Руководство - руководство по программированию в среде U90 Ladder (англ.язык)
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Note that different PCs can access a network at the same time, using different M90 units as bridges. However, 2
different PCs cannot simultaneously access the same M90 unit.
To communicate with different M90 units via the bridge, you:
1. Select Network as shown below.
2. Select the M90 you wish to communicate with by entering its unique ID number.
According to the figure above, the PC would communicate with M90 number 2.
However, note that once your project is defined as a Network project, U90 Ladder cannot automatically detect
the bridges' communication settings. In order to communicate via the bridge, your current communication
settings must be identical with those of the bridge. Note too, that the bridge's RS232 baud rate cannot be set
below 9600.
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Ladder Logic
You use Ladder Logic to write your project application. U90 Ladder is based on Boolean principals and follows
IEC 1131-3 conventions.
Ladder Diagrams are composed of different types of contact, coil and function block elements. In U90 Ladder,
these elements are placed on nets.
In any Ladder Diagram, the contacts represent input conditions. They lead power from the left rail to the right
rail. Coils represent output instructions. In order for output coils to be activated, the logical state of the contacts
must allow the power to flow through the net to the coil.
Ladder Net
A U90 Ladder net is the smallest division of a ladder diagram in Unitronics' U90 Ladder software.
Your first ladder element on the left must be connected to the left side of the ladder in each net. You do not need
to connect the last element on the right to the right side of the ladder in each net.
You should place only one ladder rung on a Ladder net.
Power flows through the ladder elements in a net from left to right. If you build a net that would result in reverse
power flow (right to left) the following error message occurs:
Placing more than one rung in a net may cause compiler problems in your project.
Examples:
This net is constructed properly.
This net is constructed properly.
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This net is improperly constructed and contains two rungs.
The rungs in the net below should be placed in two nets as shown below.:
Viewing Logic Power Flow in a net
The Show Power Flow feature enables you to check the logic of a net you create.
You can see the Power Flow directions and, from these, how the net will work in the project.
1. Right-click on the left Ladder bar. The Compiler Results menu appears.
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2. Select Show Power Flow.
3. The net lines change color according to the power flow direction.
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Each color represents a different direction of power flow.
Line Color Power Direction
Dark Green Down
Light Green Up
Dark Blue Left to Right
Light Blue Right to Left
Red Up or Down
Ladder Nets with Feedbacks
According to IEC 1131 - 3, it is possible to create Ladder Diagram nets that contain feedback loops, i.e. where
an element is used as both contact(s) and coil(s) in the same net.
In Ladder Diagram, all external input values such as those associated with contacts are gathered before each net
is evaluated.
In the above example:
Where the net uses the state of its own output, the value of FAN (MB 7) coil associated with an inverted contact
of MB 7 is always the value resulting from the previous evaluation.
However, if the value of FAN (MB 7) is used in any following nets, the latest evaluated state is used.
Deleting Nets
To delete a single net
1. Click in the net number space to select the net. (The white space to the left of the net.)
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2. Select delete
. A dialog box will prompt you to confirm the delete action.
3. The net will be deleted.
To delete more than one net
1. Select the first net by clicking on the left net bar.
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2. Hold the Shift button and click on the last net in the range that you want to copy.
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3. Click Delete on the Standard toolbar.
Placing Contacts & Coils
To place a Contact / Coil on a net:
1. Click once to select the desired contact / coil.
2. Move the element to the desired net position.
3. Click to place the element. The Operand and Address dialog box opens.
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4. Select the Operand type from the drop - down menu.
5. Either type the Operand Address and symbol, open Controller View, or click Get Next Unused Operand.
Click OK.
6. The element appears on the net with the selected Operand Address and symbol
Placing a Function Block
To place a Compare / Math / Logic function block on a net:
1. Click on the menu containing the desired type of function block,
OR
Right-click on a net to display the toolbar, then click on the desired menu;
the menu opens.