The Big Kahuna
Member
I have used the TI505/565, S7-300, S7-400 PLC's. I used to work for TI years ago developing the 505 product line.
I agree with earlier posts, the S7-300/400 systems are not user friendly as is the 505 system. Since you are replacing a TI565 HBU (redundant or hot back-up) system, Siemens is most likely steering you towards the S7-417H, S7-414H or PCS7 systems. Also, the Siemens salesman will have informed you that there is a tool to convert 505 programs to S7 programs...it doesn't work very well. It doesn't recognize the PID loops, Analog alarms or special function programs. This is the makup off the content of most 505 programs. Don't plan on getting any of your existing program to convert unless it doesn't have much of the above. You will most likely have to re-write your current 505 program in S7 language.
The RBC's on the 505 systems do not have any programming. They are just the communication interface to the I/O rack. If the Siemens salesman is suggesting replacing the 565 and using your existing I/O racks, you may have to change the RBC's from the twisted pair to a Profibus RBC. This works fine with some restrictions. The profibus RBC doesn't support all of the "Special Function" 505 modules such as "Peerlink", "386ATM", maybe the "8IN/4OUT"... I can't remember without researching it. Anyhow... it's a question that you need to pose before planning your replacement.
The S7-417H is a good redundant PLC. It works as well as the 565 HBU on switching over due to a CPU failure. However, the programming environments between the 505 and S7 are radically different. Siemens offers a ladder package called STEP-7... It's very different from the TISOFT environment and unfortunately...much more difficult for someone who is a novice PLC programmer. Siemens also offers an IEC-1131 environment that provides function block style programming and sequential function charts.
If your company isn't completely hung up on Siemens... I would also suggest looking into A-B's Control Logix. The Profibus modules that you are going to need for the 505 racks will work with most any Profibus interface. You're not restricted to Siemens once the Profibus RBC's are installed. You may have to jumble your I/O mix a little due to the special function module restrictions.
I have dealt with other customers that have contemplated the same situation as yourself and have made the same recommendations.
One last question that you should pose to your Siemens salesman is that Siemens has a policy of obsoleting older releases of software. i.e. If you install a system, say, version 1.0 software... Siemens subsequently releases version 2.0...You have a problem and need support.. Siemens response has been that you need to purchase the upgrade because they don't support version 1.0 anymore. They kinda treat it like Bill Gates does with Windows.
Hope this helps.
I agree with earlier posts, the S7-300/400 systems are not user friendly as is the 505 system. Since you are replacing a TI565 HBU (redundant or hot back-up) system, Siemens is most likely steering you towards the S7-417H, S7-414H or PCS7 systems. Also, the Siemens salesman will have informed you that there is a tool to convert 505 programs to S7 programs...it doesn't work very well. It doesn't recognize the PID loops, Analog alarms or special function programs. This is the makup off the content of most 505 programs. Don't plan on getting any of your existing program to convert unless it doesn't have much of the above. You will most likely have to re-write your current 505 program in S7 language.
The RBC's on the 505 systems do not have any programming. They are just the communication interface to the I/O rack. If the Siemens salesman is suggesting replacing the 565 and using your existing I/O racks, you may have to change the RBC's from the twisted pair to a Profibus RBC. This works fine with some restrictions. The profibus RBC doesn't support all of the "Special Function" 505 modules such as "Peerlink", "386ATM", maybe the "8IN/4OUT"... I can't remember without researching it. Anyhow... it's a question that you need to pose before planning your replacement.
The S7-417H is a good redundant PLC. It works as well as the 565 HBU on switching over due to a CPU failure. However, the programming environments between the 505 and S7 are radically different. Siemens offers a ladder package called STEP-7... It's very different from the TISOFT environment and unfortunately...much more difficult for someone who is a novice PLC programmer. Siemens also offers an IEC-1131 environment that provides function block style programming and sequential function charts.
If your company isn't completely hung up on Siemens... I would also suggest looking into A-B's Control Logix. The Profibus modules that you are going to need for the 505 racks will work with most any Profibus interface. You're not restricted to Siemens once the Profibus RBC's are installed. You may have to jumble your I/O mix a little due to the special function module restrictions.
I have dealt with other customers that have contemplated the same situation as yourself and have made the same recommendations.
One last question that you should pose to your Siemens salesman is that Siemens has a policy of obsoleting older releases of software. i.e. If you install a system, say, version 1.0 software... Siemens subsequently releases version 2.0...You have a problem and need support.. Siemens response has been that you need to purchase the upgrade because they don't support version 1.0 anymore. They kinda treat it like Bill Gates does with Windows.
Hope this helps.