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cafe247, try this book: "AUTOMATING WITH STEP 7 IN LAD AND FBD, FOR SIEMENS PROGRAMMABLE CONTROLLERS TYPE S7 300/400" Author :Hans Berger. ISBN:389-578-1703 The author is (or was) a siemens engineer and has at least 3 or 4 books dedicated to Siemens Step-7. Cheers,

I suggest you to visit this site: www.plcs.net It is the biggest PLC site in the net (at least that I know of) ... surely you'll find there Omron’s PLC users. Personally I wouldn’t try to write my own protocol (except you are doing it for academic purposes). Customized communication programs...

Hi Mark, MODBUS RTU (serial) could be extremely slow depending on cable lengths and number of nodes. I wouldn’t recommend it for control (monitoring perhaps) … Unfortunately, I have not experience with Omron PLCs, so I can’t help with that … Can you please explain whether you are writing the...

This application note will also tell you what to do: http://www.yaskawa.com/site/dmdrive.nsf/DocType.html?ReadForm&Start=1&Count=1000&Expand=3 AD4014 Application Data Multiple Motor Operation

The general set up is to use PLC’s to concentrate I/P’s and O/P’s and serve as interface to field information. The HMI/SCADA should interface to these controllers and access tags (read & write) in their memory. I don’t know much about Wonderware but what I have just said apply to most of the...

The only thing you need to know is the relation between encoder revolution and linear travel. Encoders are normally coupled to machinery by pulleys, gear boxes, wheels, etc... ratio(ft/rev) x encoder(rev/pulses) x Period (pulses/sec) The period (1/frequency) can be calculated on-line by...

There are a number of things I suggest you to check: 1) Type of opto-coupler: PNP or NPN 2) Opto-coupler residual current (that is the flow of current when swithed off). 3) Opto-coupler switched ON “gate” current. 4) Minimum voltage at the “gate” (threshold) before switching off. I'm...

LionelHutz, The material handling system is for a Greenfield project(the system is being design from scratch). Thanks all for your valuable comments. Kind Regards,

furthermore: a simple program (in the interruption) will detect the pulse (rising or falling edge)and latch a flag, then ... As soon as the main program realises that the flag is ON, execute "the control action" required and at the end unlatch the flag (main program) ... then await for the...

The challenge with input pulses is to determinate how long they remain ON: 1) If they remain ON longer than the time that takes the PLC to complete one program scan, then..too easy! You just read the input in your program like you normally would do with any other digital input. 2) If the pulse...

DickDV, The loads are belt conveyors for a mine. The following data is extracted from the design data sheets: Accel Torque= 140% of FLT (full load torque) Bk/way Torque= ~90% of FLT (this is an average value) Normally these values are too high for electronic soft starters (at least for the...

Hi DickDV, I have to install 5 x 200kW 3Ø 690V AC VFDs in a transportable switchroom. Transportable switchroom dimensions are constrained by the size of roads and trucks (i.e. 5 meters width tops and 10 meters length). (2% of 200kW) x 5 = 20kW of heat is considerable. Kind Regards,

I am considering using an arrangement that allow me to control the ramp up and ramp down of a conveyor belt with a VFD whilst using a DOL starter during normal operation. I envisage the scheme to work in the following way: • Starting up will be controlled by a VFD to provide a soft-jerk-free...

Jraef, Besides we are talking about an 800 HP medium voltage (2400V AC) rotor wound induction motor, how expensive will be a soft-starter for it? I’m guessing but .. to use a soft-starter connected to the stator’s phases first I’ll have to short circuit the rotor winding (so the motor behaves...

Hi All, Thanks for the info and the attachments. jraef asked what the purpose of the starter was: its purpose is to control the torque (current) during start up. This type of motors is used to drive high inertia loads. Electricpete, Do you know whether your book (Electric Machinery Volume...

I have this old rubber mill de-commissioned about 8 years ago that we are planning to bring back to service. Its starter has been used as source for spare parts and there is not much left of it. The motor is an 800 HP 2.4kV wound rotor with slip rings and its starter used to step resistors...

I haven't used that CPU, but I have previous experience with S7-315 DP, -316DP & -318 DP ... and in those CPUs, one way to know that is when the hardware is configured through the Simatic Manager ... usually 0 is the default number for the MPI port and 1 for the profibus-DP ... give it a go...

It seems to me that there are two problems to address in your application: (1) A noisy process variable. (2) and process disturbance. 1) Noisy process variable: First I suggest you to trend the variable (most recorders can output a text like file which data can easily be manipulated with Excel)...