0000088: Check what PLC does when network cables are disconnected

Network Connection Tests 1. I disconnected the ethernet cable from HalldEN2T1, which is in Backplane 0 with the PLC a. HMI lost connection, because this is the RSLinx Enterprise connection b. RSLogix5000 lost connection because RSLinx was lost. c. All I/O modules in Backplane 3 had a red light in the "OK" window indicating faulty communications 2. I plugged the ethernet cable back in a. RSLinx Enterprise reconnected automatically b. I/O modules in Backplane 3 had "OK" lights go to green c. I was able to go back "online" with RSLogix5000 3. I unplugged the ethernet cable from HalldEN2T2, which is in Backplane 3 a. All I/O modules in Backplane 3 had red light in "OK" window b. RSLogix5000 reported that the module was not connected 4. I plugged the ethernet cable back in a. I/O modules in Backplane 3 went from red to green b. RSLogix5000 reconnected with the module automatically 5. I unplugged the EWEB module a. Display screen displayed "LINK LOST" b. No other indication of failure 6. I plugged EWEB back in a. Display changed to "OK" 7. I unplugged the ethernet cable from the back of halldsc5 a. All data in HMI went blank b. No HMI control available -- nothing worked. 8. I plugged the ethernet cable back into halldsc5 a. HMI Software indicated that ethernet connectivity was restored, but HMI Control was not automatically restored b. I checked the status of the HMI Server and the RSLinx Enterprise server. HMI Server was running, but RSLinx Enterprise Server (hosted on halldsc2) was "unreachable" c. I tried to ping halldsc2 from halldsc5 and the request timed out d. I tried to ping halldsc5 from halldsc2 - I was successful e. I logged out of halldsc5 and logged in again. Tried to ping halldsc2 - unsuccessful f. I restarted halldsc5. Still unable to ping halldsc2 g. I restared halldsc2. I was able to ping halldsc2 from halldsc5 and RSLinx Enterprise came back online. 9. I unplugged the ethernet cable from halldsc2 a. HmI data went blank 10. I plugged the ethernet cable back into halldsc2 a. HMI software did not recover. It indicated that halldsc2 was "unreachable" b. Tried to ping halldsc2 from halldsc5 - unsuccessful c. Tried to ping halldsc5 from halldsc2 - successful d. Logged out and back into halldsc2 - still "unreachable" e. Rebooted halldsc2. After some time, its status changed to "Active", HMI control was restored.

Notes
(0000108) wolin (administrator) 2011-06-07 17:31	Reminder sent to: ballard Have you tried the Mantis system?

(0000109) ballard (developer) 2011-06-08 08:33	Contacted RA Tech Support with a chat (transcript attached). Bottom line - without knowing the exact nature of the network problem along with details about our network (managed/unmanaged switches, DHCP/Static IP, etc.), it is very difficult to determine what the PLC system will do. Generally, the system will try to pick up where it left off when communications were disrupted unless a fault is triggered. The fault has to be cleared by a power cycle or through the L5k software.

(0000127) ballard (developer) 2011-06-23 15:45	I went to the test lab and disconnected/reconnected various ethernet cables. A detailed description is in the attached document "Ethernet Troubleshooting.txt". In summary: PLC hardware, that is, EN2T modules and EWEB modules are robust and able to pick up where they left off when ethernet is disconnected and then reconnected. HMI computers, on the other hand, are subject to longer-lasting failures usually requiring a reboot of BOTH computers (HMI Server and RSLinx Enterprise Server) in order to restore connectivity and control.

(0000128) ballard (developer) 2011-06-23 15:47	PLC Hardware is able to recover from ethernet outage/disruption.

(0000129) wolin (administrator) 2011-06-23 16:31	"closed" hides the issue, "resolved" is better when people may want to look at it

Issue History
Date Modified	Username	Field	Change
2011-06-03 13:15	wolin	New Issue
2011-06-03 13:15	wolin	Work by outside group for Hall D	=> No
2011-06-03 13:15	wolin	Estimated man-weeks	=> 1
2011-06-03 13:15	wolin	Percentage complete	=> 0
2011-06-03 13:15	wolin	Actual man-weeks	=> 0
2011-06-03 13:16	wolin	Status	new => assigned
2011-06-03 13:16	wolin	Assigned To	=> ballard
2011-06-03 15:16	wolin	Summary	Need to check what PLC does when network cables are disconnected => check what PLC does when network cables are disconnected
2011-06-03 15:16	wolin	Summary	check what PLC does when network cables are disconnected => Check what PLC does when network cables are disconnected
2011-06-07 17:31	wolin	Note Added: 0000108
2011-06-08 08:30	ballard	File Added: Chat Session [Incident_110608-000066].pdf
2011-06-08 08:33	ballard	Note Added: 0000109
2011-06-08 08:58	ballard	Status	assigned => acknowledged
2011-06-23 15:42	ballard	File Added: Ethernet Troubleshooting.txt
2011-06-23 15:45	ballard	Note Added: 0000127
2011-06-23 15:47	ballard	Note Added: 0000128
2011-06-23 15:47	ballard	Status	acknowledged => closed
2011-06-23 15:47	ballard	Resolution	open => no change required
2011-06-23 16:31	wolin	Note Added: 0000129
2011-06-23 16:31	wolin	Status	closed => resolved

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