Retrofitting a 1986 Maho MH400E

First check in and out voltages on the bridge rectifier 6v1 and then the transformer. But be careful, if this drop in the voltage is caused from a shortcut then there is a chance something to blowup. Disconnect one of the dc outputs of the bridge rectifier and put an amperemeter.

Test all the possible combination off rails and exe input to ensure the behavior is the same on all the rails and output of the exe.

RotarySMP wrote: How do I go about measuring the 11µA sine waves comming off the scales? With my multimeter on mA, its lowest scale is 400mA. Do I measure between I1+ to I1- or one pole to ground?

I would try measuring the voltage across a load resistor.

Looks like I wont need to measure the 11µA sine wave at present. The EXE board also has +12V test points.

Since the MAHO wiring diagram only showed 5V supply to the glass scale EXE A/D signal processor, I wrongly figured the 12V wasn't needed. Since the MAHO wiring diagrams are wrong on the wiring colors, I connected up 12V to the test point, and sure enough,


Cool, if anyone else wants to interface Heidenhain LS403 glass scales through a 229 281 01 EXE board, the pin out is:
+12V - Red
+5V - Brown
0V - White
A - Green
B - Blue
Z - [need to confirm this, but I think it is grey.]

I'll take 12V from the ITX PSU and add terminals to wire all three EXE'S into.

Finished wiring the MAHO 28A1 relay board I/O into the 7i84 today.







I put the E-Stop and on buttons in a temporary pendant, with a jog wheel I haven't wired up yet.



Mark

Looks awesome for sure!
Regards,
Tom