Bit Shift Instruction Help....

I have this bottling system that uses a SLC 5/04. The PLC code is using a "Bit Shift" instruction to monitor the position of the container on such machine. I looked at the program and there is an array of about 80 elements that monitor the location of the container.

I will like to know if is possible to monitor such array and determine when the last container have left the last filling station. In other words, when there are no more containers in process in the filling station.

JoseM said:

I have this bottling system that uses a SLC 5/04. The PLC code is using a "Bit Shift" instruction to monitor the position of the container on such machine.

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So far so good.

JoseM said:

I looked at the program and there is an array of about 80 elements that monitor the location of the container.

Click to expand...

So the BSL length or the range of it's bit array you are concerned with is 80 bits long?

JoseM said:

I will like to know if is possible to monitor such array and determine when the last container have left the last filling station. In other words, when there are no more containers in process in the filling station.

Click to expand...

Yes, assuming a 1 in the array represents a bottle, when all 80 bits are off then you're empty. You could put 80 XIC instructions in series, but what I would do is use EQU (MEQ if required for partial words) and whittle 'er down to about 5 or 6 of those in series to an OTE "Fill Station Empty"

I was thinking about maybe using a "CPT" instruction to add all the registers that compose the array use for the Bit Shift.

Then I could use an "EQU" instruction to turn ON an "OTE" when the value is equal to zero.

I would go with Okie's suggestion. It is more obvious, and will scan faster. It will only Scan the Rung as far as the first EQU Instruction that fails, and then move on. The CPT will have to Add all the Words for a result.

Stu....

So, what I need to add is five EQU instructions in series to scan the array?

JoseM said:

So, what I need to add is five MEQ instructions in series to scan the array?

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You would only need an MEQ if the some of the Bits in one of the Words was used for something else, and you needed to exclude those Bits. 80 Bits should be exactly 5 Words, so 5 EQU Instructions should work fine in this case.

Stu.....