How to control the pan roof and judge power-off?


Recently, I was planning to build my own remote automated observatory, want to control all devices with SGP, and I have two questions:
1, I’m going to use relay to control the pan roof, maybe I’ll write an ASCOM driver, SGP how to control roof? For example, when the sequence finished, SGP could close the pan roof automatically.
2, when power failure, UPS will support the power and send signal to the computer through the serial port. SGP how to judge power-off for some time (5 minutes), and then park the mount and close the pan roof?

Thank you ~! :grinning:



For the roof control you’d need to write an ASCOM compliant driver that passes conform that SGP could use.

I’m not completely sure of a good way to handle the power loss situation. Maybe write a watcher that would call SGP via our api and issue an abort. We may need to add some handling for this in our api.



If the roof can close with the mount in any position then I’d consider a direct electrical connection between the power fail signal of the UPS and the roof motor so the roof will close when the power fails without involving the PC. That way the roof will close and the mount will be safe. The data that SGP continues to collect may be bad but that can be sorted later.

Running through software always has the problem that when the computer fails there’s a tendency for everything to stay open with the mount getting wet.

But if a software solution is required then an ASCOM SafetyMonitor driver would be best. There is already safety monitoring in SGP that’s intended for weather but there is no reason why a SafetyMonitor couldn’t monitor the UPS, possibly as well as everything else.

The roof would need an ASCOM dome driver and the UPS an ASCOM SafetyMonitor driver that reports IsSafe as false when the power fails.

I’m assuming that a pan roof is another name for a roll off roof.



Safety monitor would work well here. Not sure why that didn’t enter into my mind. You’d just have to figure out how to create one based off of your ups.



Thank you, Jared and Chris.
First, I’d like to write a Roof ASCOM driver just as Dome control.
Second, I’ll use a Cloud Sensor, and SGPro can only connect one ASCOM ISafetyMonitor driver. So, there are two ways:

  1. Just like Chris said: a direct electrical connection between the power fail signal of the UPS and the roof motor so the roof will close when the power fails without involving the PC.
  2. Writing a new ISafetyMonitor driver, use the exiting Cloud Sensor ISafetyMonitor driver and check the UPS signal, the new driver will give SGPro the right value of IsSafe property: cloudy or power fail, IsSafe will be false.

Hope to get your recommendation. :grinning:



I thought there was a “Safety Monitor Hub” that would aggregate multiple safety monitors together. I could be completely wrong here. Maybe we discussed it as being nice to have? @Chris do you recall if this actually exists or was this just a “wow, this would be cool!” type discussion?



I think we only said that a Safety Monitor hub would be a Good Idea.

We could really do with more public spirited people who are prepared to develop and support this sort of ASCOM support component.



Continuing the discussion from How to control the pan roof and judge power-off?:

I wrote a SafetyHub ASCOM driver, it can be connected to 3 Safety equipment. 2 currently in use: UPS ASCOM driver (I wrote it myself), cloud sensor ASCOM driver (AAG). Now is the Chinese version, if I have time would translate it to the English version. I am willing to share the source code, who knows Chinese can help translate it to the English version, so that everyone can use.
In addition, I would like to ask a question: I am going to build a remote automated Observatory, hoping by SafetyHub IsSafe property to determine whether SGPro should close the roof and park the Mount, the following options in the figure, how can I set? Thank you!


You are probably the best person to answer those questions as only you know how your roof and scope interact with each other. You can find definitions of the slaving options here:

However, assuming it works like a “normal” roll off roof you probably want the following options set:

  • Slave to telescope - on
  • At Home to Open/Close - off
  • Slave on Sequence Start - on or off, personal preference
  • Park Observatory with Mount - depends on how your roof is implemented. Likely off.
  • Mount Unpark Opens Roof - On
    • Open Roof First - On
  • Mount Park Closes Roof - On
    • Park Mount First - On



Thank you for your compliment and detailed answers.:relaxed:
I would like to learn and practice, if I have any questions, consult your later.
Thank you again!