Direct Logic/ Stepper motor shuttle

[jtysver]

I lost a direct logic 405 cpu on a piece of equipment and had no backup but had another piece of equipment that was basically identical. I placed a new plc into the machine and uploaded the program from the other machine to see if it was possible the two programs were identical. They only have one difference to them. The stepper motors that shuttle a guide back and forth is the only difference I see so far. When I installed the new program, the shuttle did not go to the end location is was suppose to go to. I have a dv operator interface with stop, speed and jog on there. The stop was initially set at 5300 and now when I turn it to 9999 it still does not quite shuttle to the required location. I need to know how to change the stepper count in the program. Please help.

 

[NACarnes]

This may be a shot in the dark, but it sounds like your v-memory location in the operator panel under 'stop' is not the same as the intended v-memory location used in the control program. ie... V2000 (oper interface) Not = to V2002 (plc program). This is only true if you are using the PLC to directly control the stepper drives. Are you using a CTRIO card, or a different way? If so, check the tag location under the 'stop' set point, and be sure that the same location (Vxxxx) is what the control program is looking for as a stop point. You may have to follow the math within the program. This will be tricky if your only program source is what you pulled from the other controller. Your best bet is to find a hard or soft copy of the program, which has all the labels. Good Luck!

 

[NACarnes]

PS... IF THIS IS YOUR ISSUE... BE SURE TO CHANGE THE 'STOP' SET POINT BACK TO A LESSER VALUE, BEFOR PROVING OUT!!! Doing so will most likely prevent a stepper motor CRASH!!! And prevent machine damage! Again, Good Luck!

 

[NACarnes]

Let us know what you find and how you solved it! Another thing to look at is the memory location value interpritation... ie. BCD, Dec, Hex, ETC... If you don't change the program, other than the v-memory value(in either the oper panel, or PLC) this shouldn't be an issue. But due to the fact that DirectLogics can simply do math in BCD or REAL values, it is common that oper input is usually done in BCD. The CTRIO cards, however, have to have a DECIMAL input, so converting is done within the control program. EXAMPLE... oper input = V2000 in BCD / x + - 'other values' (V2002 or K or R #'s) = V2004 converted to DECIMAL or Binary V2006... So, what I am trying to say is, the V-location you enter on the oper panel will most likely be different to the location actually used to control the CTRIO. But, will be linked through math and coversion. Hope I haven't confussed you! the manuals and tech staff at AutomationDirect, are awesome at helping!

 

[jtysver]

I was unsuccessful in correcting the program so I had to buy another. The differences I saw were as follows. Maybe you can make more sense than I can out of it.
Program 1- -Program 2
LDD- -LDD
K80074000- -K8008300

LDD- -LDD
K2000- -K3000

T32- -T32
K20- -K3

Let me know if you can make any sense out of this minimal information.
thanks for your help.

 

[NACarnes]

"LDD- -LDD
K80074000- -K8008300

LDD- -LDD
K2000- -K3000"

I would need to know more about the 'OUTD' cammand, but it looks as if this may be some of the math used in the conversion. If the rest of the program ran fine, this is most likely the issue. As you are probably already familiar with, the 'K' initiates a number string in a BCD fassion, and in this case may be loaded as a multiplier or factor in the math of the motor location. As I said, I would need to see more of the programs to be sure. Glad you got it going! Hope you got a hard and soft copy of that program! Also, I would back up and save all other programs running in your plant... JUST IN CASE! Best Regards!

 

[jtysver]

Thank you very much. Our software engineer did back up a copy, or so he thought, but when we went to place it into the new PLC there was no logic saved. I personally backed it up this time saving it to a CD, placing a file on our server, and also printing off a copy of the logic in case all else fails. It may be a little extreme but better safe than sorry. I'll request that he revisits all of his backup files throughout the facility. thanks again.

 

[PLCRookie]

"LDD- -LDD
K80074000- -K8008300

LDD- -LDD
K2000- -K3000"

I would need to know more about the 'OUTD' cammand,quote]

"OUTD" Output Double(Word)
Used to output(load)two consecutive data words (16 bit+16 bit)(ie V4000 & 4001).

 

[NACarnes]

You are very welcome!... And PLCRookie, I know what 'OUTD' is, what I was trying to say was, I would need to see where the 'OUTD' pointed, and where else in the program ladder it was used, in order to fully grasp jtysver's machine trouble. It was 'LOADD'ing values, and putting them somewhere, I was refering to 'where?' But thanks for helping!