Auto skip is triggered when the system identifies an item failure, such as a valve has failed to open or an actuator has jammed. It tries to skip to the next item. The reason for auto skip in pressurised irrigation systems is to avoid pump shutdown or a burst pipe. The reason for auto skip in surface irrigation systems is to avoid a channel blowing out.
Enabling Auto-Skip
Auto-skip can be enabled or disabled for a schedule when it is created. This setting cannot be changed after the schedule has started.
The default for this auto-skip value depends on the user who is creating the schedule, and it can be changed from the user's Settings page:
How Auto-Skip works
- When an error is detected, the system tries to send a close command to the current item to ensure we don’t end up with multiple items open at the same time. But this command will not work if the device is offline or in error and it may remain open.
- The next item is opened.
- Subsequent irrigation items receive a program update to open sooner.
- For device groups, the entire group is skipped if any item within it fails.
Scheduling Failures
A schedule may fail for a number of reasons. These reasons can be roughly divided into the following groups:
- Communications - the field unit (or gateway) dropped off the cellular or radio network
- Battery - the field unit (or gateway) has shut down due to low battery level
- Cabling - the device is unreachable due to faulty cabling
- Device - pump, actuator or valve report a failure (i.e actuator jammed or pump stopped on high pressure)
- Congestion - where there are large radio networks deployed, or some communications reliability issues within a radio network, messages between the cloud platform and field unit may be getting delayed.
These failures will usually occur in one of the two critical stages of the schedule execution - opening or closing time.
Auto Skip Effectiveness
Whether auto skip will help to keep a pump running or prevent a channel from blowing out depends on the type of failure that has occurred. In some instances, auto skip may not help, and might even make things worse. These include the following:
- If there is a network congestion, no field unit in that network can be reached, so auto skip would not help unless the congestion improves.
- If a unit is experiencing intermittent comms problems but ends up opening, we might attempt to auto skip to the next unit, which may result in multiple bays open at the same time.
Auto-skip can't be prevented by the system for the above cases as they are difficult to identify during runtime. The best way to avoid these situations is to make sure:
- Gateway units are located at good cellular reception.
- Any 900MHz radio field units have line of sight to the Gateway unit. Crops and other foliage that grow over the antenna height will break radio communications.
- All antennas are undamaged.
- Gateway antennas are installed according to the guidelines.
- The number of radio nodes in the network is limited to avoid congestion.