Can't connect to S7-1500 CPU while its on bus from laptop

Hello,

I currently have TIA Portal v16.1. I am able to connect to the CPU and download/go online on the PLC when I just connect to the CPU by itself. However, when I hook the CPU onto the bus along with input/output/analog input/analog output modules (22 cards in total), I am no longer able to connect to it.

At first, I got a red power fail error on the CPU. I fixed a few minor mistakes in my device configuration, unhooked the CPU so I can redownload to it, and put it back on the bus, the error disappeared. But I still cannot connect to the PLC while the CPU is on the bus. The CPU just displays "connecting..."while repeating a cycle of ~25 yellow led flashes then ~10 red led flashes. Theoretically, our 24V, 20A external power supply should be more than enough to power the bus and the rest of the machine so I doubt it's an underpower issue. 

Attached below is my device configuration. Any help would be great. Thank you. 

Use the online TIA Selection Tool ( TIA Selection Tool | Totally Integrated Automation (TIA) | Siemens Global ) and populate the PLC rack with your exact components.

It will suggest a power module (PM) to be placed somewhere in the midst of all that IO to provide enough power for the communications BUS.

JN7

Hello,

I currently have TIA Portal v16.1. I am able to connect to the CPU and download/go online on the PLC when I just connect to the CPU by itself. However, when I hook the CPU onto the bus along with input/output/analog input/analog output modules (22 cards in total), I am no longer able to connect to it.

At first, I got a red power fail error on the CPU. I fixed a few minor mistakes in my device configuration, unhooked the CPU so I can redownload to it, and put it back on the bus, the error disappeared. But I still cannot connect to the PLC while the CPU is on the bus. The CPU just displays "connecting..."while repeating a cycle of ~25 yellow led flashes then ~10 red led flashes. Theoretically, our 24V, 20A external power supply should be more than enough to power the bus and the rest of the machine so I doubt it's an underpower issue. 

Attached below is my device configuration. Any help would be great. Thank you. 

 Yes, I was able to figure out the issue last week. I placed a system power supply in the beginning of the bus on the TIA Selection Tool and it worked. 

Thank you!

0_Einstein

Use the online TIA Selection Tool ( TIA Selection Tool | Totally Integrated Automation (TIA) | Siemens Global ) and populate the PLC rack with your exact components.

It will suggest a power module (PM) to be placed somewhere in the midst of all that IO to provide enough power for the communications BUS.

JN7

Hello,

I currently have TIA Portal v16.1. I am able to connect to the CPU and download/go online on the PLC when I just connect to the CPU by itself. However, when I hook the CPU onto the bus along with input/output/analog input/analog output modules (22 cards in total), I am no longer able to connect to it.

At first, I got a red power fail error on the CPU. I fixed a few minor mistakes in my device configuration, unhooked the CPU so I can redownload to it, and put it back on the bus, the error disappeared. But I still cannot connect to the PLC while the CPU is on the bus. The CPU just displays "connecting..."while repeating a cycle of ~25 yellow led flashes then ~10 red led flashes. Theoretically, our 24V, 20A external power supply should be more than enough to power the bus and the rest of the machine so I doubt it's an underpower issue. 

Attached below is my device configuration. Any help would be great. Thank you.