Maple Systems MAPware-100 - Manual (Page 23)

Note: If you are experiencing problems with communicating with the selected PLC, first
verify that the communication parameters are set to the default by clicking on the
Default button on the mouse.
OIT - PLC Interface Settings Group Box
This group box is used to set all of the addresses for communicating with the PLC. There are
three registers that are required for the OIT to operate: The Message Request Register, the
Function Key Coils, and the Status Coils.
The message request register (MRR) address is set in the text box in the Message group box. This
register is used by the PLC to inform the OIT of messages to display or command codes. This
register is read up to five times per second to receive information from the PLC. The value within
the MRR must change before the OIT will acknowledge that a new message or alarm must be
displayed. Checking the BCD Format check box causes the OIT to interpret the value in the
Message Request Register as a Binary Coded Decimal (BCD) value. If this box is not checked, the
value is interpreted as a Decimal number.
The function key coils are used by the OIT to write information about function key activity to
the PLC. The function key coils are continuously read by the PLC ladder logic program to
determine what action to take when a key is pressed or released. The OIT updates this
register upon key activation. The function key coils address is set in the text box in the
Function Key Coils group box. Checking the Retentive check box causes the OIT to read and
return the values of the Function Key Coils when the OIT powers up. If this box is not
checked, all of the Function Key Coils are reset when the OIT powers up.
The status bit coils are used by the OIT and PLC to communicate status information between
the devices. The use of each status bit is explained in the “Operation” chapter of the OIT
Family Operation Manual. The status bit coils address is set in the text box in the Status Coil
group box.
The Address group box is used to specify the PLC address. Some PLCs require that a PLC address
be used in order to communicate with them.
The Source and Destination group boxed are only used in selected PLC protocols. Refer to
the Protocol Guides for more information.
The PLC password may be set in the Password group box. Several PLCs require the
password to be entered prior to any register or coil transaction.
OIT Options Group Box
Three items exist within the Options box: screen saver settings, supervisor settings, and
passwords.
Screen Saver Editor
Use of the screen saver will extend the life of the vacuum florescent display used in the
MAP340D. Maple Systems recommends the use of the screen saver on these models. To
enable the screen saver, check the Enable box and click on the Define button within the
Screen Saver box. The following window will be displayed:
22 OPERATION
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