Allen-Bradley SLC 500 Manual page 155

Configure I/O
Click the Configure I/O button to display the following dialog box.
Inputs
Enter the number of Input words up to a maximum of 100 words (200 bytes). The Start Address is
normally set to 0. You can change the Start Address to create an offset address. Different devices can
reference the same Profibus address but may require an offset for one of the devices. Changing the
Start Address will change the address ranges shown in the Profibus DP Protocol dialog box. The Start
Address is provided so that the user can align the tag address entered in Quick Designer with the
mapped address in the PLC or host device.
Outputs
Enter the number of Output words up to a maximum of 100 words (200 bytes). The Start Address is
normally set to 0. You can change the Start Address to create an offset address. Different devices can
reference the same Profibus address but may require an offset for one of the devices. Changing the
Start Address will change the address ranges shown in the Profibus DP Protocol dialog box.
Addressing
Some PLCs use Byte addressing while others use Word addressing. Select Addressing on Byte
Boundaries or Word Boundaries, based on your PLC type. The range of valid addresses will be
displayed in the Profibus DP Protocol dialog box, which appears when you close the configuration
dialog box.
Word Storage Format
This option allows selecting the way bytes are arranged into words. Selecting MSB-LSB will arrange
bytes from the MSB (Most Significant Byte) to the LSB (Least Significant Byte). Selecting LSB-MSB
will arrange bytes from the LSB (Least Significant Byte) to the MSB (Most Significant Byte. MSB-
LSB will store the MSB in the current address byte and the LSB will be stored in the next byte. LSB-
MSB is stored in the opposite order.
186 • • • • Profibus
QUICKDESIGNER