Hello,

I want to use  aDI 16x24VDC HF_1 card and connect a signal from a servo drive wich gives 30 pulses a revolution.

my question is how to create a program wich can read this signal so i can manage the outputsignal to the servodrive.

i use a s7-1511 plc and selected the option counterconfigration on the card.

fubatchi

Hello,

I want to use  aDI 16x24VDC HF_1 card and connect a signal from a servo drive wich gives 30 pulses a revolution.

my question is how to create a program wich can read this signal so i can manage the outputsignal to the servodrive.

i use a s7-1511 plc and selected the option counterconfigration on the card.

Hello.

You are not mentioning what the rotation speed is. Assuming 3000rpm with 30 pulse per revolution is 1500 pulse/second. Or 0.67ms per pulse.

You could use a time drive interrupt OB. But you will have to look if the card can handle it, and the filtering needs to be switched off.

qwazee

 

fubatchi

Hello,

I want to use  aDI 16x24VDC HF_1 card and connect a signal from a servo drive wich gives 30 pulses a revolution.

my question is how to create a program wich can read this signal so i can manage the outputsignal to the servodrive.

i use a s7-1511 plc and selected the option counterconfigration on the card.

Hello.

You are not mentioning what the rotation speed is. Assuming 3000rpm with 30 pulse per revolution is 1500 pulse/second. Or 0.67ms per pulse.

You could use a time drive interrupt OB. But you will have to look if the card can handle it, and the filtering needs to be switched off.

 And also take notice, that the PLC cycle time is probably higher that the incoming pulse interval is, so the PLC might not "catch" all pulses. Does your input card have any HSC's (High Speed Counter inputs)?

The Card Has a option called counter configuration wich is only for input 0 and 1.

in the first post is a photo from this screen.

the maximum fq what the card can handle is 3khz and the drive wil not put out more then 2khz.

so i think this wont be a problem.

i tried to use technology objects but it's not suported without the use of a special encoder-card.

since i need to connect 8 servo's to the plc i want  to use 4 normal cards and use the rest for normal I/O.

Hello

fubatchi

The Card Has a option called counter configuration wich is only for input 0 and 1.

in the first post is a photo from this screen.

the maximum fq what the card can handle is 3khz and the drive wil not put out more then 2khz.

so i think this wont be a problem.

i tried to use technology objects but it's not suported without the use of a special encoder-card.

since i need to connect 8 servo's to the plc i want  to use 4 normal cards and use the rest for normal I/O.

Using the special counter cards is the best solution. Connecting 8 fast counters is not a nice thing with normal IO.

The workaround is not recommended but looks as follows:

1) Create a "cyclic interrupt". Set the interrupt time to 200us.


2) Create code that will track the counting. The inputs needs to be addressed differently, using the    :P   as postfix. A coding idea could be:

if ("iTrigger1":P <> "oldTrigger1")
then // DETECT CHANGE OF INPUT STATE
  "counter1" := // M-memory tag assigned as DINT
  "counter1" + DINT#1;
end_if;

"oldTrigger1" := // M-memory tag assigned as BOOL
"iTrigger1":P;

3) Download hardware and software. Check if the system works.

This code is repeated every 200us and has the potential of crippling the system. The higher the time value is, the less influence on the PLC system.

Special hardware does not tax the PLC main processor.

The S7-1200 is a nice option because it has built-in high speed counters... but not 8 of them. The CPU1511C would also be a good alternative for you for having built-in IO that can handle high speed counting.