ersanjit
Member
Hello All,
We have been struggling for the last couple weeks with a recurring Remote I/O communication problem. The problem is described below.
This is the network environment:
• PLC 5/40 channel 2A as the RIO scanner.
• Four 1771-ASB modules for 1771 racks.
• About fifteen 1794-ASB modules for Flex I/O racks (three recently converted from Block I/O).
• One 1336-GM1 module for a 1336 drive.
• Two Block I/O modules.
Here is an overview of events (some details are approximate):
• June 3 (in the middle of an extended shutdown): Two Block I/O modules are replaced by two Flex I/O racks. No apparent problems.
• June 4-5: Two additional Block I/O modules are replaced with a single Flex I/O rack. We had difficulty configuring the new rack in a way that would make it work (did not succeed yet).
• June 6: Communication is lost to all of channel 2A (red flashing light on the scanner). No adapter lights are on. Someone had previously noticed one of the 1771-ASB adapters had been faulted, but had been corrected by cycling power. Replaced that module, and the network returned to normal.
• June 7: Successfully configured the new Flex I/O rack. No apparent problems.
• June 19: Start-up from the extended shutdown. Communication is lost with channel 2A. Replaced the PLC5 processor, but problem was not resolved. Swapped the processor back out. Start pulling off RIO cables from adapters one at a time. When the cable is pulled from one of the 1771-ASB adapters, communication with other adapters is restored, and the channel light starts flashing green. Plugged the cable back in, and the fault immediately appeared. Replaced the adapter (a different one than before).
• June 20: Same channel 2A problem. Started pulling RIO cables. The fault disappears when we remove the cable from another of the 1771-ASB adapters, and returns when we plug it in. Replaced the adapter.
• June 23, ~8:00 PM: Same channel 2A problem. Cycled power to the processor and all remote racks, and problem appeared resolved. Replaced one of the Block I/O modules on the basis of a conjecture that it might be a problem.
• June 24, ~1:30 AM: Lost control of the 1336 drive (on channel 2A). The 1336 drive HIM was showing “Connecting …”, with fault lights on. Eventually the fault cleared and could be reset with the reset button for no obvious reason.
• June 24, ~4:30 AM: Same channel 2A problem. Started pulling RIO cables. The fault disappears when we remove the cable from another of the 1771-ASB adapters (the last remaining original one), and returns when we plug it in. Having run out of spare adapters, cycled power to the remote 1771 rack.
• June 28: One of the earlier replaced 1771 ASB adapter was replaced again after the whole channel went down again.
We are unsure why these modules are going bad or what is going bad in them as we don't have a way to test them. The only eye catching thing I could see is that some of the adapters are having some high numbers of reties on channel. Not sure if this is something that I should be concerned about.
Please advice.
We have been struggling for the last couple weeks with a recurring Remote I/O communication problem. The problem is described below.
This is the network environment:
• PLC 5/40 channel 2A as the RIO scanner.
• Four 1771-ASB modules for 1771 racks.
• About fifteen 1794-ASB modules for Flex I/O racks (three recently converted from Block I/O).
• One 1336-GM1 module for a 1336 drive.
• Two Block I/O modules.
Here is an overview of events (some details are approximate):
• June 3 (in the middle of an extended shutdown): Two Block I/O modules are replaced by two Flex I/O racks. No apparent problems.
• June 4-5: Two additional Block I/O modules are replaced with a single Flex I/O rack. We had difficulty configuring the new rack in a way that would make it work (did not succeed yet).
• June 6: Communication is lost to all of channel 2A (red flashing light on the scanner). No adapter lights are on. Someone had previously noticed one of the 1771-ASB adapters had been faulted, but had been corrected by cycling power. Replaced that module, and the network returned to normal.
• June 7: Successfully configured the new Flex I/O rack. No apparent problems.
• June 19: Start-up from the extended shutdown. Communication is lost with channel 2A. Replaced the PLC5 processor, but problem was not resolved. Swapped the processor back out. Start pulling off RIO cables from adapters one at a time. When the cable is pulled from one of the 1771-ASB adapters, communication with other adapters is restored, and the channel light starts flashing green. Plugged the cable back in, and the fault immediately appeared. Replaced the adapter (a different one than before).
• June 20: Same channel 2A problem. Started pulling RIO cables. The fault disappears when we remove the cable from another of the 1771-ASB adapters, and returns when we plug it in. Replaced the adapter.
• June 23, ~8:00 PM: Same channel 2A problem. Cycled power to the processor and all remote racks, and problem appeared resolved. Replaced one of the Block I/O modules on the basis of a conjecture that it might be a problem.
• June 24, ~1:30 AM: Lost control of the 1336 drive (on channel 2A). The 1336 drive HIM was showing “Connecting …”, with fault lights on. Eventually the fault cleared and could be reset with the reset button for no obvious reason.
• June 24, ~4:30 AM: Same channel 2A problem. Started pulling RIO cables. The fault disappears when we remove the cable from another of the 1771-ASB adapters (the last remaining original one), and returns when we plug it in. Having run out of spare adapters, cycled power to the remote 1771 rack.
• June 28: One of the earlier replaced 1771 ASB adapter was replaced again after the whole channel went down again.
We are unsure why these modules are going bad or what is going bad in them as we don't have a way to test them. The only eye catching thing I could see is that some of the adapters are having some high numbers of reties on channel. Not sure if this is something that I should be concerned about.
Please advice.