ry_fern
Member
Hi Guys,
Good day!
I'm currently facing a strange problem with Simatic H-System PLC. The said system is currently programmed for Boiler Controls.
Here's the problem. (please bear with me )
There are 4 remote IO connected on a redundant Profibus connection. . The problematic nodes are nodes 6 and 7.
When we actually short Input wires for DI 1 and 2 of node 6, the corresponding LED of that module lits. However, program doesn't respond. Also, module errors for Node 6 is being reported at Node 7. After troubleshooting using IO monitor of installed modules, we found out that the Input signals were written to the input modules of the next node. To make it short, Inputs in Node 6 were written in Node 7. We haven't tested node 7 yet if it will behave the same.
Also, before the problem occurred, we made some major revisions in the program and hardware including nodes 6 and 7. The reason we modify the hardware it is that in actual Profibus cable termination in the site, Node 7 comes first after node 6 and Bus Fault never goes OFF. So node 6 has its terminating resistor activated. Since we found the bus termination questionable and rerouting of Profibus cable requires more work than configuration, we decided to adjust the hardware configuration and make a full download of it including our revised program.
Download was not finished because of an error indicating "Synchronization Error" then download was aborted. We thought the problem was caused by the hardware change. So we decided to put it back and just rerout the bus cables. Rerouting of Bus cables is yet to begin until we noticed the problem. Until now, the PLC kept showing the strange problem. We've already downloaded twice but the problem is the same until production resumed.
MRES is not yet an option since the PLC is already controlling a boiler currently in production and possible download would be in the next shutdown schedule.
Does anyone here experienced this before? Any suggestion will be highly appreciated. Thank you.
Good day!
I'm currently facing a strange problem with Simatic H-System PLC. The said system is currently programmed for Boiler Controls.
Here's the problem. (please bear with me )
There are 4 remote IO connected on a redundant Profibus connection. . The problematic nodes are nodes 6 and 7.
When we actually short Input wires for DI 1 and 2 of node 6, the corresponding LED of that module lits. However, program doesn't respond. Also, module errors for Node 6 is being reported at Node 7. After troubleshooting using IO monitor of installed modules, we found out that the Input signals were written to the input modules of the next node. To make it short, Inputs in Node 6 were written in Node 7. We haven't tested node 7 yet if it will behave the same.
Also, before the problem occurred, we made some major revisions in the program and hardware including nodes 6 and 7. The reason we modify the hardware it is that in actual Profibus cable termination in the site, Node 7 comes first after node 6 and Bus Fault never goes OFF. So node 6 has its terminating resistor activated. Since we found the bus termination questionable and rerouting of Profibus cable requires more work than configuration, we decided to adjust the hardware configuration and make a full download of it including our revised program.
Download was not finished because of an error indicating "Synchronization Error" then download was aborted. We thought the problem was caused by the hardware change. So we decided to put it back and just rerout the bus cables. Rerouting of Bus cables is yet to begin until we noticed the problem. Until now, the PLC kept showing the strange problem. We've already downloaded twice but the problem is the same until production resumed.
MRES is not yet an option since the PLC is already controlling a boiler currently in production and possible download would be in the next shutdown schedule.
Does anyone here experienced this before? Any suggestion will be highly appreciated. Thank you.
