Motion Control Engineering Motion 4000, Manual

Page: 186 / 459

User Interface
4-8 Manual # 42-02-2P24
Troubleshooting Example
Examining the computer memory (as in the example above) is a useful step in troubleshooting.
It is possible to find out if the controller is receiving input signals correctly and if it is sending
proper output signals. It is also possible to look up each of the computer output and input sig-
nals shown in the Job Prints.
The following example explains how to use Table 4.3 on page 4-7 and Table 4.4 on page 4-9 to
check a signal in internal memory.
• Problem: the photo eye will not cause the doors to reopen.
1. Look at Table 4.4 on page 4-9 . Find the abbreviation or mnemonic for Photo Eye input.
• The table shows that the mnemonic for Photo Eye input is PHE and provides an
Address (Add) and Position (1 - 8).
• This information shows where to look for the signal in Table 4.3 on page 4-7 and on
the computer display.
Table 4.3 on page 4-7 shows that the address of PHE is 20 and the position is 7.
2. Notice in the table that PHE is indeed in position 7 on row 20.
3. Now that the address and position have been determined, look up the PHE signal on the
computer.
• First, change the address on the display to address 20.
• Then, look at data bit number 7 (from the right),
which is underlined in the graphic:
This digit represents the computer interpretation of the PHE
signal. If the digit is 1, the computer thinks that the PHE sig-
nal is ON. If the digit is 0 (as shown), the computer thinks
that the PHE signal is OFF.
This information can be used to find the source of the problem. The diagnostic display will show
that the PHE input is ON when an obstruction is present which should interrupt the photo eye
beam. If this is the case, checking the voltage present on the PHE terminal will show if the prob-
lem is inside or outside the controller.