PCB Layout adjustments:
As mentioned in closing the last entry I decided to include the 3rd PSU from the outset. By doing this it means I only have to add 2 drives in the future and wire them to go fully 6 axis. In order to do this I had a fair bit of modification to perform on the basic case which should become self-evident as other aspects are discussed.
Image: Cnt12_50v9.9A_PSU_Pins.jpg:
First job of electronics build was to ID the inputs and outputs on the 50VDC 9.9Amp PSU's. They are originally designed for use with a standard molex connector. but the individual blade outputs readily accept spade terminals and is good firm connection. To be on the safe side I double insulated the unused pins with heat-shrink. I'll clean off the untidy marker pen with thinners if everything works OK.
Image: Cnt13_BOBs_Moved.jpg:
Relocated BOB's to a small shelf mounted on the rear panel. Made from a drive bay. The safety charge pump has also been relocated to the underneath of the shelf. Four screws securing mounting pillars are visible on the left of the picture.
Image: Cnt14_77v8A_PSU.jpg:
The reason for the adjustments. In 6 axis config 77v 8Amp PSU will drive 4 motors requiring 2 Amps each. Both 50v PSU's will then power 1 MAE motor each. MAE's need 7 Amps. Controller would need complete rebuild in future if 3rd PSU not included now. Mounted PSU as shown to balance the case. Case is VERY heavy now requiring support rails. Also visible are alterations to layout of other components.
Image: Cnt15_Assembled_S.jpg and Cnt16_Assembled_T.jpg:
Side and Top view of assembled components with all case mods complete. Front panel switches and fuse holders visible on left of picture. Sockets for drive outputs and limit inputs are next to BOB's on rear panel. Just behind toroid of 77v PSU are sockets for mains input and relay outputs. Top view shows 2 relays moved onto side of case. Pic also shows adjustment to motor drives to create clearance for front panel hardware.
Image: Cnt17_Wiring_A.jpg:
Wiring started. PSU's to Motor Drives, via front panel fuses. Front panel switches are wired and any AC distribution which will be inaccessible when rear panel is attached. Using terminal block on 77v PSU to connect AC Neutrals only. Will be no AC Live connection to 77v PSU until 6 axis required.
Image: Cnt18_Wiring_B.jpg:
Close up of AC distruibution from Omron relay. Wires running underneath 77v PSU plate will all be heat-shrinked for protection.
Image: Cnt19_Wiring_C.jpg:
AC distribution wiring completed. Thin black and red wires on top of 50v PSU's are BOB activate switch. Thicker wires are 5V supply to BOB's. Yellow heat shrink is 12v Fans and SChP power. Black heat shrink on right holds ground and switching connection to all relays. Brown wires on left with red tape are connections to AC Live, Neutrals are blue wires on lower left and green is earth from 77v PSU. Brown with green tape in centre of picture is from Omron relay for Estops.
Image: Cnt20_Wiring_D.jpg:
As is becoming evident my design is quite modular. This allowed a lot of work on front and rear panels to be performed away from the main case. Sockets for drive outputs, mains input and Estop are in the foreground. EStop is a modified IEC connector with one of the pins removed with RED heatshrink. All soldered connections have been insulated with heatshrink. Extra clear heatshrink on drive leads is to cover exposed braided shield and protect where they run close to a PSU smoothing capacitor.
Image: Cnt21_Wiring_E.jpg:
View of limit switch and SChP wiring. New charge pump position. Limits, Charge pump and USB power all wired to the BOB at this stage.
Image: Cnt22_Wiring_F.jpg:
Rough plate I bashed up out of unused bit of drive mount. Made with hammer and vice. Required to create some space between PSU transformer and these relay output sockets. Could be prettier but works fine ... also used to mount terminal block to share AC Live and Neutral connections.
Image: Cnt23_Fully_Wired.jpg, Cnt24_Rear_View.jpg and Cnt25_Front_Switches.jpg:
All wiring complete... should be a working controller at this point. Box to the right in top view is rails for case. Rear view shows all sockets. can just make out mod on Estop socket, pin removed and will block up matching hole on plug to make unique connection. USB power for BOB is on right. Front view shows mods to allow fuse and switch mounting.
Image: Cnt26_Test_Kit.jpg:
Components required to test the controller. Have to make two short motor leads, a set of test limit switches, a relay output lead and an example Estop circuit with switch and bulb.
Next job
Once the kit is completed I'll be able to test all controller functions on the bench before going any further. I'm setting up an old laptop to run Mach2 for testing purposes. That way if I've got something wrong and it eats a machine it won't be dual AMD processors that get destroyed.
to be continued........