ENGR: SPPA-T1000 compared with SPPA-T3000

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------------ Forwarded Message ------------
From: Robin Ray
To: AUTOMATION at CONTROL.COM
Subject: Re: ENGR: SPPA-T1000 compared with SPPA-T3000

Deejay,
(1)We are getting supply of big steam turbines from Siemens together with SPPA-T3000. We do not trust reliability of single ring bus. Please tell where Siemens has supplied double ring bus so that we can also demand for it.

(2)Your view point on battery backup is technically not correct. Battery backup CPUs were used in early DCS and even now in some PLC. Nowdays,non volatile memories are used. They do not require battery back up because memory data never gets lost. CPUs of modern and good DCS do not require battery for back up. If Siemens uses battery backup, it means that SPPA-T3000 is nothing more than a decorated PLC. 

This brings one more point. Siemens is big company and  can force customer to take SPPA-T3000 with turbines. Otherwise, no guarantee. Why customer has no choice to evaluate and choose other Siemens DCS like PCS7, Teleperm XP, T1000 or T2000? We want to discuss this in ISA meeting.

On Jul 23, 2008 3:10 am, Deejay wrote:
I do not agree with some of your observations against Siemens SPPA-T3000.

(1) If you want, Siemens can supply you T3000 with dual ring data highway. But redundancy is always a waste of engineering effort and money. To keep your CAPEX (capital expenditure) low, you should take single ring.

(2) Battery-backed CPU is good feature of SPPA-T3000. The battery saves CPU memory during transport, storing, shutdown and power failure. Siemens therefore gives us battery backup for CPU to protect our data. Other systems like SPPA-T1000 and from other companies do not give this feature.

( Complete thread: http://www.control.com/thread/1026244939 )