we want to design the control system of a small plant with about 40 I/Os,

we are going to implement a plc base control system(siemens s7), do we need for a PC to configure, manage, monitor purposes with these few I/Os in control room or only a hard wired consol containing all of the needed push bottons and light indicators and alarms is sufficient?
yours sincerely

 

For configuring and programming of the PLC you need a PLC programmer which also could also be a software running on PC instead of using Siemens PG.

For the control and monitoring purposes if the outputs are of digital type a console would be sufficient.

 

I have in my factory 100 PLCs MicroLogix 1100 (Allen Bradley) to monitoring alarms and signals in my Scada system in ethernet.

Good luck.

 

Why not also use a Siemens HMI for monitoring/operator interface istead of hardwired push buttons? The HMI need not be PC based unless you are going to collect/save process data.

 

I'm not sure that you mean monitor the PLC program, as in S7 config package or SCADA/HMI So I'll cover both.

If you want to monitor and program the plc us Step 7 its up to about version 5.3

To interface the plant. (sticking to siemens equipment) You can use a simple HMI (human machine interface) out of the OP or TP series of siemens HMI. A simple PC based method is (siemens) PROTOOL. You need the Protool RT licence and config package, ita about AU$4000 for a 512 point licence. This can give you the opertunity to configure a graphical interface to your process from your PC. That way you can monitor/control the process.

Dennis

 

Dear Fahimi,

In my point of view the computer way is better because:
- if your system has to evoluate it's more easy to manage computer than hardware.
- you can have more than read/write I/Os like reports, statistics.

But if you have an application that you are sure it will never change and you don't need any "extra features"; so you can choose an hardware way !!

If you choose a software way, I propose you to evaluate our software Plantvue. This software is a Scada adapted for small applications like your.
It is cheap and easy to configure.

I suggest to contact us here:
- For Europe: http://www.arcinfo.com
- For Asia: http://www.pcvue-sea.com
- For US: http://www.pcvueinc.com

You can also contact me here: mailto:[email protected]

Hope to talk to you soon.

Nicolas

 

It depends largely on what your customer (or you) wants, does he want to monitor each actuator (valve, motor)? Does he want to monitor each sensor? Does he want to have alarm report? On such a small control system it's mostly enough to monitor the most important elements by lighting or not a lamp for example. I do not know how many outputs you have, but I guess there are about 15 outputs. You could have 15 lamps on a console to monitor each actuator. If this actuator is not operating then the culprit lies mostly in an envolved sensor or a triggered protection. A monitoring system to be run on a PC is rather expensive for such a project and it isn't worth the money and the trouble.
Have a good day!

 

Hi, I recommend you avoid the s7 300/400 series as the programming software is very expensive and uses a flaky token disc system that _WILL_ let you down when you need it most. (Although I hear that SIEMENS will soon be abandoning the Token discs ) For 40 IO use the S7-200 series, the Micro-Win software is powerfull, cheap, undongled. The only thing that this series doesn't have (yet) is a PROFIBUS master. As for HMI you have the TP177 running embedded LINUX or the CP_IT module with a built in webserver. Successful button and lamp layout on a hardwired console needs a great deal of thought about aesthetic and functional layout, I see so many machines, where the buttons are laid out on a grid, and they look like school projects. HMI is easier in this respect as GUI layout and structure are defacto standards (File > Open, Help>About usw.) . Remember that an HMI will be easier to modify if (when) the customers change their minds

Marc Sinclair
http://www.germainesystems.co.uk