As mentioned in an earlier blog entry, one major part of the project is the upgrade of the telescope controller.
As it can be expected, the PC and the software never got an upgrade. Never touch a running system! So currently we have a custom built software running on MS DOS on a vastly outdated PC where getting spare parts is a science of its own. Luckily, we have some well aged connections of our own!
So while parts kept dying we could find replacements in a reasonable time. However it is not feasible to upgrade the current system for Remote Control.
And then we said:
“Cool at least we can keep everything from the Motor Driver onward.”
Sadly the answer was a clear “No!”
You see, not only do we have a custom built software, but also is this software is communicating with custom built ISA cards. Said ISA Card incorporate all the necessary hardware and the DC drivers to move the telescope, just updating the software part would be asking for hardware trouble later on.
Thus finding a controller that fulfills our needs was not so easy. Especially problematic is, that with our telescope size we are in a bad spot (we discussed the telescope itself in the post Tech – The Telescope). To big for the cheap stuff (also we have DC motors and not steppers) but to small to realistically afford the stuff the big telescopes use. And we really wanted to keep the motors and especially the encoders.
What we found was the SiTech Servo Controller II.
We already had a go at it and played around with the controller and one motor of the telescope. Looking at the 50+some page Manual and the 32 page config guide we were a bit scared about the whole process. But in the end we managed to get the controller working and the motor running quite nicely.