Hi,
I am having trouble setting up my mount for auto guiding.
I have a Losmandy GM-100 mount and the original electronic drive system. I have not upgraded to the current Losmandy digital drive board like you see on a G-11, I have the old stuff with a simple hand controller with its 4 push button switches for RA and DEC. The hand controller connects to the drive electronics box with an RJ-12 cable. The RJ-12 port on the drive electronics box is marked HC \ CCD.
I purchased the GPUSB, RJ-12 cable, splitter, and extender cable from Shoestring Astronomy. I connect my GPUSB to my Windows XP SP2 laptop, the GPUSB connects to the SA cable that plugs right into the GM-100 drive electronics box. When I turn everything on the RA motors runs like it should for sidereal tracking and the DEC motor runs as if am pressing the guiding adjustment button on the hand controller. If I launch the Shoestring Astronomy GPUSB test utility, it finds the GPUSB, I can turn the LEDs on and off, but when it try and test the RA and DEC controls they do not work and the mount keeps running in DEC.
I did some research on the SA web site and they suggest testing the voltages on the GPUSB with everything connected. I did this and had some interesting results. Pin 2 is supposed to be ground with pins 3, 4, 5, and 6, for signals. When I use pin 2 as a ground I did not get a low voltage signal on pin 5, it read zero VDC. When I measured signals assuming that 5 MIGHT be the ground, I was able to see the proper high and low signals on lines 2, 3, 4, and 6.
According to the SA site, only 5 of the 6 RJ-12 pins are used. It looks to me as if pin 1, which is normally unused, is used to light an LED on my hand controller.
I think my drive’s electronic controller is not wired to the ST4 standard. This is not surprising, because the mount is quite old, from the early 90s I believe. If this is correct, then I think I need a custom cable to connect the GSUB to the mount. I have the all the gear to make a custom cable, but I am not sure how to proceed.
The other possibility is that the GPUSB is faulty, or if I am really unlucky, the GPUSB is bad and my wiring is not standard.
Has anyone connected an ST-4 autoguider to the old GM-100 drive system? If so, can you provide some help?
If you do not have experience with this specific system, can you provide me with some direction on how to figure out how to wire a custom cable?
Thanks in advance,
Paul
I am having trouble setting up my mount for auto guiding.
I have a Losmandy GM-100 mount and the original electronic drive system. I have not upgraded to the current Losmandy digital drive board like you see on a G-11, I have the old stuff with a simple hand controller with its 4 push button switches for RA and DEC. The hand controller connects to the drive electronics box with an RJ-12 cable. The RJ-12 port on the drive electronics box is marked HC \ CCD.
I purchased the GPUSB, RJ-12 cable, splitter, and extender cable from Shoestring Astronomy. I connect my GPUSB to my Windows XP SP2 laptop, the GPUSB connects to the SA cable that plugs right into the GM-100 drive electronics box. When I turn everything on the RA motors runs like it should for sidereal tracking and the DEC motor runs as if am pressing the guiding adjustment button on the hand controller. If I launch the Shoestring Astronomy GPUSB test utility, it finds the GPUSB, I can turn the LEDs on and off, but when it try and test the RA and DEC controls they do not work and the mount keeps running in DEC.
I did some research on the SA web site and they suggest testing the voltages on the GPUSB with everything connected. I did this and had some interesting results. Pin 2 is supposed to be ground with pins 3, 4, 5, and 6, for signals. When I use pin 2 as a ground I did not get a low voltage signal on pin 5, it read zero VDC. When I measured signals assuming that 5 MIGHT be the ground, I was able to see the proper high and low signals on lines 2, 3, 4, and 6.
According to the SA site, only 5 of the 6 RJ-12 pins are used. It looks to me as if pin 1, which is normally unused, is used to light an LED on my hand controller.
I think my drive’s electronic controller is not wired to the ST4 standard. This is not surprising, because the mount is quite old, from the early 90s I believe. If this is correct, then I think I need a custom cable to connect the GSUB to the mount. I have the all the gear to make a custom cable, but I am not sure how to proceed.
The other possibility is that the GPUSB is faulty, or if I am really unlucky, the GPUSB is bad and my wiring is not standard.
Has anyone connected an ST-4 autoguider to the old GM-100 drive system? If so, can you provide some help?
If you do not have experience with this specific system, can you provide me with some direction on how to figure out how to wire a custom cable?
Thanks in advance,
Paul
