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hughgilhespie

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Everything posted by hughgilhespie

  1. Hi Peter, There are dozens of similar models from Omron and I am probably wrong about using the 3009 model. I 'think' the one I used has 4 wires because it allowed me to switch between dark operated and light operated. The 3-wire dark on type (EE-SX3009) is perfect for what you want. When you look at the little internal circuit schematic on the data sheet it shows that the output is an 'open-collector' type so it does need a pull-up resistor connected to the +5 volt supply. The VM110 board has a 20k pull-up built in (2 x 10k resistors in series) on each of the digital inputs. This might be a bit high but try the sensor wired directly without an external pull-up first. If it doesn't work try adding a 1k external pull-up between the V and O connections. HTH, Regards, Hugh
  2. Hi Peter, Yep - there is a pic. I forgot that I actually mounted the sensor on a piece of aluminium angle and the aluminium was screwed to the wood block glued to the observatory wall. IMG_2263.JPG FROM THE ALBUM: Pulsar Motor Drives (19 images)
  3. Hi Peter, Have a look at the attached datasheet for the EE_SX3009. The gap between the two 'arms' is 5 mm wide and 10.5 mm deep. In my setup I use a length of brass strip about 3 mm wide and 1.5 mm thick. I mounted the brass on the flange of the dome so it sticks out horizontally and I mounted the sensor on a piece of wood glued to the side of the observatory. The brass strip is held to the flange by a single nut & bolt, not done up too tightly, so that if for any reason the brass bar hits the sensor, it will just bend out of the way. I think there is a photo showing this in my SGL photo album. Regards, Hugh en-ee_sx3009_p1_4009_p1.pdf
  4. Hi Peter, +1 for Alan's comments. I'm sure your UBEC would be fine. Regards, Hugh
  5. Hi Peter, I'm a bit late to the party - again! Can you tell me which optical switch you have ordered? To confirm what Alan said, you really want an 'on when dark' switch and ideally one that will work with a 12 volt supply. The 3009 will work very happily with a 5 volt supply, as far as I remember, it's the one I use. Getting a +5 volt supply from the VM110 is possible and I'm sure the way Alan described will work but don't forget that the VM110 is getting all it's power from the USB connection to the Pi. So the Pi usb supply will be powering the Pi itself, the VM110 board, the encoder and the optical switch. I know it's late in the day but a 12 volt to 5 volt buck converter module with screw terminals only costs a pound or two and it would eliminate any possible power problems. Just a thought! Good luck with tonight's testing. HTH Regards, Hugh
  6. Hi Peter, Thanks for filling in the chart. I have had a look and as far as I can see, Relays 1 and 2 are not operating. Relay 4 is operating as expected. I can't see any obvious reason why they aren't working but assuming your wiring is as per your Version 18 layout, then something is wrong. The next test is to disconnect the wire that goes from DO2 on the VM110 to IN1- and IN2- on the relay board. Disconnect it at the VM110 end and then power up everything. Now touch the free end of the wire to ground (DC- connection on the relay board). Relays 1 and 2 should operate. If they do work then there is either a wiring fault in the connection to the VM110 DO2 terminal or a problem with the VM110 board. Obviously check the wiring very carefully If they don't work you need to check that your voltmeter shows about +12 volts at the IN1+ and IN2+ terminals. If that voltage isn't right, I would suspect a wiring fault in the links between the 5k resistors. If there is about +12 volts on the IN1+ and IN2+ terminals, try a new, direct wire connection from IN1- to the DC- connector. This should cause Relay 1 to operate. Repeat with IN2- to DC- and check if Relay 2 operates. If the relays still don't work with a direct connection to ground on INx1- and +12 volts on INx+ then I think the relay board may be faulty. HTH Regards, Hugh
  7. Hi Peter, I am confident that the 2.79 volts from the encoder is enough to drive the Digital Inputs on the Velleman board, so I don't think you need worry about that and you haven't fried the encoder. I think that the reason you found the VM110 as Device 3 is that you haven't installed the two jumpers (little shorting links) . This won't have any bad effects but you will need to tell the Lesvedome software that the board is at address 3. The text below is from the Lesvedome help file. Velleman K8055 module address Previous Top Next In Dome and Switch Setup windows, select the address of your Velleman board (0 to 3) in accordance with the jumpers SK5 and SK6 SK5 installed and SK6 installed address = 0 SK5 unstalled and SK6 installed address = 1 SK5 installed and SK6 unstalled address = 2 SK5 unstalled and SK6 unstalled address = 3 For your debugging I think the easiest way to do it is by checking only one thing at a time. If it was me, I think my approach would be like this: Remove ALL connections from the VM110 board. (But remember where they all go) Connect the VM110 directly to my computer via a USB cable. Run the Velleman demo software and, using your voltmeter, check the board is working. I would be very surprised if it's not but if it isn't then I think the only option would be a new board - sorry! OK - the board is working fine. Next we need to get the relays working. What will help here is to connect the relay board to the VM110 but do not connect the encoder or the Hall switch. In other word only connect the DO1 and DO2 terminals on the VM110. Nothing else! Now see what happens when you use the demo software to switch outputs 1 and 2 on and off. You can use your voltmeter to measure the voltages at the relay board COM1 and COM2 terminals. From your post on Friday, it sounds as if DO 1/Relay 4 is working as planned but there are problems with DO2/Relays 1 and 2. I suggest that you make a table in Excel that shows the voltages on all the relay output connections for each value of DO1 and DO2 DO1 DO1 DO1 DO1 INACTIVE INACTIVE ACTIVE ACTIVE DO2 DO2 DO2 DO2 INACTIVE ACTIVE INACTIVE ACTIVE COM1 NO1 NC1 COM2 NO2 NC2 COM3 NO3 NC3 COM4 NO4 NC4 With luck, this should be enough to spot any problems with the relay board or the wiring. Post a copy of the table if you are stuck, we can all have a go at deciphering what's going on. When you have got the relays working as they should, I think the next step is to connect the rotary encoder to the VM110 and check that you see the ticks being counted using the demo software. Then the Hall switch, again using the demo software to make sure it operates as you expect. Only at this point would I think about trying everything using the Lesvedome user interface software - not he full blown ASCOM driver, just the user interface and still using a direct USB connection to your computer. OK - so far so good? Now add the Pi to the mix and see if it all still works? It does - congratulations, you have an automatic observatory! HTH Regards, Hugh
  8. Hi Peter, I am afraid that due to family problems I won't be around much today. I will be back again later on this evening and if you are not sorted by then will offer any help I am able to. Regards, Hugh
  9. Peter, I am fairly sure that Lesvedome does need the encoder output to work. You can test the operation of the encoder on the bench using the Velleman board software. Goto https://www.velleman.eu/support/downloads/?code=VM110 and download the 'Complete SDK Pack for K8055 / VM10 (Rev 4.0). Download and unzip. You will find a little program called K8055N_Demo.exe. I suggest you start with a direct USB connection to a Windows PC without using the Pi as a relay. When you run the software and turn the encoder shaft (with the encoder powered of course) you should see the count increase in one of the windows. If you don't see this you will need to investigate further. But - hopefully - you will get a positive confirmation that the encoder is working and sending a signal to the Velleman board. HTH Regards, Hugh
  10. Hi Peter, It sounds as if you are nearly there! The main thing I would recommend at this stage is don't try and connect everything at once. Just connect the Pi and use the Lesvedome User Interface to see if you can get the correct relays to operate. There was a recent change to Lesvedome - I quote Hello Nicolàs You probably use the beta version 6.0.1.20. With this version if the dome moves less than 3deg in 3 sec. The dome is declared as stalled and it disconnect. If you don't want this feature use version 6.0.12 Clear skies, Pierre Pierre de Ponthiere (Belgium) I think this explains why Lesvedome reported 'motor stalled' and disconnected itself. I suggest you try disconnecting the Hall effect switch and seeing if that helps. Let us know how you get on this evening and I'm fairly sure it won't take much to get you going. Regards, Hugh
  11. Good Luck!! The Lesvedome User Interface is a nice, simple way of testing if the hardware works - or not! If you haven't already downloaded this it's automatically downloaded when you download the Lesvedome ASCOM driver. The User Interface is a stand alone program that is used to input the configuration parameters for the dome and azimuth sensor and to test the operation. After the original download you can find the UI program in C:\ProgramFiles (x86)\Common Files\ ASCOM\Dome\ASCOM.LesveDomeNet\ASCOM.LesveDomeNet.exe. I suggest you create a shortcut to the program as it is rather tucked away. HTH Regards, Hugh
  12. Hi Peter, Have a look at this table. https://www.engineeringtoolbox.com/wire-gauges-d_419.html For single core cable, 18 awg would be OK but 16 awg would be a bit safer. If the cost difference isn't too much I would recommend 16 awg wiring. Regards, Hugh
  13. Hi Peter, Another couple of comments about your circuit. First, you are showing a connection between DI3 and DO3. This is not needed for your application. Or - more accurately - it is only needed if you are going to use the Lesvedome ASCOM Switch driver. For the ordinary ASCOM rotation driver, it isn't needed. It won't do any harm and feel free to leave it in but I thought I would clarify a bit. The second comment might be more important. You show a diode in the connection between DO2 (dome motor direction signal) and DI4 (tells the Lesvedome software what the dome motor direction actually is). This connection is definitely needed for the circuit to work but the diode is not required. My setup works perfectly with just a piece of wire connection the two. If you look at the Charles Harrow schematic, which is considered the 'gold standard' for implementing the Lesvedome system, there is just such a direct connection. As we have discussed, the Velleman digital outputs are ACTIVE LOW, so the diode orientation is correct but it introduces a voltage drop of 0.5 - 1.0 volts and this MIGHT be enough to cause problems. Better to leave it out and just use a piece of wire. And think of all the money saved!!! HTH. Regards, Hugh Harrow_Schematic.pdf
  14. Hi Alan, With the extra ground connection from NC1 / NO2, it looks like everything is good. Regards, Hugh
  15. Hi Peter, One problem with your latest layout drawing is that you don't have a connection between the ground of the 12 volt supply and the DC- connection on the relay board. You do show a connection between the Relay board DC- and the GND connection on the Velleman board but these boards are using separate power supplies and there is no common ground rail. Alan's drawing for this is correct - he shows all the modules connecting to the SAME ground point. You do need this connection and it needs to be one with a decent wire size as all the motor current will flow through it. I am struggling a bit with Alan's drawing of the relay switching as I can't see a path for the current through the motor to ground - this may well just be me but as I see it when Relay 4 operates - to turn on the motor - it connects NO4 to the 12 volt rail. This then connects 12 volts to NC2 and NO1. Relays 1 and 2 are the motor direction relays and are both switched by the Velleman DO2 output. As drawn, with the relays in the NC position, NC2 sends 12 volts to one side of the motor. The other side now needs to be connected to ground. However, it is connected to COM1 and NC1 - as Relay 1 is not activated - and also connected to NO2. At this point the path ends - no connection to ground, no motor turning............... Final point - sorry to be so negative. You DO NOT NEED a resistor in the supply line to the Bourns encoder!!!!!!!! I think I know who recommended this and it is just plain wrong. I have attached the manufacturer's data sheet for the EM14 range. All that is needed is a connection to a 5 +/- 0.25 volt supply. I will have a look at the relay circuit in more detail later - as I said I could be wrong on this but at the moment I can't see it working. HTH, Regards, Hugh BournsEncoder.pdf
  16. Peter, I'm sure you know this, but in order for the relay to operate, as well as connecting the IN+ and IN- terminals, you also need to have the relay board connected to the 12 volt supply. The relay won't operate if you are only connecting to the IN terminals. Regards, Hugh
  17. Alan, Good analysis! I think you are spot on and the voltage measurements show that there is a current limiting resistor in series with the photodiode. Hopefully, Peter's tests will confirm that the relay will operate as required with the IN+ terminal connected directly to the positive rail when the IN- terminal is shorted to ground. It's a nice idea of yours to order a relay board yourself. They do seem useful things to have around. Regards, Hugh
  18. Hi Peter, I think one resistor will be fine - perhaps Alan could confirm that? Do you have a multimeter with an ohms range? If you do, you can check to see if there is a suitable resistor already fitted on the relay board. With the board not connected to anything else, measure the resistance between IN1+ and IN1- with the red multimeter lead connected to IN1+. Then swap the meter leads over and measure again. If one reading is a few thousand ohms and the other very high then there is a suitable resistor on the relay board and you don't need an external one. Just connect all the IN+ terminals to your 12 volt supply. If you don't have a multimeter I do recommend you get one - it will be really useful when you build your dome driver. This one from Amazon looks OK and not too expensive. https://www.amazon.co.uk/Pocket-Digital-Multimeter-Ranging-Multimeters/dp/B015Z451ZY/ref=sr_1_9?crid=2TO2WULPN4THF&keywords=multimeter+tester&qid=1558353050&s=gateway&sprefix=multimeter%2Caps%2C188&sr=8-9 HTH, Regards, Hugh
  19. Hi Peter, I've been looking at your 'final' schematic again and I think you MAY need to add pull-up resistors to make it function in the way you need. A bit of background. The digital outputs from the VM110 are 'open collector' outputs. When they are switched ON by the Lesvedome software, the output terminal is connected via a LOW resistance to ground. When they are OFF, they are still connected to ground but this time via a very high resistance. What you need is a way to convert this resistance change into a voltage change to operate your relay board. You get the necessary voltage change by using a 'pull-up' resistor connected beween the digital output terminal and the positive supply. When the resistor is in place, when the DO is OFF, it's potential is pulled up to the same as the positive supply. However, when it turns ON, the voltage at the output terminal drops to very close to zero as there is a low resistance path to ground. The combination of the pull-up resistor, say 5000 ohms and the on-state low resistance, say 1 ohm make up a voltage divider of total resistance 5000 + 1 ohms. In the on state, the output voltage is 0nly 1/5001th of the positive supply voltage. The reason I say you MAY need to add a couple of pull-up resistors is that the relay board MAY already include these resistors. The relay board uses optical isolators so the input circuit is something like this: Please note - this is just my guess and it might be wrong. However, if it is like this then you already have a suitable resistor, the one I have called Rd. To make this circuit work, as well as connecting the IN- terminals to the Velleman digital outputs, you will need to connect the relay board IN+ terminals to your +12 volt supply. Then when the software switches the Velleman output to ON, current can flow through the light emitting diode in the optoisolator on the relay board. This triggers the matching phototransistor and activates the relay coil. Bingo!! There is one other assumption here - that the DC supply to the Velleman board and to your relay board share a common ground. I am sure this is the case so this will work. I am sorry if this is too confusing but I think you will need to experiment - if the relay board comes with a schematic then you can easily see what you need to do. If not you may have to experiment. In the latter case, I strongly suggest that you NEVER connect the positive line 12 volt supply directly to the IN+ relay terminals. Always use a resistor in series with a value of between 1000 and 10000 ohms. (Because if the resistor I called Rd doesn't exist you would immediately burn out the photodiode in the optoisolator) Regards, Hugh
  20. Also, I forgot to say that the free program, WakeOnLan from Aquila Technology works very well https://wol.aquilatech.com/ . You need the MAC address of the remote machine and you have to make sure that WOL is enabled on the remote - loads of U-Tube vids to help here. Regards, Hugh
  21. Steve, When I use Windows RDP I shut down the remote machine by pressing the Alt + F4 keys, then selecting shut-down from the options given. Works a treat! Regards, Hugh
  22. Hi Peter, I have been away from this topic for a few days but it seems as if you are making good progress. One thing that occurs to me is that there seems to be a bit of confusion about the power supply of the VM110 board. The board is actually powered by the 5 volts from the incoming USB connection. The chip on the board that runs everything is a PIC18F family processor that actually runs at 3.3 volts. For reference, I have attached the construction instructions for the K8055n self-assembly board. This is actually identical to the VM110 board. The instructions include a circuit diagram for the board on page 15. This shows the 5 volt supply from the USB socket and the 3.3 volt regulator to supply the PIC chip. So the important thing to realise here is that you need to be sure that the Raspberry Pi that the VM110 is connected to via USB can supply sufficient current to run the VM110 board. I don't have any experience with RPis so I can't help you there. Next is the confusing CLAMP connection on the VM110 board. This does NOT supply any power. It must be connected to the EXTERNAL +12 volts (or whatever voltage you are using) and it's function is to protect the ULN2803a chip against the high voltages that occur when an inductive load, such as a relay coil, is switched on and off. The ULN2803a chip is a buffer/signal level shifter chip and the VM110 board uses two of them. One for the digital inputs, DI 1 to 8 and one for the digital outputs, DO1 to 8. I have attached the Texas Instruments datasheet for the ULN2803 chip and also a sketch showing how you need to connect the digital outputs. Basically, the digital outputs are like electronic switches. One side of the switch is connected to ground and the other side is connected to the appropriate Digital Output terminal. The thing that you are switching on or off (relay coil or whatever) has one side connected to the DO terminal and the other to the EXTERNAL positive voltage supply. This can be any voltage up to 50 VDC. When the switch 'closes' there is a low resistance path for current to flow from the positive supply, through the load and then to ground. So, for your case, the relay coil becomes energised. When the switch is 'open' there is no path to ground so the coil doesn't become energised. Actually there is a very high resistance path and a microamp or two does flow through the load but nothing like enough to energise the relay coil. As I said in an earlier post, the current through the each of the loads being driven by the chip can be up to 500 milliamps - subject to a total of 2.5 amps at any one time . HTH Regards, Hugh k8055n_Schematic.pdf uln2803a.pdf ULN2803a Darlington.pdf
  23. I usually upgrade my Windows 10 computers to Windows 7.
  24. Hi Peter, Many thanks for the detailed explanation of what you are trying to do. I have no experience with Raspberry Pi's and their software so I can't comment on your proposed wifi link but as it is tested and working I am sure it will be fine. So, if I am understanding correctly, you will install the VM110 board and the associated relays in the rotating part of the dome alongside the existing Rigel kit. Then you will have some sort of master switch that will allow you to use either the Rigel system manually or the Lesvedome software remotely to control the dome rotation - and hopefully - the shutter opening and closing at a future stage. More questions I'm afraid. As far as I know, most people who implement the Lesvedome system use the Charles Harrow schematic with 6 dpdt relays. Is there a particular reason you are using an alternative circuit? The Harrow design would give you all the shutter control circuitry for the future. From my own (bitter) experience I can tell you that it is MUCH harder to try and modify things later than to try and include everything you might want from the outset. Next the Bourns encoder. I am sure you know this but the VM110 board can only cope with a relatively low pulse rate from the encoder. The pulse rate of course depends on how many times the encoder turns per dome revolution and the dome rotation speed as well as the inherent ppr rating of the encoder. For my Pulsar set-up I needed an 8 ppr encoder. Anything above that was too fast for the VM110 board. I would strongly suggest you do NOT use a Hall effect sensor for the home position sensor. These sensors have a high level of hysteresis and are not really suited to position measurements An optical switch would be much better. I used an Omron EE-SX3009-P1 switch. This came from RS I believe. This switch has a slot with an IR light emitting diode on one side and a phototransistor on the other. When anything interrupts the light path it triggers the switch. As the slot width is only 5 mm wide you are guaranteed a home position accuracy to better that 5 mm. As Alan explained, these switches, like the Hall effect switches, are active devices and need power connections as well as the switch output. The switch that I used operates at 5 volts as does the Bourns EM encoder. Bear in mind that you will need a suitable 12 volt to 5 volt converter to power these. Again, there are hundreds of suitable small buck-converters with screw terminals on fleabay. How you actually make the stuff depends on your level of experience. My method (a very basic method indeed) is to first decide on what modules are needed and to get their dimensions. Then I do a drawing (I am very old so I use Microsoft Visio) that shows all the modules and where there connections are. Then move the modules around on the drawing until I have some sort of reasonable layout. Then I add the wire runs to the drawing. The idea is that you end up with a layout that can be made by screwing everything to a single sheet of Aluminium. Obviously you need to make sure that the aluminium sheet will fit somewhere in your dome. A quick aside - I had a horror of drilling holes in my Pulsar, so I mounted everything on plywood panels that I glued to the inside of the dome. I use CT-1 construction adhesive, very good stuff! So, I suggest that the next step for you is to finalise the design as best you can. Step 1 : Which circuit will I be using? Step 1 : What modules do I need? Generic at this stage, e.g. a relay module, a power supply module, VM110 board, master switch module....... Step 2 : Decide on the actual components - which relay module? which power supply module? .................. Step 3 : Best thing is to actually buy them but if not get hold of the dimensions somehow. Step 4 : Work out how big your base plate can be and what size it will be then do a drawing of the shape. Step 5 : Add simple drawings of all the modules and where there connections are Step 6 : Fiddle about for hours moving things around until you're happy then add the wires / connections to the drawing. Step 7 : Buy a bit of aluminium sheet - hopefully already cut to size - drill the holes to mount everything, and .... Step 8 : Make it!! I know this is all a horrible over-simplification but it really is doable. Let us know which circuit you want to use and I am sure we can come up with some more definite help. Regards, Hugh
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