Search results for query: *

Just, pull the selector switch on the CPU down to STOP position. Wait a couple of seconds. Then push it back to RUN position. There is not many major effect of this procedure on the CPU itself. It would go through its boot-up routines, and user-define boot-up tasks (if programmed)...

Are you sure it's a "series" resistor, or is the PLC card measuring the voltage across the resistor? May the analog card of your PLC reads only voltage, not current.

A priority encoder?

Yes, you need to "upload" from the PLC to "PG". It's in the menu of Simatic Manager. Alternatively, if you can turn off the system, then you can take out the MMC and copy from there.

I do not know your question, but if you wanted suggestion for selecting the controller, then have a look at the Siemens LOGO! smart-relays. Other manufacturers also have similar products - Allen Bradley Pico, Schneider Zelio, Teco SG2, etc.

Your problem is you are sampling for 1 second only, and then extrapolating the result for 1 hour. Large steps are inevitable. Why don't you express the speed in "per second" rate, instead of "per hour"? Or you can sample over a longer period.

jeffewil, you can run the series wound dc motor with a variac and bridge rectifier. Use a fuse and a switch (or better a circuit breaker) before the variac. So the circuit is 115 Vac -> fused disconnect or circuit breaker -> variac -> rectifier -> motor

waross, the bridge itself should provide a free-wheeling path. I agree that a cap is not needed.

I know the answers, but you should ask your local Siemens about these. It's their business.

Is it a school project? If you are already using Omron CX editor for creating the ladder diagram, why not use their line of products for all your requirements?

S7-1200 CPU comes with transistor outputs, not relays. What is the complete part number of your CPU? Are you turning on/off the relays using any counters? If so, then check if the counters are reaching their maximum values.

A sixteen-core control cable will off-course be cheaper than an additional PLC. But you said you are designing a "large exterior lighting installation". Other information also indicate a fair-sized project - 800m distance between manual panel and distribution-board, multiple circuits each with...

What are your objectives for using this cable? You originally indicated that you'll connect the PLC with a PC using this. Your PLC should have an MPI port besides the Profibus DP port. This cable will connect to that MPI port. What is the part number of your S7-300 CPU?

You can increment a counter on the positive edge of the pushbutton press signal. Then compare if the counter value is odd/even.

//the device i need to operate is a servo motor at 24V Ma its fully open and 24V 40 Ma its closed// So, it's a servo-controlled valve, and the 0-40 mA is input to the error amplifier of the servo. Then the solution indicated by Skogsgurra would work fine.

//I cannot imagine that he is after a constant 24 V supply capable of delivering 0-40 mA. No, I can not.// That's fine. I just thought he MIGHT have meant that. BTW, are you familiar with any 0-40 mA device?

Dear VE1BLL, I know 4-20 mA is a signaling standard. I work with them. My concern was the OP said he wants "0-40ma 24V". The "24V" part made me wonder about actually what he wants to achieve.

Fouad, ask your manager to send you to a PLC training course. that would be the best step. If you are keen, you can learn from some online tutorials also.

topdawg, do you want to power a 24v device from your PLC output? For some reason, I thought that you were powering a device that operates at 24Vdc and consumes 0-40 mA current. If this is so, then DO NOT try this way. Use a 24V PSU.

You'll need version 2.0 for Vista, if you're using Simatic 5.4