1.52 Antenna-Wind-Protection

The Antenna-Wind-Protection logical device protects an antenna from high wind speeds by either stopping all antenna movement and fastening the brakes or by moving the antenna elevation up to a stow position where the wind load to the antenna's construction is minimized.

The device monitors two wind speeds, each as a momentary and an averaged value. The wind speed measurement values are typically provided by a Dual-Wind-Speed logical device, but other sources are configurable. It takes the maximum value from the two wind speed meters individually for the momentary and the average reading. These max values are compared to configurable limits in order to evaluate an action to perform. The device provides two protection mechanisms, "stop" and "stow", which are working independently from each other.

Antenna Stop procedure

The device compares the momentary and the averaged wind speed to a pair of limit values. If either the momentary or the averaged value exceeds its limit, the antenna gets stopped by execution of the "stop" macro. This macro should contain all antenna settings necessary to lock the antenna safely in its actual position (switch off tracking, fasten brakes).

Antenna Stow procedure

In parallel to the procedure described above, the device compares the momentary and the averaged wind speed to another pair of limit values. If either the momentary or the averaged value exceeds its limit, the "stow" procedure gets triggered. The stow procedure consists of the following steps:

1. The device issues a warning and wait for a configurable time (default is 30 seconds). During this time the procedure can be aborted without manipulating the antenna's state.
2. After the initial delay has elapsed, the device executes the "pre-stow" macro. This macro should contain any antenna settings which are necessary to prepare the antenna to be moved to its stow position.
3. After the execution of the pre-stow macro has finished, the device commands the antenna to move the elevation to its stow position.
4. Now the antenna waits until the elevation reading matches the commanded stow angle within 0.05 degrees.
5. When the stow position is reached, the devices executes the "post-stow" macro. This macro should contain all antenna settings which are required to lock the antenna in the stow position.
6. After the macro execution has finished, the device turns into the STOWED state.

The procedure may be aborted at any time by clicking the "ABORT" button, but this does not stop running macros nor does it stop the elevation to move to the stow position if this already has been commanded. Clicking "ABORT" simply turns the device into the ABORTED state.

Device window pages

The following table shows which device window pages are available with this individual device type. Tool-bar functions not mentioned here are described at the general description of device windows .

• --- Shows and controls the state of the protection procedures.
• --- The faults page.
• --- The device info page.
• --- The maintenance page. The configuration parameters described below are set at this page.

Configuration parameters

At the maintenance page of the device window there are a couple of configuration parameters which must be set to make the software talk to the Antenna-Wind-Protection device.

Setting up the device

The Antenna-Wind-Protection device depends on a number of macros you have to supply in order to make the device work properly. Macros have been chosen for this because each type of antenna controller requires different settings and commands to perform the actions before and after the stow procedure or to stop the antenna safely.

The device suggests names for these macros which contain the name of the Antenna-Wind-Protection device and a suffix describing what the macro shall do. You may use these names or names of your choice. However, all three macros must exist with the names set at the device's configuration parameters or the device will signal a fault.

Manual release procedure

If the device stopped or stowed the antenna due to high wind speed, the operator has to restore the antenna's state and the state of the Antenna-Wind-Protection device to normal operation conditions. The procedure ist almost the same for stop and stow conditions. It also applies when an antenna stow has been aborted and the pre-stow macro already has been executed.

1. Wait until the wind has calmed down to speeds the antenna mount han handle.
2. Point the antenna back to the satellite, activate tracking (if applicable).
3. Finally click "RELEASE" at the Antenna-Wind-Protection device to re-activate the wind protection procedures.

Variables defined by this device driver