ab 1746-qs vs. 1746-qv?

any one familiar with these 2 AB ldt control modules, ab 1746-qs vs. 1746-qv. if so i would like to chat with ya on yahoo messenger or by phone if possible.

I am very familiar with the 1746 QS

You could say I know it inside and out. The QV is something I just spent only about 15 minutes with. Why not ask the questions here?

well i guess my situation is this. i am developing a setworks system for a sawmill. the setworks advances a log 2" or 4" before it slices a board off of the side of the log. other equipment at the mill uses the qs module. i dont see the need for it on what i want to do. the qs is acurate to .001" and i dont need that much acuracy, .01 is fine and the qv is capable of that. what worries me is the closed loop control vs. open loop control. i dont think i need the close loop control, but is there something i am missing or not understanding ???? thanks for your interest Peter.

open loop vs closed loop control with slc500

just trying to get a responce from my question i post a while back.
any one have any info ???

I some how missed post #3

Most applications in a saw mill need closed loop control. I think you might get by if you use the SLC PID to control the open loop output of the QV but you can do it easily with the QS. The QS has far superior diagnostics.

If you need only one axis and have a free serial port or have Ethernet ( 5/05 ), I know of other options.

I am familiar with just about everything that moves in a saw mill. What are you moving? A fence? The bigger issue is how fast can you move the cylinder and get into position. This is where the QS will excel because it has feed forwards.

thanks Pete !!! i am wanting to make a headrig setworks system. our old inovec system is about to die and we cant get parts for that model anymore. also we have the old tempo not the tempo II so i suppose we would have to upgrade to newer wands also. do you know of any online information on understanding ldt,s. i saw an old slc 150 controlling a resaw setworks at another mill once. i think it may have had a high speed counter. we are a small mill and there are lots of places i could use this technology if i understood it better. we currently have an edger that uses 2 QS modules so am learning from that.

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straydog said:

thanks Pete !!! i am wanting to make a headrig setworks system. our old inovec system is about to die and we cant get parts for that model anymore.

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I just heard that Innovec was bought by USNR. You must have the old multibus controllers that Innovec made for years.

For a headrig you definitely want to use a QS because the QS can coordinate four knees and do the tapered moves ( linear interpolation ) that headrigs require. You can't do that with a QV and only open loop. The synchronizing of four cylinders in the PLC would be a nightmare and even if you could the performance of the QVs wouldn't match the QS. The S in QS stands for synchronized. The Q is for special modules.

straydog said:

also we have the old tempo not the tempo II so i suppose we would have to upgrade to newer wands also.

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Those have been obsolete for quite a while. The new Temposonic new will be the G series. You will probably want PWM or gated rods. I would check your edger so you get the same type.

straydog said:

do you know of any online information on understanding ldt,s. i saw an old slc 150 controlling a resaw setworks at another mill once.

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I don't but the Temposonic and Balluff websites do.
http://www.mtssensors.com/
http://www.balluff.com/Balluff/

Both companies make rods compatible with the QS.

straydog said:

i think it may have had a high speed counter. we are a small mill and there are lots of places i could use this technology if i understood it better. we currently have an edger that uses 2 QS modules so am learning from that.

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The QS has a 60 MHz counter for each of its four LDT rod interfaces and uses two recirculations which means it averages two readings to get 0.001 resolution.

If you already have QS modules I would stay with that. I would also see if you get or use the same rods as your edger uses. If those rods are also obsolete then I would call the manufacturer and ask for the newest equivalent. It should make sense that keeping things as much the same as possible makes the equipment easier for you and your purchasing agent to purchase and inventory.

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