מבוא בקרה פניאומטית : הפניאומטיקה שמוצעת ע " י קרוזט משמשת לבקרה של פונקציות במכונות תהליכים ורובוטיקה המופעלים אויר. קרוזט היא ספקית מובילה של בקרה פניאומטית באירופה ובארה " ב. Specialized circuits of purpose built logic and stepping elements provide timing, sensing and sequencing of all machine processes. Specialized circuits of purpose built logic and stepping elements provide timing, sensing and sequencing of all machine processes.
אינפורמציה כללית בבקרה פניאומטית נעדיף להשתמש ביחידות שמאפשרות זמן רב ככל האפשר בין שירות לשירות ובדרגת אמינות גבוהה. היישומים יכולים להיות במקומות של לחות גבוהה,לכלוך,סביבה מגנטית או נפיצה, ואסור שזה ישפיע על פעולת הבקרה. המבנה המודולרי,סימון הפונקציות הנוח ואיבחון התקלות המובנה מאפשרים אחזקה נוחה ואיתור תקלות מהיר וקל.
GENERAL INFORMATION Pressures: from 30 to 120 PSI (2 TO 8 bar)Pressures: from 30 to 120 PSI (2 TO 8 bar) Temperatures: -20 to +160 FTemperatures: -20 to +160 F Connections: Push-in, 5/32” (4mm) O.D.Connections: Push-in, 5/32” (4mm) O.D. Tubing: Nylon or semi-rigid polymersTubing: Nylon or semi-rigid polymers Flow Rates: psi (Cv =.11)Flow Rates: psi (Cv =.11) Internal passages:.106” minimumInternal passages:.106” minimum Lubrication: None requiredLubrication: None required Filtration: 50 micron (recommended)Filtration: 50 micron (recommended) Duty Cycle: 100 million actuationsDuty Cycle: 100 million actuations
בקרות לוגיות הרכיבים העיקריים במערכות לוגיות הם: OR, AND, YES, NOT- כן, לא, או, ו- OR, AND, YES, NOT- כן, לא, או, ו- כל רכיב כזה הוא שער לוגי שיכול להתחבר לשערים נוספים כדי להרכיב מעגל בקרה על תנועה של מפעילים פניאומטיים. בכל רגע נתון מצב היציאה של רכיב לוגי כזה תלוי רק במצב הכניסות הלוגיות, אם יש כניסה או אין כניסה, ואין תלות במצב הקודם של השער הלוגי או באיזשהו אירוע מקרי.
בקרות לוגיות ( המשך ) רכיבים לוגיים,כאשר הם מחוברים ליחידת הבסיס שלהם יהיו תמיד מסומנים ב-3 כניסות מסומנות: 1.מקבל סיגנל כניסה INPUT מרכיב קודם. 2.חיבור לאספקת אויר דחוס SUPPLY 3.סיגנל יציאה OUTPUT
בקרות לוגיות ( המשך ) יחידות לוגיות יכולות להיות מחוברות בצורות מורכבות בעזרת יחידות הבסיס שלהן: 1.אספקת אויר אחת משותפת כדי להקטין דרישות חיבור (אינסטלציה) 2.יחידות הבסיס ניתנות להתקנה קלה על מסילה 3.חיווי בדיקה עצמית קיים על יחידות הבסיס
אלמנטים לוגיים 1 - INPUT SIGNAL 2 - SUPPLY AIR 3 - OUTPUT “OR” FUNCTION סיגנל היציאה (3) יופיע אם סיגנל כניסה 1 או סיגנל כניסה 2 נמצאים. משתמשים באלמנט לוגי "או" (שנקרא גם “OR” element or Shuttle valve) כאשר לפחות אחד מכמה סיגנלים שונים נדרש without exhausting that signal through the exhaust ports of the other devices. The “OR” is a passive logic element and therefore does not exhaust itself.
אלמנטים לוגיים ( המשך ) 1 - INPUT SIGNAL 2 - SUPPLY AIR 3 - OUTPUT “AND” FUNCTION The output signal (3) will only be present when both signal 1 and 2 are present simultaneously. The “AND” element, for multiplication functions, is used whenever 2 or more signals are required to be present before the desired function can begin, and as the general transition element on the top of the PAC pneumatic sequencer.
אלמנטים לוגיים ( המשך ) 1 - INPUT SIGNAL 2 - SUPPLY AIR 3 - OUTPUT The output signal (3) is present if the signal 1 is present. A “YES” element, or Normally Closed Relay valve, is used as a polarized “AND” element as a signal at port 1 will cause the pressure to go from ports 2 to 3. “YES” FUNCTION
אלמנטים לוגיים ( המשך ) 1 - INPUT SIGNAL 2 - SUPPLY AIR 3 - OUTPUT “NOT” FUNCTION In the absence of signal 1 the output 3 is ‘ON’. When signal 1 is applied 3 will go ‘OFF’. A “NOT” element, or Normally Open Relay valve, is used to invert a signal. When the supply is connected to a 2nd input the function obtained is called’INHIBITION’.
אלמנטים לוגיים ( המשך ) 1 - INPUT SIGNAL 2 - SUPPLY AIR 3 - OUTPUT “MEMORY” Function The appearance of signal 1 causes the displacement of the spool, the output 3 being put under pressure. This state is remembered until the arrival of a signal at port. The “MEMORY” element, or Flip-Flop, transforms a momentary signal into a constant signal by shifting the slide from one position to the other position. It will stay in the second position until another pilot signal shifts the slide back to the first position.
LOGIC FUNCTIONS Latching Function SAMPLE CIRCUIT
LOGIC FUNCTION 1 Press Two-Hand Control: Cyl. #1 extends Cyl. #1 extends 2 Press Two-Hand Control a second time: Cyl. #2 extends Cyl. #2 extends 3 Press Reset Button: Cyl.s #1 and #2 Retract Cyl.s #1 and #2 Retract SAMPLE CIRCUIT Sequential Operation
LOGIC FUNCTION A momentary signal from the manual control valve causes a continuous output at A. A second activation of the manual control causes the output to change to B. Binary Function SAMPLE CIRCUIT
Pneumatics Specialist Course Our solutions in pneumatic logic (GB_autopneu.pdf) Boolean algebra (page 51 to 55) Exercises and hands-on (page 57 to 65)
PROGRAMMABLE AIR CONTROLLERS The programmable air controllers (P.A.C.) are modules of logic components specialized for sequential operation of pneumatic devices. Each P.A.C. module controls one step in a sequence. Position indicating sensors confirm that the operation has been completed and advance to the next P.A.C. module. Programming is accomplished by arranging the necessary sequencing steps in progressive order and supplying sensors to confirm each step.
PROGRAMMABLE AIR CONTROLLERS When initiated, the modules emit a output and wait for confirmation that the action has taken place. Upon receipt of the confirmation they ‘step- on’ to the next module in the succession. Each module performs a similar operation until the entire sequence is completed.
PROGRAMMABLE AIR CONTROLLERS The pneumatic sequencer is used in any pneumatic circuit that requires step-by-step operation and feedback signals after each step to ensure safe operation.
P.A.C. MODULES MODULE 2 START SIGNAL (Momentary Input) OUTPUT AT PORT 3 (CONTINUOUS) OUTPUT AT PORT 3 (CONTINUOUS) SIGNAL FROM SENSOR (Port 1) STEP FORWARD TO MODULE 2 STEP FORWARD TO MODULE 2 INPUT FROM MODULE 1 (Momentary) OUTPUT AT PORT 3 (CONTINUOUS) OUTPUT AT PORT 3 (CONTINUOUS) SIGNAL FROM SENSOR (PORT 1) OUTPUT AT PORT 6 OUTPUT AT PORT 6 INPUT AT PORT 7 RESETS MODULES 2 AND 1 TO 0 RESETS MODULES 2 AND 1 TO 0 SEQUENCE REPEATS IF START SIGNAL AT PORT 4 IS STILL PRESENT MODULE 1
P.A.C. MODULES SAMPLE SEQUENCE
P.A.C. MODULES DIFFERENT MODES OF OPERATION: AUTOMATIC SINGLE CYCLE OR AUTOMATIC A two position switch is used to start the cycle in continuous operation. The cycle will repeat automatically without the intervention of the operator. A push button will start each cycle after selection of “single cycle”. In the automatic position the operation is as the previous example.
P.A.C. MODULES DIFFERENT MODES OF OPERATION: SIMULTANEOUS MOVEMENTS REPETITIVE CYLINDER MOVEMENTS When 2 outputs are required from one module, a tee connection is placed on the output. An extra “And” element is used to ensure both input signals are present before stepping on. When an output is repeated in the cycle then the two outputs are piped to an “OR” element. The input is simply connected with a tee connection to both modules. There is no limit to the number of times an output can be repeated.
P.A.C. MODULES DIFFERENT MODES OF OPERATION: TIMER FUNCTION BLEED SENSOR The time delay will be started by the input a. A delay will occur before stepping on to the next step. When the sequence module is switched on a low pressure bleed is delivered out of port 1. When the bleed is blocked by the cylinder the relay switches and the sequencer steps on. The function of each sequence module can be changed by replacing the “And” element which is screwed to the top of the sequence module, with other logic elements.
P.A.C. MODULES CHANGING THE FUNCTION OF A SEQUENCER: NOT FUNCTION PRESSURE DECAY SENSOR The sequence module will only step-on when input a is not present. The sequence module will only step-on when the pressure level in the cylinder is reduced to zero. The function of each sequence module can be changed by replacing the “And” element which is screwed to the top of the sequence module, with other elements.
P.A.C. MODULES SIGNAL FROM START 1-Cyl A extends 2-Cyl A retracts 3-Cyl B extends 4-Cyl B retracts 5-Cycle stops SAMPLE CIRCUIT TWO CYL. OPERATION START
P.A.C. MODULES SAMPLE CIRCUIT SIGNAL FROM START 1-Cyl A extends 2-Cyl A retracts 3-Cyl B extends 4-Cyl B retracts CYCLE REPEATS E-STOP ACTUATED 1-Cycle stops immediately 2-All cylinders retract 3-System resets to first position E-STOP FUNCTION E-STOP OFF START Off Start E-stop
P.A.C. MODULES SAMPLE CIRCUIT ALTERNATE SENSORS SIGNAL FROM START 1-Cyl A extends 1-Cyl A extends a.-Bleed Sensor a.-Bleed Sensor advances advances to #2 module to #2 module 2-Cyl B extends 2-Cyl B extends a.- Timer delays a.- Timer delays 3-Cyl B retracts 3-Cyl B retracts a.-Electrical signal from a.-Electrical signal from Pressure Sensor to Pressure Sensor to solenoid valve. solenoid valve. 4-Cyl A retracts 4-Cyl A retracts 5-Cycle stops 5-Cycle stops
POSITION DETECTORS Position detectors are pneumatic limit switches. They detect the physical presence of an object and send a pneumatic signal. Most control systems depend on feedback from position detectors/sensors to confirm completion of a previous action before proceeding with further sequencing. A number of specialized contacts (pictured here) may be adapted to the valves to make them better suited for their operations. Position Detector DETECTORS
POSITION DETECTORS (CONTINUED) Gap Sensor Bleed Sensor Relay Another type of position detector requires no physical contact to detect an object. The gap sensors and proximity detectors emit a small bleed of air and detect any interruption of this stream. When coupled with very sensitive sensor relays or amplifiers they too can report on the presence of objects and send a confirming signal to the control system. Position Detectors are required in most applications of programmable air controllers. PROXIMITY SENSOR TYPE: POSITION DETECTORS
TIMER RELAYS Timer relays are used to delay the appearance or disappearance of an output signal in relation to the appearance of the input signal. The operating principal entails the filling of a reservoir via a flow restrictor until the threshold pressure of the relay (NC or NO) is reached. The non-return device enables the capacity to be drained quickly, resetting the time delay. Flow restrictors may be ether fixed (.4 sec) or adjustable (15 and 30 sec available). ‘Delay on’ and ‘delay off’ styles are available. TIMERS:
TIMER RELAYS (CONTINUED) NC (ON DELAY) The positive output (NC) timer is often referred to as the “On- Delay” timer. It delays the appearance of an output signal after receiving the input signal. Once the output signal is on it will stay on until the input signal disappears. The input signal must stay on until the desired time cycle is completed. After ‘time-out’ the capacity must be drained to re-set the time delay.
TIMER RELAYS (CONTINUED) NO (OFF DELAY) The negative output (NO) timer is often referred to as the “off-delay” timer. It delays the disappearance of the output signal in relation to the input signal. Once the output signal is off it will stay off until the capacity is drained and the timer re-set. The input signal must stay on until the desired ‘off-time’ has elapsed.
IMPULSE GENERATOR The impulse generator is often referred to as the “one-shot” timer. It transforms a maintained control signal into a single, fixed or adjustable period pulse. Resetting (draining) must take place before a new pulse can be generated. IMPULSE GENERATOR (ONE-SHOT)
FREQUENCY GENERATOR The frequency generator transforms a maintained signal into pulses at adjustable frequencies. Work time of a pulse period is always 1/3rd of the total period duration, 1/3rd on, 2/3rd off.
BLEED SENSOR RELAY The bleed sensor relay supplies a low pressure bleed to a sensing device (bleed or leak sensor). When the orifice of the bleed sensor is blocked by the object which is being detected, the relay switches ON, an output signal occurs at port 3. This output is the same pressure as the supply to the relay. A normally open version is also available. The bleed sensor relay in normally used with sensing device such as a proximity.
AMPLIFIER RELAY The amplifier relay enables a high pressure output signal to be obtained from a low pressure input signal. It is frequently used in conjunction with pneumatic gap sensors type of proximity sensors and is available in NC and NO versions.
SENSITIVE AMPLIFIER RELAY The sensitive relay is designed to supply bleed air to one of the pneumatic sensors via an in-built pressure regulator, preventing unnecessary air loss at the sensor. It then detects a pressure fluctuation and emits a high pressure output at port 2. The unit is available in NC and NO versions.
ADJUSTABLE PRESSURE SENSOR Adjustable pressure sensors (manostats) switch the output when the input signal reaches a predetermined and pre-adjusted pressure level. NC and NO versions are available.
ADJUSTABLE VACUUM SENSOR The vacuum sequence valves (vacuostat) switch the output when the control signal falls below a predetermined and pre- adjusted pressure level. NC and NO versions are available.
VACUUM GENERATOR The vacuum generator is used to create a suction effect on application of a pressure. By blocking the exhaust port a back-pressure is created which cancels the venturi suction effect resulting in blow-out effect at the vacuum port.
TWO-HAND SAFETY MODULE The two-hand safety module is used to ensure operator safety during a dangerous machine movement, cycle or phase. To obtain an output signal it is necessary to give two simultaneous input signals (1 & 2) with a maximum delay of 0.4s. The output is only maintained if the 2 input signals are present. It cannot reappear until both buttons have been released and re-operated.
SUB BASES Each category, or style, of control components has a specially designed sub base for component mounting, tubing connections and common air supply. Internal passages in the sub bases connect to the proper passages on the control component. Provisions are made to connect sub bases to each other, when required, to form manifolds of components. The manifolds, when properly arranged, form pneumatic circuits capable of control functions. Additionally, the sub bases provide a diagnostic function by indicating the progression of pneumatic signals through a given circuit. “Pop-up” indicators progressively follow the movement of the signal with visual confirmations.
SUB BASES (CONTINUED) FOR LOGIC & RELAYS These sub bases provide mounting for all logic and related relays such as timers and pressure switches. Available in singular or associable styles, they can mount components individually or in multiples. Push-in connectors for 5/32” semi-rigid tubing are provided. When used for multiple mountings the associable style can transform it’s internal passages to connect ports 3 to 2 or ports 2 to 2. A manual “selector” is provided for this purpose. (See illustration on next slide) ‘Pop-up’ diagnostic indicators are provided at ports 1 & 3. Ports are numbered and color coded for convenience.
LOGIC SUB BASES SINGLE SUB BASE OR END SUB BASE WITH FRONT CONNECTION (DIN-rail) # ASSOCIABLE SUB BASE WITH FRONT CONNECTION (DIN-rail) # CONNECTIONS_ TUBE dia._ in._ _(mm) 1 - Green - INPUT 5/32” (4mm) 2 - Yellow - SUPPLY 5/32”(4mm) 3 - Red - OUTPUT5/32”(4mm) This sub-base is used to mount a single logic element or it can be used as the end sub-base in a manifold run of associable bases (in this case the yellow supply connector must be removed and inserted in the first base of the manifold) The associable sub-bases can be joined together to form a manifold system. This system must always be closed at the end of the run by joining a single end sub-base to it. Each associable sub-base incorporates a selector which can be turned to select the required function. POSITION 22 The selector in position 22 connects the input port #2 of the sub-base with the input port #2 of the next base. POSITION 32 The selector in position 32 connects the input port #3 of the sub-base with the input #2 of the next base.
LOGIC SUB BASES (continued) 1. Input port (green - port 1) 2. Output port (red - port 3) 3. Supply port (yellow - port 2) 4. Input port integral to sub base sub base 5. Input indicator (green) 6. Output indicator (red) 7. 1/4 turn screws 8. Marking tag 9. Flow direction arrow 10. Mounting tongue 11. Mounting groove 12. Selector
SUB BASES (CONTINUED) FOR PAC MODULES Sub bases for mounting PAC modules enable multiple units to be arranged in tandem for sequential operations. Separate ‘end base pairs’ allow for connections of common air supply, start signal input and ‘loop’ for continuous operation. Push-in connectors for 5/32” semi-rigid tubing are provided. ‘Pop-up’ diagnostic indicators are located at all critical points to confirm presence of both input and output signals. Ports are numbered and color coded for convenience. Two mounting styles, one for 35mm din. rail, one for panel mounting, are available. SUB BASES (CONTINUED)
P.A.C. SUB BASES (continued) INTERIM SUB-BASE WITH FRONT CONNECTION (DIN rail) # END BASE-1 PAIR ENTRY & EXIT- WITH FRONT CONNECTION # CONNECTIONS_____________TUBE dia._ in._ _(mm) 1 - Green - INPUT 5/32” (4mm) 3 - Red - OUTPUT5/32” (4mm) CONNECTIONS_______________TUBE dia._ in._ _(mm) 4 & 7 - Green - INPUT (Start & Reset) 5/32” (4mm) 2 - Yellow - SUPPLY 1/4”(6.35 mm) 5 & 6 - Red - OUTPUT (In-cycle & Reset) 5/32”(4mm) Interim bases, each mounting a single PAC module, are mounted in tandem to perform successive ‘stepping’ operations. These bases are equipped with attaching tabs and self-sealing ports to form manifolds of interconnected air passages. End base pairs cap the ends of interim bases and provide service connections. Attaching tabs and self-sealing ports are compatible with the interim bases. End bases do not mount PAC modules.
1. Input port (green-port 1) 2. Output port (red-port 3) 3. Input port, start (port 4) 4. Output port, in-cycle (red-port 5) in-cycle (red-port 5) 5. Supply port (yellow-port 2) 6. Output port, end of cycle (red-port 6) end of cycle (red-port 6) 7. Input port, reset (green-port 7) 8. Output indicator (red) 8. Output indicator (red) 9. Input indicator (green) 9. Input indicator (green) 10. Cycle start indicator at port 4 (green) at port 4 (green) 11. In cycle indicator at port 5 (red) port 5 (red) 12. Input indicator at port 7 (green) port 7 (green) 13. End of cycle indicator at port 6 (red) at port 6 (red) 14. Supply indicator at port 2 (yellow) port 2 (yellow) 15. Interconnecting ports 16. Mounting screws 17. Direction of sequence 18. Mounting tongue 19. Mounting groove P.A.C. SUB BASES (CONTINUED)
TROUBLESHOOTING HOW DIAGNOSTICS WORK: Crouzet pneumatic control modules are furnished with a built in diagnostic indicator system. Each of the major control elements, and the sub bases associated with them, display a visual indication of input and output signals as they occur. A component malfunction, pressure loss or circuit error can easily be located by tracing the progression of these indicators. INPUT (Port 1) Indicator on sub base Indicator on sub base Indicator on logic element Indicator on logic element OUTPUT (Port 3) Indicator on logic element Indicator on logic element Indicator on sub base Indicator on sub base
TROUBLESHOOTING (CONTINUED) A schematic drawing can be followed by tracing the progression of ‘pop-up’ indicators. Beginning with the air source or start signal the various machine functions may be checked in their order of operation. Color codes, port numbering and element symbols are also helpful tools for detecting faults. INPUT INDICATOR NO INDICATIOR
TROUBLESHOOTING (CONTINUED) Component failure in a tested design is usually indicated by improper output signal (port 3) when supply (port 2) and input signals (port 1) are present. Most components in a circuit are arranged with signals traveling from outputs (red ports) to inputs (green ports) of the succeeding element.
TROUBLESHOOTING (CONTINUED) When a fault is suspected the element should be identified by its symbol and it’s function determined. With this information the diagnostic indicators are again useful in actual testing. By duplicating the proper combination of input and supply signals the binary output for that particular component will be evident by the ‘pop-up’ indication.
DIRECTIONAL VALVES Directional valves or “power valves”, are used to operate larger sized actuators such as cylinders or rotary devices when higher air volumes are required. 1. Size of the valve is determined by the volume required. 2. They may be pilot operated by solenoid or air signals from control devices.
DIRECTIONAL VALVES (CONTINUED) Directional valves receive signals from a control device and direct power to the actuators. They may also provide an exhaust function while at rest. Function of the valves must be matched to the purpose of the actuator and the job to be performed.
DIRECTIONAL VALVES (CONTINUED) The 5/2 Directional Valve provides power to the actuator and an exhaust function as it alternates between positions. Flow ratings for the directional valve must be chosen to accommodate the size and desired speed of the actuator.
DIRECTIONAL VALVES (CONTINUED) IDENTIFICATION OF PORTS 1= pressure inlet port 2 and 4 = actuator ports 3 and 5 = exhaust ports 14= piloting, control function [connecting pressure port (1) with actuator port (4)] 14= piloting, control function [connecting pressure port (1) with actuator port (4)] 12= piloting, return function [connecting pressure port (1) with actuator port (2)] 12= piloting, return function [connecting pressure port (1) with actuator port (2)]
DIRECTIONAL VALVES (CONTINUED) PILOTED VALVES: Directional Valves receive signals from the control system by way of pilot valves. Single pilot valves (mono-stable) can only propel the directional valve in a single direction and must rely on a spring to return it to it’s original position. A dual pilot (bi-stable) unit shifts the directional valve in both directions. Electrical solenoid pilot valves can be used to shift a directional valve. Solenoids can be combined with pneumatic pilots and spring returns in special applications. Some of the symbols for these combinations are shown here.
CONSTRUCTION MATERIALS Poppet - Desmopan Poppet - Desmopan Rings And Diaphragm - Nitrile Rings And Diaphragm - Nitrile Indicators - Hytrel (Elastomer) Indicators - Hytrel (Elastomer) Component Body - Delrin ( Pom) Component Body - Delrin ( Pom) Fittings - Brass Fittings - Brass Spring And Ball - Stainless Steel Spring And Ball - Stainless Steel Screws - Iron Screws - Iron Base Body - Zytel ( Pa66) Base Body - Zytel ( Pa66)
DESIGN FEATURES Poppet technology - elements andPoppet technology - elements and sensors sensors Push-in style tube fittings Push-in style tube fittings Plug-in style (OR and YES elements) Plug-in style (OR and YES elements) Sub base mounted elements Sub base mounted elements (interchangeable) (interchangeable) Self manifolding with common air Self manifolding with common air supply and exhaust connections supply and exhaust connections DIN rail or panel mountings DIN rail or panel mountings