Maple Systems Silver HMI504T, Installation And Operation Manual

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The “PLC block pack” feature allows you to take advantage of any groups or ‘blocks’ of registers that allow the
OIT to send a smaller number of update commands to the PLC to get the information needed. The OIT will request
data for up to 32 contiguous PLC registers depending upon the PLC block pack setting and the addresses of the PLC
registers monitored on screen. The PLC block pack # represents the maximum number of ‘skips’ between registers
allowed before the OIT considers a PLC register to be part of a different block.
For example, suppose we wish to monitor the following 7 PLC registers on one screen: %R1, %R2, %R4, %R7,
%R12, %R14 and %R100.If PLC block pack is set to 0, the OIT sends seven separate commands to get the data. If
PLC block pack is set to 1, the OIT checks the spacing between requested registers. If the spacing is more than 1,
then a separate command is sent. In this example, the OIT sends four commands- one command to read R1, R2, and
R4; one command to read %R7, one command to read %R12 and %R14, and one command to read %R100.
With most PLC protocol drivers, more time is spent with ‘overhead’ data than getting the actual data that you need.
With the example above, setting the block pack number to 1 probably reduces the time required to update the PLC
data by as much as 40%, ao properly setting the PLC block pack can have a major impact on the update rate of the
OIT.
If the PLC block pack setting were adjusted to 4 or greater, the OIT sends only two commands- one command to
read %R1, %R2, %R4, %R7, and %R12; and another command to get %R100. The update rate is now probably
three times as fast.
You might think that the best setting is 10 so why not have the PLC block pack always on 10? However, in some
situations, a setting of 10 may actually slow down the update rate. For example, if the PLC registers displayed on
the screen are actually %R1, %R10, and %R40 with the PLC block pack is set to 10, the OIT will send two
commands: one to get %R1 and %R10, another to get %R40. If the PLC block pack were set to 0, then the OIT
would have sent three commands. In this case, however, the three commands probably take less time than the two
commands because the OIT has to receive data for ten registers (%R1-%R10) in one command takes more time than
the overhead associated with two commands. Therefore, you should experiment with this setting if you find that the
update rate is longer than you would like.
Now that you know your way around EZware-500 and its various applications, it is time to start creating your own
project. The next seven chapters show you in detail, all of the features that you can use to create a user-friendly
touch screen graphics operator interface terminal. Along the way, we will attempt to provide you with clear
definitions of each feature and, if necessary, some additional examples of how each feature might be used.
Re start the OIT Au to matically af ter a Pro ject is Down loaded
EasyBuilder can automatically start the application that was just downloaded.
4
To enable automatic restarting of the OIT
1. From the
Option
menu, select
Window Property
. The
Window Property
dialog box is
displayed.
2. Check the Jump To Application When Download Done checkbox..
3. Click OK to exit the Window Property dialog box.
Au to matically Save and Com pile the Pro ject
EasyBuilder can automatically save and compile the project when downloading or simulating.
4
To enable automatic save and compile
1. From the Option menu, select Window Property . The Window Property dialog box is
displayed.
2. Check the
Automatic Save And Compile At Download And Simulate
checkbox.
3. Click OK to exit the Window Property dialog box.
Com pact Flash
Compact Flash (CF) cards enable one to download an EZware project from a PC to a compact flash card, and then
put that card into the OIT, and download the project to the OIT. This eliminates the need for a laptop or PC at the
installed OIT’s location, and makes downloading the same project to multiple OITs simple.
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