GE GFK-0787B Noise Reduction Machine User Manual


 
7
7-37GFK-0787B Chapter 7 Programming Information
Storing a Program to the PLC:
the System IS Configured for Online Changes
For a system configured to allow online changes, the following sequence illustrates how
an online ladder logic program change could be done in a triplex CPU System. System
configuration changes are not intended to be done online. (Online ladder logic changes
are intended for system debug and commissioning).
1. Using the Logicmaster 90-70 Programming Software in the Monitor mode, make a
direct or multidrop connection to PLC “A”.
2. Change the Logicmaster 90-70 programmer mode to the Online mode, and change
the CPU Memory Protect keyswitch to the unprotected position (the Mem Protect
LED will be off). Make the run mode store, single word online change, or block edit
at PLC A. A “Program Changed A” message is logged into the PLC Fault Table at PLC
A. “Program Changed A” is logged into the PLC Fault Table of PLC B and PLC C. If
the change affects the state of any outputs, the discrepant outputs are “voted out” at
the output blocks by the 2 out of 3 voting algorithm. The appropriate output
discrepancy error(s), if any, are logged at all three PLCs..
3. Change the CPU Memory Protect keyswitch to the protected position (the Mem
Protect LED is on).
4. Using the Logicmaster 90–70 Programing Software, make a direct or multidrop
connection to PLC B.
5. Change the CPU Memory Protect keyswitch to the unprotected position. Make the
same program change at PLC B. “Program Changed B” is logged into the PLC Fault
Table of PLC B. If the change affects the state of any outputs, these outputs would
now agree for PLC A and PLC B, and the output state(s) from PLC C are “voted out”
at the output blocks by the voting algorithm. The appropriate output(s) from PLC C
will now be discrepant and the appropriate discrepancy and the appropriate
redundancy error(s) are logged at all three PLCs.
6. Change the CPU Memory Protect keyswitch to the protected position (the Mem
Protect LED is on).
7. Using the Logicmaster 90–70 Programing Software, make a direct or multidrop
connection to PLC C.
8. Change the CPU Memory Protect keyswitch to the unprotected position. Make the
same program change at PLC C. “Program Changed C” is logged into the PLC Fault
Table of PLC C. If the change affects the state of any outputs, these outputs would
now agree for PLC A, PLC B, and PLC C, and the output state(s) should no longer be
discrepant. The “Program Changed C” messages can now be cleared along with any
output discrepancy errors that were logged due to the program change.
9. Change the CPU Memory Protect keyswitch back to the protected position (the
Mem Protect LED is on).
Notes
After many online changes are made, fragmentation of memory may occur. That will
prevent subsequent online changes from being made. To make changes, place the