Tutorial: Building a Simple Project This setting is a trigger that takes a Boolean value. A value of 1 — either entered manually as above or evaluated from a tag/expression — forces your project to continue reading tag values from the target device even when there are no changes in value. c) In the Enable Write On Tag Change box, type 1 . This setting is also a trigger. A value of 1 forces your project to write tag values to the target device only when those values change, rather than continuously. This saves system resources and improves performance during rutime. d) In the Station box, type 1 . This indicates the I/O device number to be accessed by this driver.
Typically, the PLC is specified as Device #1. e) In the Header box, type 4X:0 . You must use a driver-specific format. The format for the MODBU driver is: register_type : initial_offset Completed worksheet header 10.In the worksheet body, enter the tags and their associated device addresses — for each tag: a) In the Tag Name field, type the name of the project tag. b) In the Address field, type the value to be added to the header to form the complete device address.
Page 79 Register Type Description 0X Coil Status 1X Input Status 3X Input Register 4X Holding Register ID Slave ID Number Tag Name Address Complete Device Address Level[1] 1 4X:1 (Holding Register 1) Level[2] 2 4X:2 (Holding Register 2)