cantcliff Posted February 27, 2015 Report Share Posted February 27, 2015 Current big project in progress: Sequencing system to control 2 pressure sources through 5 valves, 2 fixtures through a 10 valve manifold, and control the release of failed parts without operator input for differential flow functionality and leak test on customer parts. Current system: 1) V570, No snap module installed 2) 1 - EX-A2X 3) 1 - IO-AI8, currently using 4 pressure sensors a) 2 sensors in fast mode (12 bit), 0-150 psig, 0-10V 2 sensors in normal mode (14 bit), 0-150 psig, 0-10V 4) 1 - IO-DI16 5) 2 - IO-TO16 6) 1.3 amp Omron power supply for V570 and EX-A2X 7) 5.0 amp Omron power supply for Digital Outputs 8) All modules protected by appropriate fuse blocks 9) Custom built enclosure with all IO-points through Dual Row din mount terminal blocks, color coded by IO type. Current rough outline of the program: 1) Buffered I/O on all digital and analog input 2) Two drums, with conditionals to control advancement through the drum, and prevent running certain tests when one fixture is occupied. 3) Start sequence with a full reset of all bits to prevent unintended flow Current Program performance: 1) <1ms scan time. 2) Continuous Checks 1) Low pressure tank monitor a) Monitors tank for pressurization above 1 psi above target Fast cycles vent solenoid to drop pressure Sequences Detail Program information: 1) Activation Test a) Pressurizes the part to low tank pressure Maintains flow path to low tank c) Opens high pressure path .5 seconds d) Closes Low pressure path to pressurize part for leak test e) Checks for activation indicator f) Isolates part from high source 2) Leak Test a) Time based test, calibrated against a standard At the start records the part pressure value from the sensor c) After test sequence time <n> records the final value d) Calculates pressure drop per minute and compares to known calibrated leak standard and rejects or accepts based on standard 3) Reset sequence a) Vents part to low tank Extends reset cylinder c) Repeats activation test sequence to allow indicator to push back in d) Isolates part from all pressure sources e) Opens test fixture if part passes f) Maintains closed fixture if part fails until operator inputs Operator Display: 1) Tank pressures a) Gauge style Green/Red band for quick reference Digital readout of sensor reading for diagnostic purposes 2) Test Sequence running a) In Progress, by Fixture Leak Test c) Activation Test 3) Drum Step (Primarily for diagnostic purposes) In Progress: 1) Calibration sequence for the leak testing 2) Verification sequences for valves 3) Additional digital sensors for part presence and safety Future State: 1) Electronic regulator control of the pressure sources, currently manual regulators 2) Additional tanks and valves to allow both fixtures to run simultaneously 3) Improved Pressure transducers, current versions, while analog are limited to about 11bit of accuracy. 1 Quote Link to comment Share on other sites More sharing options...
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