+++++++++++++++++++++++++++++++++++++++++++++ + + + D0 TRIGGER RACK POWER SAFETY SYSTEM + + + +++++++++++++++++++++++++++++++++++++++++++++ Michigan State University 11-APRIL-1990 Revised 25-SEPT-1991 GENERAL DESCRIPTION The Rack Power Safety System is to be used for power control and fail-safe operation of the D0 Trigger Instrument Racks and associated cooling system. The RPSS system will service up to 13 Racks and a cooling Fan and provide for two independent power control and keyed lockout panels. The system monitors the Racks and cooling system and in the event of equipment failure or fire will shut down power to the D0 Racks and Fans and indicate the cause of shutdown. Basic Operation The RPSS continually monitors five Fault Sensors in each of up to 13 instrument Racks and displays the current logical condition of each sensor. It also monitors two Control Panels, each consisting of momentary contact switches for Start, Stop, and Emergency Stop controls. Each Control Panel also contains a Keyswitch for lockout capability, such that both Control Panels need to be unlocked for either to operate. The RPSS monitors a single set of three Global Fault Sensors. All sensors need to be indicating correct operation of the Racks and cooling system for power to be maintained to the Racks and Cooling System. Normal Startup and Shutdown sequences are initiated by the Control Panel buttons 'Start' and 'Stop' and provide a delay such that the air circulating Fans are run ten seconds before Rack Power is turned on and remain on until ten seconds after the Racks are turned off. Fault or Emergency Shutdown sequences immediately remove power from both the Racks and air circulating Fans, and are initiated either by the manual Emergency Stop buttons on either Control Panel, or by any of the Fault Sensors attached to the system. The status of the RPSS system is displayed via LED's on the Display Panel, and when the RPSS is powered up will display one of five conditions - Off, Startup, Shutdown, Fault, or Run. When RPSS is in the Off State, power is shutoff to the Racks and Fans, and all Fault Sensors, except those that detect proper Fan operation, should indicate Normal Conditions. The Startup and Shutdown States indicate that the system is running only the Fans for the required 10 second period. The Run State indicates normal operation of the D0 Racks and Fans, while the Fault State indication means that a sensor has detected a problem and that an Emergency Shutdown has occured. Fault State will also be indicated when one or both Keyswitches are locked off on the Control Panels, or following an Emergency Stop executed from a Control Panel. During the Fault State the Fault LED's indicate the conditions of the Fault Sensors at the time that a fault was detected and do not update to reflect any changes detected after the initial fault. There is a manual Reset switch on the Display Panel that will cause the Fault LED's to be updated and a return the RPSS to the Off State if the sensors no longer indicate a problem. The RPSS will not return control to the Control Panels or exit from the Fault State until all Fault Sensors indicate Normal Conditions. Normal Conditions are defined as follows: The Keyswitches on both Control Panels are engaged. Emergency Shutdown is not being pressed on either Control Panel. No Global or Rack Sensor is indicating a fault, EXCEPT Air Flow. Air Flow is being sensed if the Fans have been running for longer than 10 seconds. The RPSS display panel has two LED lamps which display the status of Rack and Fan relays. Rack and Fan power is controlled by two solid state relays that control single phase 120vac to two AC outlets on the RPSS cabinet. All Fault Sensor and Control Panel connections are made through 16 seperate DB15S 15 pin cable connectors. The RPSS requires 120V 50/60 hz AC at approximately 2.5 A. Control Panel Operations Normal operation of the D0 Rack and Fans from either Control Panel requires that both Keyswitches be engaged and that all of the Fault Sensors be indicating Normal Conditions. When the Fans are off, it will be normal for each Rack to display an Air Fault indication. Pressing Start on either Control Panel causes the Fans to be powered on and, after a 10 second delay, the Racks are powered on. During this delay the RPSS displays that it is in the Startup State and the Air Fault indicators should go out as Air Flow is sensed. At the end of the 10 second delay, provided no faults are sensed and Air Flow is sensed in all Racks, Power will be provided to the Racks and the Run State will be indicated. Shutdown is initiated by pressing Stop on either Control Panel. The RPSS indicates Shutdown State and turns off power to the Racks, while maintaining power to the Fans for 10 seconds. At the end of this delay the Fans are shut off and the RPSS returns to the Off State. After the Fans are turned off the Air Flow Sensor Display should light up as the Air Flow Sensors cease to detect air flow. Detectable Fault Conditions The Fault Sensors in each Rack detect four Fault Conditions that require shutdown of power : over Temperature, low Water Pressure, lack of Water Flow, and lack of Air Flow. The Global Sensors detect over Temperature, Smoke, and air Fan Motor Overload. The Control Panel buttons for Emergency Shutdown and the lockout Keyswitches are also treated as Global Fault Sensors as both must be closed for Normal Operation. A Spare sensor input is provided for each Rack and is to be wired shorted for a non-fault indication. All sensors must appear to the RPSS to be simple on/off switches, CLOSED indicating no fault and OPEN signalling a fault condition. (The Fan Overload detector is the single exception; open means Normal Operation, closed means that the Fans are overloaded.) Any of the following conditions constitute a fault and initiate immediate shutdown of power to the system and entry into or continuation of the Fault State : > Smoke detector switch open on the Global Sensors. > Temperature switch open on any Rack or Global Sensor > Water Flow switch open on any Rack > Water Pressure switch open on any Rack > an Emergency Stop button has been pressed momentarily (opened) > the lockout Keyswitch has been opened on either Control Panel > any Air Flow detect switch has opened while Racks are powered on > Fans have been running 10 seconds and one or more Air Flow switches are not closed. > Fan Overload switch is closed. During the Fault State, the condition that initiated the Fault will be indicated by one or more of the Display Panel LED's, the Fault State will be indicated and both Rack and Fan power will be off. The Control Panel will become inoperative and the RPSS will react only to pressing Reset on the Display Panel. Reset Operation Reset must be pressed to exit the Fault State. Pressing Reset will update the Display Panel with current sensor information and if all is well will bring the RPSS into the Off State. The offending sensor signal will be displayed if Reset does not exit the Fault State. The condition causing the fault must be resolved before the system can be brought up again. A possible exception would be an Air Flow problem, which will not be indicated until the Startup State is entered and the 10 second Air Flow delay has ended. RPSS STATE DESCRIPTION Off State When the RPSS is in the Off State, the Rack and Fan power is disabled. Fault conditions are being monitored and all Fault Sensors can be assumed to indicate Normal Conditions, except that Air Flow is not being sensed, the normal condition when the Fans are turned off. The RPSS enters the Off State upon any of three conditions: 1. Upon power up of RPSS and all Fault Sensors except Air Flow indicate Normal Conditions and Keyswitches are enabled on both Control Panels and Stop, Start, and Emergency Shutdown switches on both Control Panels are not pressed. 2. From Shutdown State and all Fault Sensors (including Air Flow ) indicate Normal Conditions and both Control Panels are in the condition stated in (1) above and 10 seconds have elapsed since entering or re-entering the Shutdown State (see Shutdown State description). 3. From Fault State ,the Reset switch has been pressed and all Fault Sensors and Control Panels are in the condition stated in (1) above. The conditions for exit from the off state are : 1. Any Fault Sensor except Air Flow indicates a fault condition, initiating the Fault State. 2. Emergency Stop has been pressed or a Keyswitch has been disengaged on either Control Panel, causing a Fault State. 3. Start is pressed on either Control Panel and exit condition (1) or (2) is NOT met and Stop is inactive on both Control Panels, starts the Startup State sequence. Startup State When the RPSS is in the Startup State, the Fan is on and the Rack power is off. An internal 10 second timer is triggered and all Fault Sensors except Air Flow must indicate Normal Conditions. If at the end of the 10 second delay all air flow sensors indicate normal air flow then the RPSS will enter the run state. The conditions for entry into the Startup State are as follows: 1. From Off State and all Fault Sensors except for Air Flow indicate Normal Conditions and Keyswitches are engaged on both Control Panels and Start is pressed on either Control Panel and both Emergency Stop and Stop are inactive on both Control Panels. 2. From Shutdown State and all conditions in (1) are met (except for state) and the Air Flow Sensors indicate normal air flow. 3. From Startup State and all conditions in (1) above except State. Note that when Startup State is re-entered from itself the only effect is to restart the 10 second timeout. The conditions for exit from Startup State are: 1. Any Fault Sensor indicating a problem (except for Air Flow) sequences the RPSS into the Fault State. 2. The 10 second timeout is completed and any Fault Sensor indicating a problem (including Air Flow) causes sequence to Fault State . 3. Emergency Shutdown or Keyswitch disengage on either Control Panel, sequences to Fault State. 4. None of conditions 1,2,3 are met and Start is inactive on both Control Panels and Stop is active on either Control Panel then sequence to Shutdown State. 5. The 10 second timeout is completed and all Fault Sensors and Air Flow sensors indicate no faults and both Control Panels have the Keyswitches engaged but otherwise are inactive then the RPSS will sequence to the Run State. Run State When the RPSS is in the Run State, both the Fans and Racks are powered on and all Fault Sensors indicate no faults of any kind. The condition for entry into the Run State is as follows: 1. From the Startup State, 10 seconds have elapsed since last entering the Startup State and both Control Panels have the Keyswitches engaged but otherwise have been inactive for 10 seconds and no faults are detected by any sensor, including the Air Flow Sensors. The conditions for exiting the Run State are as follows: 1. Any fault detected by any sensor attached to the RPSS forces the RPSS into the Fault State. 2. Pressing either Emergency Stop Switch or removing the key from a Keyswitch on either Control Panel causes entry to Fault State. 3. Pressing the Stop Switch on either Control Panel when exit conditions (1) and (2) are not met will cause the RPSS to leave the Run State and sequence to the Shutdown State. Fault State When The RPSS is in the Fault State, power is turned off to both the Rack and the Fan motor. The Front panel displays the condition of all sensors at the time the Fault State was entered, and both Control Panels become inoperative. The conditions for entry to the Fault State are as follows: 1. A fault is reported by any Rack Fault Sensor except for the Air Flow Sensors; at any time regardless of state. 2. Any Global Fault is indicated at any time from any state. 3. A Keyswitch is turned off on either Control Panel at any time from any state. 4. Emergency Shutdown is pressed on either Control Panel at any time from any state. 5. During Startup State, 10 seconds have elapsed and any Air Flow Sensor indicates a fault. 6. During Run State and an Air Flow Sensor indicates a fault. 7. During Shutdown State and an Air Flow Sensor indicates a fault. The condition for exit from the Fault State is : 1. Reset is pressed on the Display Panel and all Fault Sensors are indicating Normal Conditions and the Keyswitches are engaged on both Control Panels and Emergency Stop is not being pressed on either Control Panel then sequence to Off State. The Fault State is re-entered if Reset is pressed and the exit condition is not met. Note that pressing Reset will update the Fault LED display and also that the fault causing the shutdown must be corrected before the system will exit the fault state. The Reset Switch is only effective when in the Fault State. Shutdown State During the Shutdown State, the Rack power is off and the Fan power is on. After a delay of ten seconds the RPSS normally sequences to the Off State. All fault detection, including Air Flow, remains in effect during the Shutdown State. Entry Conditions for the Shutdown State : 1. From the Run State, No Faults are reported by any sensor and Emergency Stop and Start are inactive on both Control Panels and the Keyswitches are engaged on both Control Panels and Stop is pressed on either Control Panel. 2. From the Shutdown State, All conditions in (1) except for state will cause re-entry to the Shutdown State, effectively restarting the 10 second timer. Exit Conditions for the Shutdown State: 1. Any Global or Rack Fault being indicated (including Air Flow) causes the RPSS to enter the Fault State. 2. Emergency stop pressed or Keyswitch disengaged on either Control Panel sequences to Fault State. 3. Start is pressed on either Control Panel and conditions (1) and (2) not met causes the Startup State to be entered. 4. The 10 second delay has timed out since the last entry into Shutdown State and conditions (1) and (2) are not met the RPSS goes to the Off State. RPSS State Diagram .--------------> RUN --------------. | | | | | | | ,-------------|--------------->| | / | | | / V V STARTUP----------> FAULT <---------SHUTDOWN ^ ^ | / | | | | / | |<---------------|-|-----------' | | | | | | | V | `--------------- OFF <--------------' SENSOR CABLE WIRING All sensor and Control Panel connections are thru 16 DB15 female connectors on the back panel of the RPSS, labled J1 thru J16 in the schematics. Cable Connections For Global Sensor Cable (J16) pin signal name wire color 1 n.c. 2 n.c. 3 blower overload purple 4 temperature blue 5 smoke detect white 6 n.c. 7 n.c. 8 n.c. 9 n.c. 10 n.c 11 blower overload ground orange 12 temperature ground brown 13 smoke ground black 14 n.c 15 n.c Cable Connections For Control Box Cable (J14,J15) pin signal name wire color 1 emergency stop switch purple 2 n.c. 3 start switch gray 4 n.c. 5 stop switch blue 6 n.c. 7 lockout switch white 8 n.c. 9 emergency stop ground orange 10 n.c 11 start switch ground green 12 n.c. 13 stop switch ground brown 14 n.c 15 lockout switch ground black Cable Connections For Rack Sensor Cable (J1 thru J13) pin signal name wire color 1 air flow sense black 2 temperature sense red 3 n.c. 4 water flow sense blue 5 n.c. 6 water pressure sense green 7 spare sense gray 8 n.c. 9 air flow ground white 10 temperature ground purple 11 n.c. 12 water flow ground brown 13 n.c. 14 water pressure ground yellow 15 spare ground orange Sensor Line Inputs The return signal wire on each sensor input is wired to a common ground which is also connected to the RPSS cabinet. The signal side of each input pair is connected to +5v thru a 1K resistor, and is loaded with two ALS TTL inputs. With normally closed sensors this is a 5 ma loop, and an open sensor switch is detected when the input voltage exceeds about 2V. Input cables are somewhat susceptable to noise and crosstalk, the typical problem being transient spikes initiating a fault condition without any fault displayed. The input cables should each be wound several turns on ferrite toroids at the RPSS end to prevent false fault detection. 10-april-90 note: The Water Flow Sensor has been changed from a simple switch device to an analog flowmeter, requiring the conversion circuit contained in the Sensor Board which is documented seperately. It was found that the switch type flow sensors failed in such a way that water flow would be falsely sensed as present when it has stopped. The analog flowmeter would fail only in a failsafe manner but requires a conversion circuit to appear as a switch like device to the RPSS. This circuit is powered only by the current through the pullup resistor on the RPSS water flow fault input. POWER, SPACE, FUSE REQUIREMENTS All fuses are slow blowing 1 1/4 " 250 V main line fuse 7 amp logic supply fuse 1 amp rack control relay fuse 4 amp fan control relay fuse 4 amp Cabinet Dimensions Height 5.25 " Width 17.375 Depth 13.25 Relay AC Power Specifications The relay contacts are rated at 48-280 VAC @ 47-63 hz, 25 Amps RMS, and switch at the AC zero volts crossing. They are shunted with MOV transient absorbers which limit the maximum voltage allowed across the relay contacts to 130 VAC or 175 VDC . CIRCUIT DESCRIPTION SENSOR SIGNAL GATING All Fault Sensor inputs are grouped into two categories which generate two signals. The signal 'Fault' is the NOR of all Rack sensor inputs (except for Air Flow), all Global Sensor Inputs and also the Emergency Stop and Keyswitch Inputs, for a total of 59 inputs. The gating is implemented using 30 open collector NOR gates with the outputs tied together in a wire-and configuration. All inputs to the NOR gates are then active high, i.e. any sensor input above 2.4 volts forces the Fault signal down to about .4 volts. A 640 ohm pullup resistor is used and also the signal is filtered slightly with a .0022 uf capacitor. (The global signal Fan Motor Overload is inverted, it is the only sensor which is not active low at the cable input. When Fan Motor Overload goes low, Fault will go low.) All Air Fault Sensor inputs are gated similarly to form the signal Air Fault, which is active low i.e. any Air Fault input above 2.4 volts forces the signal Air Fault to about .4 volts. The Air Fault signal is then input directly to the State machine PAL. The Fault signal is input to a SR flip flop and also is gated with the Rack Power enable signal to act as a fail safe enable for the Rack Relay. If for some reason the PAL logic should fail, Any Fault Sensor reporting a fault would still shut off the Rack Power. The SR flip flop 'remembers' any Fault Signal longer than about 2us and provides the signal 'Fault Mem ' to the state machine. Fault Mem is also used as an enable for the Rack Power Relay, bypassing the state machine. The Fault memory flip flop is reset by either the reset or initialize signals. STATE MACHINE SUPPORT CIRCUITS The State machine PAL is run at about 100 Hz ,a clock is generated by a 555 type square wave circuit (U22) and buffered by inverter U21. A power-up initialize pulse is generated by U21 and an RC network. The signal 'Initialize' goes high when power is applied to the system and switches low after approximately .2 seconds; this signal should be low at all other times. This delay must be longer than 1 clock period for the PAL to initialize properly. The State LED Display (green) will be all on during this time. A 10 second pulse, 'Delay' is generated by 1/2 of U22 .It is triggered by the rising edge of the state machine output 'DLTG' and goes high for 10 seconds or until DLTG goes low, whichever occurs first. DLTG is normally held high, when DLTG is low the signal Delay will also be low. The 10 sec. pulse width is determined by C14 and R32 . The front panel Reset button is debounced by U21,C16 and R14. The switch is a normally closed type, pressing it causes signal 'Reset' to go low. STATE MACHINE PAL Description A type 16R6 registered PAL device is used to implement the state logic in the RPSS. The fuse pattern for this programmed part was generated with AMD PALASM II (V2.23 mkt.) from the source listing in file RPSS.PAL. The actual state machine has 8 unique output states and 8 external inputs of which 7 are used. Pin Name Assignments And Functions Pin type signal name active level 1 input clock state register updates upon rising edge. 2 logic input fault memory TTL low indicates a non-air fault 3 logic input air fault TTL low if air fault is sensed 4 logic input stop TTL low if stop button is pressed 5 logic input start TTL low if start button is pressed 6 logic input reset TTL low if reset button is pressed 7 logic input delay TTL high during 10 sec. timeout 8 logic input initialize TTL high during .2 sec. init time 9 logic input not used tied to ground 10 ground ground tied to ground 11 input output enable tied to grnd. outputs enabled 12 logic output rack enable TTL high during Run State 13 state output off TTL low when in Off State 14 state output fault TTL low when in Fault State 15 state output down TTL low when in Shutdown State 16 state output run TTL low when in Run State 17 state output up TTL low when in Startup State 18 state output deltrg TTL low starts 10 sec timer 19 logic output fan enable TTL high enables fan power 20 power vcc tied to vcc Note: in table , capitalized state names refer to RPSS states, not to PAL state machine states. The differences are described in next section. PAL State Machine Diagram .-----------------> RUN ----------------. | | M | | K| V | ,---------------|--------------->DOWNA N | / | | | / P | J | | / V R V UPB -------------> FAULT <----------- DOWNB ^ G ^ | / | D | | |F H / | | | | / | L UPA <----------------|-|-------------' | ^ E| | | | C | V | `----------------- OFF <----------------' ^ A B | Any State--->PRESET ------' PAL State State Outputs Logic Outputs _________________________________________________________________________ RUN UP DOWN DELTRG OFF FAULT BPE RPE PRESET 0 0 0 0 0 0 0 0 OFF 1 1 1 1 0 1 0 0 UPA 1 0 1 0 1 1 1 0 UPB 1 0 1 1 1 1 1 0 RUN 0 1 1 1 1 1 1 1 DOWNA 1 1 0 0 1 1 1 0 DOWNB 1 1 0 1 1 1 1 0 FAULT 1 1 1 1 1 0 0 0 'Any State' X X X X X X X X 0= TTL Low 1= TTL High X= Don't Care or Unknown The PAL states and state transitions are nearly identical to the RPSS states previously described with the following exceptions: 1. The addition of state PRESET , only active during power up of RPSS. Allows for initialization of the PAL into a known state. Whenever the initialize pulse is high, the PAL goes into PRESET state. When the PAL is in PRESET, it can only either stay in the preset state or change to OFF when the initialize pulse ends. 2. The state Startup includes PAL states UPA and UPB. UPA precedes UPB and can only proceed to UPB after one clock cycle. During UPA the signal DLTG is low, thus triggering the 10 second timer. 3. The state Shutdown includes the states DWNA and DWNB . DWNA precedes DWNB and operates the timer identically to state UPA above. The following table summarizes the allowed state transitions of the PAL state machine. More details can be found in the PALASM source file RPSS.PAL, which was used to generate the PAL fuse map. PAL State Logic Input Conditions Transition ______________________________________________________ ------------ Fault Air Stop Start Reset Delay Init Memory Fault (A) Any State to PRESET X X X X X X 1 (B) PRESET to OFF X X X X X X 0 (C) OFF to UPA 1 X 1 0 1 X 0 (D) UPA to UPB 1 X X X X X 0 (E) OFF to FAULT 0 X X X X X 0 0= TTL Low 1= TTL High X= Don't Care or Unknown PAL State Logic Input Conditions Transition ______________________________________________________ ------------ Fault Air Stop Start Reset Delay Init Memory Fault (F) FAULT to OFF 1 X 1 1 0 X 0 (G) UPB to FAULT 0 0 1 1 1 0 0 (H) DWNB 1 X 1 0 1 X 0 to UPA (J) DWNA X X X X X X 0 to DWNB (K) RUN 0 X X X X X 0 to FAULT or X 0 X X X X 0 0= TTL Low 1= TTL High X= Don't Care or Unknown PAL State Logic Input Conditions Transition ______________________________________________________ ------------ Fault Air Stop Start Reset Delay Init Memory Fault (L) DWNB 1 1 1 1 1 0 0 to OFF (M) RUN 1 X 0 1 1 X 0 to DWNA (N) UPB 1 1 1 1 1 0 0 to RUN (P) UPB 1 X 0 1 1 X 0 to DWNA (R) DWNB X 0 X X X X 0 to FAULT 0= TTL Low 1= TTL High X= Don't Care or Unknown CRITICAL PATH DESCRITPION Note: During Fault Detection, the signal path from any Fault Sensor to the Rack power control relay is through 2 SSI TTL gates, implementing a mininum complexity critical path from fault sense to power control. The clocked logic of the RPSS is designed to fail safe in such a way that aside from logic power supply failure or SSI chip failure it will still shut down the Rack power in the event that any sensor except for air flow should detect a fault condition. LED DISPLAY CIRCUITS Each Sensor input, in addition to the fault detect logic, also drives a latched LED display . During Normal operation, the logical condition of each sensor input is displayed on a front panel LED. When the RPSS goes to a Fault State, the latches are switched from a transparent mode to a hold condition, and the logical condition of the sensor inputs at the time that the Fault state was entered will be displayed until the fault state is exited. 74ALS580 Inverting latches are used to both latch and drive the LED's . The signal Hold is connected to all of the display latches and when at low level holds the display at the logic condition present at the falling edge of Hold. The latch outputs drive common anode LEDS thru 470 ohm resistors. A LED is on when the latch outputs are at TTL low. The current RPSS State display is connected to the PAL State bits and driven by a noninverting buffer. Two LED lamps also indicate the status of the solid state relays and are driven from the same buffer. Series resistors are used to isolate the drive circuitry from the relay drive signals so that they will not be affected significantly in case of drive circuit failure. The Global Sensors, Emergency Stop and Lockout signals are displayed through latched drivers and follow the same rules as the fault signal display. The Lockout and Fan Motor Overload signals are run through two extra latches to invert the signal for display purposes. The LED displays are 5 LED common anode bar type units and are wired in groups of 3 displays through a 16 pin ribbon cable and header. TROUBLESHOOTING NOTES Pullup Resistor Problem Description Problem: A single fault sense resulting in several LED displayed on adjacent displays, while properly causing shutdown of system. reason : open or defective 1k resistor SIP. During initial testing, a sip resistor package was incorrectly installed producing confusing display information. The electrical problem was that the common pin of a pullup resistor package was open,and that the sensor lines for two adjacent rack connectors were linked together but not to +5v. From the front panel, this appeared as severe interaction between sensor inputs on the adjacent connectors and display, however the system failed safe in that a fault was always reacted to and shutdown occured with only the display appearing to malfunction. Fault Sensed But Not Displayed Problem: Fault sensed and system shutdown but no indication is displayed. Reason: The sensor inputs are designed to cause shutdown upon any sign of a fault condition. High EM noise (particularly on the longer cables) or sensor switch signals less than 50 ms in duration may trigger a fault detect but not get latched into the display registers. 10-april-90 note: With the addition of the sensor board, the conversion of the analog flowmeter signal to a digital signal causes the water flow sensor input to have very slow rise and fall times that sometimes will cause a fault to be detected but not displayed. This problem was observed on the RPSS backup unit with the prototype sensor board, however the testing was done using flow rates much lower than what is in use at Fermi. The prototype sensor board operated flawlessly during on site testing at Fermi. If this later proves to be a serious problem then either the RPSS flowmeter input circuit must be modified or the converter circuit on the sensor board must be upgraded to a more complex and independently powered system. It was decided to leave the sensor board circuitry as is because of its simplicity and fail-safe operation. solutions: 1. Sensor cables are linked thru several turns on a toroidal ferrite core near the RPSS end of cable. 2. Sensor fault switches are to be clean contacting and not to toggle quickly. 3. Fault sense internal to the RPSS logic is filtered not to respond to fault signals less than roughly .1 ms in duration. 4. If problem proves to be persistent and/or unacceptable, modification of the state machine design to provide for more input settling time may be necessary. Problem: Rack power will not go on, Rack power indicator will not light up but State indicator indicates Run State . Reason : Failsafe mode of logic circuit operating, State machine pal or associated clock is not operating properly. EOC for active flow sensor July-1991 Using the active flow sensor converter circuit (see flow_sensor_modification.txt) requires a Vcc line to be supplied to each rack from the RPSS board. The sensor cables will be 12 conductor instead of 10 conductor, allowing two unused pins of the DB15 connectors to carry Vcc and GND. Conductor 3 of the sensor cables is converted to Vcc and conductor 11 is converted to power return (GND). LIST OF MODIFICATIONS TO RPSS BOARD - Connect a pico-fuse to pin 3 of J1-J9 - Connect the other end of each of these pico-fuses together to Vcc - Connect a pico-fuse to pin 3 of J10-J13 - Connect the other end of each of these pico-fuses together to Vcc - Connect pin 11 of J1 - J13 to GND After ECO Cable Connections for Rack Sensor Cable (J1 thru J13) --------------------------------------------------------------------- PIN COLOR SENSE LINE NAME PIN COLOR GROUND LINE NAME --- ----- ----------------- --- ----- ------------------ 1 black Air Flow sense 9 white Air Flow ground 2 red Temperature sense 10 purple Temperature ground 3 pink Vcc to flow sensor 11 tan power return flow sensor 4 blue Water Flow sense 12 brown Water Flow ground 5 n.c. 13 n.c. 6 green Water Pressure sense 14 yellow Water Pressure ground 7 gray Spare sensor sense 15 orange Spare sensor ground 8 n.c. PARTS LISTS Logic Board Component List Schematic ID# Description Function J1 db15 for wirewrap Rack 1 Sensor connector J2 db15 for wirewrap Rack 2 Sensor connector J3 db15 for wirewrap Rack 3 Sensor connector J4 db15 for wirewrap Rack 4 Sensor connector J5 db15 for wirewrap Rack 5 Sensor connector J6 db15 for wirewrap Rack 6 Sensor connector J7 db15 for wirewrap Rack 7 Sensor connector J8 db15 for wirewrap Rack 8 Sensor connector J9 db15 for wirewrap Rack 9 Sensor connector J10 AUX db15 for wirewrap Rack 10 Sensor connector J11 AUX db15 for wirewrap Rack 11 Sensor connector J12 AUX db15 for wirewrap Rack 12 Sensor connector J13 AUX db15 for wirewrap Rack 13 Sensor connector J14 AUX db15 for wirewrap Control Panel connector J15 AUX db15 for wirewrap Control Panel connector J16 AUX db15 for wirewrap Global connector J17 16 pin DIP socket Rack 1,2,3 panel LED connector J18 16 pin DIP socket Rack 4,5,6 panel LED connector J19 16 pin DIP socket Rack 7,8,9 panel LED connector J20 16 pin DIP socket Rack 10,11,12 panel LED connector J21 16 pin DIP socket Aux. board connector J22 16 pin DIP socket Rack 13,Global LED connector J23 16 pin DIP socket State LED,reset,lamp,connector J24 34 pin .1" male skt. Power supply and SSR control J25 16 pin DIP socket Aux. board connector J26 16 pin DIP socket Aux. board connector J27 AUX 16 pin DIP socket Aux. board connector J28 AUX 16 pin DIP socket Aux. board connector J29 AUX 16 pin DIP socket Aux. board connector U1 74ALS33 quad 2-in NOR o.c. U2 74ALS33 quad 2-in NOR o.c. U3 74ALS580 octal transparent latch,inverting U4 74ALS580 octal transparent latch,inverting U5 74ALS33 quad 2-in NOR o.c. U6 74ALS33 quad 2-in NOR o.c. U7 74ALS580 octal transparent latch,inverting U8 74ALS580 octal transparent latch,inverting U9 74ALS33 quad 2-in NOR o.c. U10 74ALS33 quad 2-in NOR o.c. U11 74ALS580 octal transparent latch,inverting U12 74ALS580 octal transparent latch,inverting U13 74ALS33 quad 2-in NOR o.c. U14 74ALS33 quad 2-in NOR o.c. U15 74ALS580 octal transparent latch,inverting U16 74ALS580 octal transparent latch,inverting U17 74ALS02 quad 2-in NOR U18 74ALS33 quad 2-in NOR o.c. U19 74ALS33 quad 2-in NOR o.c. U20 74ALS580 octal transparent latch,inverting U21 74ALS04 hex inverter U22 556 dual timer U23 16R6 registered PAL programmed w/GM7A code U24 74ALS541 octal buffer U25 74ALS10 triple 3 in NAND RP1 thru RP8 1k ohm resistor 10 pin SIP ,9 resistors to common node RP9 thru RP20 470 ohm resistor 8 unbussed in 16 pin DIP C10 .1u 50v bypass capacitor C11 .1u 50v timing quality capacitor (using bypass ) C12 33u 15v bypass capacitor C13 .1u 50v bypass capacitor C14 100u 35v timing capacitor C15 33u 35v timing capacitor C16 .1u 50v bypass capacitor C17 .002u 50v capacitor C18 .002u 50v capacitor R8 620 ohm 1/4 watt resistor R9 620 ohm 1/4 watt resistor R10 20k ohm 1/4 watt resistor R11 20k ohm 1/4 watt resistor R12 82k ohm 1/4 watt resistor R13 10k ohm 1/4 watt resistor R14 10k ohm 1/4 watt resistor R15 560 ohm 1/4 watt resistor R16 560 ohm 1/4 watt resistor D1,D2 1N914 diodes end of parts list for aux and main boards only those parts mounted to boards on list no cables here. Power Supply Elpac solv-15-5 Line Filter Corcom type 10VK7 Solid State Relays Crydom type D2425 Varistors G.E. type 130L20B Power receptacle Hubble 15A grounded Panel LED displays NTE3111 (red) NTE3112 (green) EXTERNAL SENSOR DATA Water Flow Sensor : Whitman # P865-1-CR2L 10-april-90 to be upgraded to Proteus #550B analog flow meter Water Pressure Sensor : Whitman # J205G-10S-C1RL Air Flow Sensor : Honeywell # S688 Sail Switch Smoke Sensor : Honeywell # TC804B-1D11 Photo detector Air Duct Smoke Detector Temperature Sensor : Control Products, Inc. # AD023 set at 95' F Note : The Spare Sensor Inputs do not presently refer to an actual sensor .These inputs must be wire shorted .