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s:4/0 bit micrologix1500


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#1 rogeliososa

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Posted 21 September 2005 - 10:32 AM

I ned to know what fraction of time has the bit s:4/0 in the CPU LRP of micrologix1500.

Thanks.

#2 TConnolly

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Posted 21 September 2005 - 11:11 AM

If you will open the processor file to the main tab you can see the contents of the S:4 word. If you will click the help button from the main tab, it will tell you that S:4, the free running clock, is incremented every 100uS.

S:4/0 changes state every 100uS.
S:4/1 changes state every 200uS
S:4/2 changes state every 400uS
and so on.

This is convered in detail in your manual.

If you do not have the manuals, you can download them from www.ab.com -> follow the literature online link.

Edited by Alaric, 21 September 2005 - 11:12 AM.



#3 jhorejs

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Posted 21 September 2005 - 11:26 AM

Point of Information:

If you are using a program for a SLC500 processor and you copy it for a Micrologix application in RS Logix 500, be sure to check the status bit you are using under "free running clock".

I usually use S:4/4 as a flasher in a SLC. Last time I used this bit for MicroLogix, the thing flashed much, much faster. Dang near wore out a relay output before I realized the problem.

In summary, the same designated bits in the free running clock in SLC500 are different from the MicroLogix's.

#4 daiflying

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Posted 21 September 2005 - 11:29 AM

First Pass S:1/15

Can be Yes or No. When the controller sets this bit it indicates that the first scan of the user program is in progress.

Index Register S:24

Enter a value from -32768 to 32767. This word indicates the element offset used in indexed addressing. When an STI, high-speed counter, or Fault Routine interrupts normal execution of your program, the original value of this register is restored when execution resumes.

Free Running Clock S:4

Status Only the first 8 bits (byte value) of this word are assessed by the processor. This value is zeroed at powerup in the REM Run mode. You can use any individual bit of this byte in your user program as a 50% duty cycle clock bit. Clock rates for S:4/0 to S:4/7 are: 20, 40, 80, 160, 320, 640, 1280, and 2560 ms.The application using the bit must be evaluated at a rate more than two times faster than the clock rate of the bit. This is illustrated in the example below for SLC 5/02 and higher processors.
Dynamic Config All 16 bits of this word are assessed by the processor. The value of this word is zeroed upon power up in the REM Run mode or entry into the REM Run or REM Test mode. It is incremented every 100 microseconds thereafter.Application note: You can write any value to S:4. It will begin incrementing from this value.You can use any individual bit of this word in your user program as a 50% duty cycle clock bit. Clock rates for S:4/0 to S:4/15 are:20, 40, 80, 160, 320, 640, 1280, 2560, 5120, 10240, 20480, 40960, 81920, 163840, 327680, and 655360 msThe application using the bit must be evaluated at a rate more than two times faster than the clock rate of the bit.In the following example, bit S:4/3 toggles every 80 ms, producing a 160 ms clock rate. To maintain accuracy of this bit in your application, the instruction using bit S:4/3 (O:1/0 in this case) must be evaluated at least once every 79.999 ms.

SLC Status, Main

The status file lets you monitor how your operating system works and lets you direct how you want it to work. Depending on the type of processor you are using all of the fields explained below may not apply.

Fields on this display that are in gray are read-only. Fields shown in white are read/write. However, this information is seldom written to by the user program or programming device (unless you want to reset or clear a function). If you write to status file data, make sure that you first understand the function fully.
If you want to know how to access this display, click here.
This information appears on the Main tab with the Structured Radix selected.

What's on the Dialog?

First Pass S:1/15

Can be Yes or No. When the controller sets this bit it indicates that the first scan of the user program is in progress.

Index Register S:24

Enter a value from -32768 to 32767. This word indicates the element offset used in indexed addressing. When an STI, high-speed counter, or Fault Routine interrupts normal execution of your program, the original value of this register is restored when execution resumes.

Free Running Clock S:4

Status Only the first 8 bits (byte value) of this word are assessed by the processor. This value is zeroed at powerup in the REM Run mode. You can use any individual bit of this byte in your user program as a 50% duty cycle clock bit. Clock rates for S:4/0 to S:4/7 are: 20, 40, 80, 160, 320, 640, 1280, and 2560 ms.The application using the bit must be evaluated at a rate more than two times faster than the clock rate of the bit. This is illustrated in the example below for SLC 5/02 and higher processors.
Dynamic Config All 16 bits of this word are assessed by the processor. The value of this word is zeroed upon power up in the REM Run mode or entry into the REM Run or REM Test mode. It is incremented every 100 microseconds thereafter.Application note: You can write any value to S:4. It will begin incrementing from this value.You can use any individual bit of this word in your user program as a 50% duty cycle clock bit. Clock rates for S:4/0 to S:4/15 are:20, 40, 80, 160, 320, 640, 1280, 2560, 5120, 10240, 20480, 40960, 81920, 163840, 327680, and 655360 msThe application using the bit must be evaluated at a rate more than two times faster than the clock rate of the bit.In the following example, bit S:4/3 toggles every 80 ms, producing a 160 ms clock rate. To maintain accuracy of this bit in your application, the instruction using bit S:4/3 (O:1/0 in this case) must be evaluated at least once every 79.999 ms.

#5 Ken Moore

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Posted 21 September 2005 - 11:57 AM

MicroLogix 1200 and MicroLogix 1500: 100 μs/bit (0.0001 seconds/bit)

For example, if bit S:4/7 is monitored in an SLC 500, then that bit will be
on for 1.28 seconds and off for 1.28 seconds for a total cycle time of 2.56
seconds. If bit S:4/7 is monitored in a MicroLogix 1500, then that bit will
be on for 0.0128 seconds and off for 0.0128 seconds for a total cycle time of 0.0256 seconds.





#6 TConnolly

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Posted 22 September 2005 - 12:22 PM

Free Running Clock S:4

Clock rates for S:4/0 to S:4/7 are: 20, 40, 80, 160, 320, 640, 1280, and 2560 ms.....

This holds true for only the SLC processors where the S:4 time base is 10 milliseconds.

The ML processor it is not the case. The time base is 100 microseconds.





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