A photo eye is a versatile object you can use to build logic into your conveyor system. Photo eyes can also be linked to a merge controller to notify it when a released slug has cleared designated points in the system.
A photo eye can be in one of four states while it is interacting with items on a conveyor: blocked, cleared, blocking and clearing. Triggers fire when the photo eye goes into the blocked and cleared states. The following image illustrates the various photo eye states and triggers while interacting with items on a conveyor:
You can assign a photo eye custom behaviors or actions that it can perform when it enters either a blocked or cleared state. You can also define how long a photo eye must be in the "blocking" or "clearing" state before it moves to the "blocked" or "cleared" state. The colors for the "blocking", "blocked", and "clearing" states are defined on the properties of the Conveyor System.
For information on events, see the Event Listening page.
The photo eye has the following events:
On Cover fires when an item covers the photo eye.
It has the following parameters:
Event Parameter | Type | Explanation |
---|---|---|
Covering Item | Object | The item covering the photo eye |
Conveyor | Conveyor | The conveyor the photo eye is on |
On Block fires after an item covers the photo eye and the Block Time elapses before the photo eye is uncovered.
It has the following parameters:
Event Parameter | Type | Explanation |
---|---|---|
Blocking Item | Object | The item blocking the photo eye |
Conveyor | Conveyor | The conveyor the photo eye is on |
On Uncover fires when an item moves out of the photo eye leaving it uncovered.
It has the following parameters:
Event Parameter | Type | Explanation |
---|---|---|
Uncovering Item | Object | The item uncovering the photo eye |
Conveyor | Conveyor | The conveyor the photo eye is on |
On Clear fires after an item moves out of the photo eye and the Clear Time elapses before the photo eye is covered again.
It has the following parameters:
Event Parameter | Type | Explanation |
---|---|---|
Clearing Item | Object | The item covering the photo eye |
Conveyor | Conveyor | The conveyor the photo eye is on |
The photo eye implements state using two different state profiles, namely the default state profile, and a custom "PhotoEye" state profile. The custom profile uses the following states:
The photo eye is completely clear.
The photo eye was covered from a clear state, but its block time has not yet expired.
The photo eye is covered and its block time has expired.
The photo eye was uncovered from a blocked state, but its clear time has not yet expired.
The default state profile uses the following states. The current state can be viewed by clicking on the object and then viewing the Statistics pane in Properties.
The idle state corresponds to the clear plus blocking states in the photo eye's custom state profile.
The blocked state corresponds to the blocked plus clearing states in the photo eye's custom state profile.
The photo eye tracks the following statistics. These can be viewed by clicking on the object and then viewing the Statistics pane in Properties.
The number of items that have covered the photo eye but have not yet cleared it. This is usually either 0 or 1, but if the photo eye has an offset angle, it may be greater than 1.
The total number of items that have covered the photo eye.
The total number of items that have cleared the photo eye.
The Photo Eye uses the following properties panels:
The Photo Eye object uses the following properties:
Property | Type |
---|---|
BlockTime | Unit |
ClearTime | Unit |
DensityThreshold | Number |
MassFlowMode | Options |
OffsetAngle | Number |
PhotoEyeHeight | Unit |
RequireGapToClear | Boolean |
SpeedThreshold | Unit |