Sedimentation Event Sensor Design Notes P. McGill 20Feb13 PC-104 Stack * Four serial ports will be required: 1) Console 2) EZ-17 Stepper Driver (RS-485) 3) Wakey 4) Fluorometer * Tried to use TS-SER4 board port C, configured as RS-485, to talk to EZ-17. Found that TS-SER4 doesn't support a turnaround time delay between transmission and reception of serial data. Technologic informed us that they ran out of room on the FPGA and the board only supports hardware handshaking, so it is not usable for our application. This forced us to move the EZ-17 to the RS-485 port on the TS-7200, and move the Wakey RS-232 comms from the TS-7200 to the TS-SER4. * Actual measurements on operating stack show: Parvus Enet board draws 170 mA, rest of stack draws 692 mA, for a total of 862 mA @ 5V, or 4.3 W. This doesn't include the additional 80 mA @ 5 V, or 400 mW, needed to activate each relay on the relay board. * Later tests running the PC-104 stack with the 12 V supply off consumes 143 mA at 26.7V (3.8 W) TS-Relay8 Board * The board has screw-terminal connectors (3-pin on 5 mm pin spacing) which will be difficult to access with the boards installed in the housing. We can switch these with Phoenix 1757569 12-pin headers with mating Phoenix 1765344 3-pin terminal block plugs. * The PCH-105D2H relays coils draw 80 mA at 5 V. An alternate relay, the PE014005 available from Digi-key for $4.82 each, draws only 40 mA but has the same 5 A contact rating. Note that the TS-Relay8 data sheet claims 40 mA per relay with the stock relays. Cameras * The Prosilica GC2450C camera has a resolution of 2448 x 2050 pixels. If we allow for some vignetting, and assume 80% of the image sensor height is used, we will use 0.8 x 2050 = 1640 pixels. If these pixels image a round, 2.5 cm diameter plate, then each pixel images 0.025 / 1640 = 15.2 microns. We can conservatively set the resolution requirement at 20 microns. Actual measurements on images from the completed SES in Feb 2013 show that each pixel is 13.9 microns across (72.0 pixels per millimeter). * The GC2450C lens mount is a C-mount with adjustable back focus. * The GC2450C consumes "less than 3.8 W (12 V)" according to the data sheet. This would be 317 mA at 12 V. Actual measurements show 327 mA at 12.14 V, or 4.0 W. * The SES GC2450C is serial number 02-2171A-07710, delivered with firmware 00.01.42.02, Fluorometer * Rob Glatts fluorometer excites at ~470 nm and senses at 590 nm and 690 nm. 590 nm may be a mix of the accessory pigments such as phycoerythrin, and 690 nm may be chlorophyll a. * 690 nm detector is Hamamatsu H7155-01, 590 detector is H7155. Motor * The stepper motor on the McLane sediment trap is a Crouzet p/n 82920001. It is a 7.5 W, 2 N-m, two-phase, 7.5 deg step, bipolar motor. The coils are 10.7 ohms and are rated for 0.59 A, which is 6.3 VDC. * The gear ratio between the Crouzet stepper motor and the plastic spur gear on output of the McLane motor housing is 300:1. It takes 28,800 half steps to turn the small plastic gear one revolution. The metal gears inside the McLane motor housing have a ratio of 60:15 or 4:1, leaving the stepper motor gearbox with a ratio of 75:1. The ratio of the large carousel gear to the gear on the output of the McLane motor housing gear is 220:30. Half steps per large gear tooth: 960 Half steps per large gear revolution: 211,200 Teeth between funnel and fluorometer: 30.5 Teeth between fluorometer and camera: 36.5 Teeth between camera and funnel: 153 Teeth between Hall switch and funnel: 7 * A suitable driver for the motor is the Allmotion EZ17, which is rated for 12 to 40 V, 1.25 A. * The motor must rotate CCW to advance the sample plate from funnel to fluorometer to camera. * The McLane motor cable appears to be terminated with an Impulse AG206-FS connector. Pin 1 is large, 2 thru 6 are clockwise on the female cable connector. * The correct connections such that positive move commands to the EZ17 result in CCW rotation of the motor output gear are: EZ17 J1 Pin McLane Motor Pin Test Con Wire Color Function 3 1 WHT Motor Phase B 4 2 BLK Motor Phase B 5 3 GRN Motor Phase A 6 4 RED Motor Phase A no connect 5 BLU Index Switch no connect 6 BRN Index Switch Note that J1 is the EZ17 motor output connector, and pin 1 has a square pad. Rotating Plate * Friction between the large rotating gear and the fixed plate above it was too great and causing the stepper motor to stall. We removed the 1/16 inch (0.0625 inch) Ti washers and installed 0.080 inch PEEK washers to increase the clearance. Now the large gear moves easily. Hall-effect Sensor * The sensor was designed at SIO. * The Hall-effect IC is an Allegro A3141 * The mating (cable) connector is an RMG-3-FS with the following pinout: 1 - wht - Ground 2 - blk - Hall Signal 3 - grn - +5 V * Pin 1 is large, 2 and 3 are counter-clockwise on the bulkhead connector. * The A3141 sensor requires 9 mA worst case. The EZ17 motor driver has a 200 ohm resistor (data sheet is wrong) in series with the 5 V supply to the A3141. This means that the A3141 may only see 5 - (0.009 * 200) = 3.2 V. This is below the A3141 minimum supply spec of 4.5 V, so the resistor on the EZ17 must be reduced. It can be no more than 0.5 / 0.009 = 56 ohms. To be safe we should use 22 ohms. The resistor is R27 on the bottom of the EZ17. Wakey Board * This board converts +28 V battery voltage to +5 V and +12 V to run the system. The same board will be used in the Rover. * Wakey must have the following features: 1) Convert battery voltage at up to 34 V to 5 V at 3 A and 12 V at 2 A. 2) Be able to sleep by turning off the power supplies and consuming less than 1 mA at 28 V for a given number of seconds up to 2 days. This requires an 18-bit seconds counter, which might as well be 24 bits. This would allow sleeping for 194 days. Correction: sleeping a long time is dangerous, as a mistakenly large sleep time could end a mission. The max sleep time is instead 1092 min, or 18.2 hours (based on a 16-bit seconds counter at 65,520 sec). The longest anticipated time between samples is 12 hours. 3) Provide an isolated 5 V output to power the Rover stir motors at a 50% duty cycle, even while in sleep mode. 4) Listen to a Device Enable signal from the Acoustic Modem on the Rover. This is an open-collector output that can sink up to 80 mA at 40 V. Wakey only has access to the modem's Device Enable and Ground pins, and we want to keep the modem galvanically isolated from Wakey, so an optocoupler and a 9 V battery could be used. * The board can read the battery input voltage. With a 10:1 divider on the 28 V battery input, full scale is 50 V and each bit represents 50 / 2^10 = 49 mV. * The first Wakey boards for SES have features 1 and 2, but not 3 and 4. Wakey S/N 1, built on a ME Labs proto board with TI power supply modules, consumes 9 mA when awake and 410 uA when asleep. Wakey S/N 2, built on a custom-routed PC board with TI SwitcherPro IC power supplies, consumes 6 mA when awake and 30 uA when asleep. * The SES Wakey board works but doesn't have the acoustic modem wakeup feature added as a requirement in 2014. We may be able to use the Rover Wakey board, which is a PC/104 form factor and has the wakeup feature. Specs on both boards are 5 V @ 3 A and 12 V @ 2 A, so Rover Wakey should be able to be substituted for SES Wakey. ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ SES v2.0 uses the TS-7250V2 microcontroller board to simplify and improve the PC/104 stack. 1) Because of additional ports on the TS-7250V2, we can eliminate the Parvus Enet and TSER-4 boards. 2) The TS-7250V2 has an RTC with a replaceable CR2032 coin cell, unlike the previous TS-5620 RTC which had an internal battery that couldnΥt be replaced. 3) The smaller stack should reduce power consumption. * The measured power consumption with the new stack idling is 80 mA at 24 V, or 1.9 W. This is down from ~3.8 W with the TS-7200, i.e. new system uses about 1/2 the power. * On the wet-node simulator, the system draws about 30 mA at 375 V and 100 mA at 48 V. * Serial Port Assignments: 1) Console (DE-9, COM1?) 2) EZ-17 Stepper Driver (RS-485, XUART2 on COM2 header) 3) Wakey (COM2) 4) Fluorometer (COM3) 5) Modem (TS-SER1) * Humidity Sensor - Using BME280 from Adafruit. Sensor has SPI interface and can be read directly from the TS-7250V2 - Sensor is intended for 8-bit SPI reads and writes, but 7250 will only do 16-bit reads and writes. May have to play some tricks in code to get this to work. - Sensor also reads temperature and pressure in addition to humidity. Might as well read all three since theyΥre there. - Upon power, sensor is in sleep mode and all registers are accessible. To make a reading, 1) write 0x01 to reg 0xF2 to enable humidity sampling 2) write b00100101 = 0x25 to reg 0xF4 to enable temperature and pressure sampling and force a sample 3)