stage stage has a seal below the spring chamber).The outlet pressure force together with the force...

E Electronic Station Management with pilot series RMG 658 > 2.3 Control stage for maximum outlet pressure p amax The outlet pressure is monitored by comparison of set spring force setpoint value and the outlet pressure on the control diaphragm. As the outlet pressure is normally lower than the set maximum pressure, the amplifying valve is in open position. Within this control stage, the auxiliary pressure is normally transferred directly to the electro- pneumatic control stage.If the outlet pressure rises and reaches the setpoint limit, the amplifying valve closes and controls the transfer...

- The load limiting pressure should be set to the load limiting pressure determined at start-up. > - Switch automation system to manual operation- Preset setpoint y of 0 % - Close downstream isolating valve - Open downsrieam bleed valve to atmosphere - Set the desired pressure setpoint at the p > amin stage- Once the p > amin stage has been set, close the downstream bleed line- Open the downstream valve - After switching the automation system from manual to automatic operation, the system will automatically switch to control operation > - Switch automation system to manual operation -...

- Then turn the setpoint screw of the electro-pneumatic control stage counter clockwise until (within one turn) the outlet pressure begins to rise - Then turn the setpoint screw back again (one turn); the outlet pressure should fall again - Set the setpoint screw between these two positions (usually a 180-degree turn) and secure. The outlet pressure should be kept with this setting between the set pressure values of p > amin and p > amax . To ensure that none of the upstream pilot stages limits the control pressure. - Preset a manipulated variable y of 0 % - Close the pressure bleed line in...

Input signal - current (e.g. 4 - 20 mA)I 20 mA10 mA0 mAOutput signal - voltage 4,5 mAShut-down > Time axis t Energy area Time axis t U24 V 0 V f = 50 Hzf > 10 size="-1">

60 4535 10 > Upper reserve Operating range 25 > Lower reserve Shut-down 2310304050607080010090Y - signal in %regulator manipulated variable 4 - 20 mA Vss. Y = S S = stroke > AP

Example according to process flow diagram (755.56) and diagram (915.35): 12 Control loop Control task Priority 1Actual flow qB (meter protection)highest priority 2Nominal flow q n third-highest priority 3Outlet pressure p amin second-highest priority 4Outlet pressure p amax third-highest priority consumption = constant, gas meter is installed in the downstream pipelineՕ the outlet pressure xp > a is controlled within the limits of electronic p > amin - and p > amax control loop due to the operating conditions (xp > a and xq > n ), the operating flow limiter qB > max is currently not active....

The smooth transition to q > n control occurs as soon as the nominal flow reaches the specified q > n setpoint value (outlet pressure pa at the gas meter has increased). > If the outlet pressure pa increases up to the specified setpoint value wp > amax of the pressure controller p > amax, the outlet pressure will be limited again to the specified setpoint value and take over the control. Supplied and consumed volume are once again equal. > Intermittent operation: If the consumption is lower than nominal flow setpoint, the pressure in the downstream network will increase until the pressure...

qn- control qn- control qn- control qB- qn- control p > amax - qn control Xqn Xqn > consumptioin X > qn = > consumptioin < > consumptioin X > qn = > consumptioin Xqb=WqB delivery X qn = consumptioin Xpa X W > qB W > qn qn consumptioinconsumptioin XqBX > qn W > qn XqBX Xq > n

Isolation amplifier Outlet slide valve Supply unit Measuring transducer Potential-free signal connection to SCS 2001 Volume converter Measuring lineDischarge line * Configure flow signals without delay** Setpoint assignment via standardized signal or RS 484 (Modbus RTU) 2/2 solenoid valve closed at zero curr. base plate breathing line main valve pulse signal gas meter Proportional solenoid electro-pneumatic control stage Pulse modulator inlet pressure line > control stagecontrol stage Measuring transducer >