请教，大家帮我看看这个报警应该是什么原因造成的

谢谢

故事时候这样的：

一个控制器通过1个com口控制3个传感器，协议为485

－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－

Com-Port: 4. Commando: Read xxx-lyser_Info.vi. Address: 05.
Error-Code: 5002. MB Exeption Code 0x0B.
.
2010.03.09 11:40:49 Com-Port: 4. Commando: Read xxx-lyser_Info.vi. Address: 05.
Error-Code: 5002. MB Exeption Code 0x0B.
.
2010.03.09 11:40:50 Com-Port: 4. Commando: Read xxx-lyser_Info.vi. Address: 05.
Error-Code: 5002. MB Exeption Code 0x0B.
.
2010.03.09 11:40:52 System-Status: Failure
FAILURE EC
unknown on COM4, address=5. Com_Status d5002
MB Exeption Code 0x0B.

－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－-

2010.03.09 12:45:17 Com-Port: 1. Commando: 1. trail of Weckzeichen. Address: 20.
Error-Code: 5000.
2010.03.09 12:45:21 Com-Port: 1. Commando: 1. trail of Read device description.vi. Address: 00.
Error-Code: 5000.
2010.03.09 12:45:21 Com-Port: 1. Commando: 2. trail of Read device description.vi. Address: 00.
Error-Code: 5000.
2010.03.09 12:45:22 Com-Port: 1. Commando: 3. trail of Read device description.vi. Address: 00.
Error-Code: 5000.
2010.03.09 12:45:23 Com-Port: 1. Commando: 1. trail of Read device description.vi. Address: 01.
Error-Code: 5000.
2010.03.09 12:45:23 Com-Port: 1. Commando: 2. trail of Read device description.vi. Address: 01.
Error-Code: 5000.
2010.03.09 12:45:24 Com-Port: 1. Commando: 3. trail of Read device description.vi. Address: 01.
Error-Code: 5000.
2010.03.09 12:45:25 Com-Port: 1. Commando: 1. trail of Read device description.vi. Address: 02.
Error-Code: 5000.
2010.03.09 12:45:25 Com-Port: 1. Commando: 2. trail of Read device description.vi. Address: 02.
Error-Code: 5000.
2010.03.09 12:45:26 Com-Port: 1. Commando: 3. trail of Read device description.vi. Address: 02.
Error-Code: 5000.
2010.03.09 12:45:27 Com-Port: 1. Commando: 1. trail of Read device description.vi. Address: 03.
Error-Code: 5000.
2010.03.09 12:45:28 Com-Port: 1. Commando: 2. trail of Read device description.vi. Address: 03.
Error-Code: 5000.
2010.03.09 12:45:28 Com-Port: 1. Commando: 3. trail of Read device description.vi. Address: 03.
Error-Code: 5000.
2010.03.09 12:45:29 Com-Port: 1. Commando: 1. trail of Read device description.vi. Address: 04.
Error-Code: 5000.
2010.03.09 12:45:30 Com-Port: 1. Commando: 2. trail of Read device description.vi. Address: 04.
Error-Code: 5000.
2010.03.09 12:45:30 Com-Port: 1. Commando: 3. trail of Read device description.vi. Address: 04.
Error-Code: 5000.
2010.03.09 12:45:31 Com-Port: 1. Commando: 1. trail of Read device description.vi. Address: 05.
Error-Code: 5000.
2010.03.09 12:45:32 Com-Port: 1. Commando: 2. trail of Read device description.vi. Address: 05.
Error-Code: 5000.
2010.03.09 12:45:32 Com-Port: 1. Commando: 3. trail of Read device description.vi. Address: 05.
Error-Code: 5000.
2010.03.09 12:45:33 Com-Port: 1. Commando: 1. trail of Read device description.vi. Address: 06.
Error-Code: 5000.
2010.03.09 12:45:34 Com-Port: 1. Commando: 2. trail of Read device description.vi. Address: 06.
Error-Code: 5000.
2010.03.09 12:45:34 Com-Port: 1. Commando: 3. trail of Read device description.vi. Address: 06.
Error-Code: 5000.
2010.03.09 12:45:35 Com-Port: 1. Commando: 1. trail of Read device description.vi. Address: 07.
Error-Code: 5000.
2010.03.09 12:45:36 Com-Port: 1. Commando: 2. trail of Read device description.vi. Add