masked move ?

tboatman

Member
T
Join Date
Jul 2004
Posts
5
Whoever programed this micrologix used this masked move to delay a lift when it reached its upper limit (reed sw.) via a "thumb roll" pot.there is a cumulitive value in it that has to be re set every so often. what I would like to do is change it so when it makes the top limit it fires a tdr. this way the operator still has the capibility to vary the amount of delay. any help would be greatly appreciated.


MVM I:0.0 00FFh N7:0
FMUL N7:1 1 N7:2
RD N7:0 N7:1
MOV N7:2 T4:1.PRE
 
I find that i mostly used masked moves when there is an input card with 16 inputs (or more) and there is a thumbwheel switch (BCD) into 4 of the inputs. Masked move the inputs that are for the thumbwheel to a channel (register) where one can read the actual BCD value. Invaluable here. The other digital inputs can then be used normally in the program.
 
So Old Pfhaart could I just delete the rung for the masked move and use one of those inputs from the tdr ?
 
So Old Pfhaart could I just delete the rung for the masked move and use one of those inputs from the tdr ?
Click to expand...

Not sure. What is a
"thumb roll" pot
Click to expand...
?

Is it like a thumbwheel switch? If so, the masked move is probably moving the data from it to a channel or register so it can be utilised.
 
You are correct it goes to 4 inputs,and the way im seeing it each click of the wheel "00 thru 99" changes the resistence and the delay to the return Sol.
 
tboatman said:
FMUL N7:1 1 N7:2


MOV N7:2 T4:1.PRE
Click to expand...

I think Bob is right here.

MVM I:0.0 00FFh N7:0 This is taking the lower 8 bits of the micrologix's input image and moving just those 8 bits to N7:0. The thumbwheel is probably wired to these inputs, with the right digit (0-9) wired to the first four and the left digit (10-90) wired the the second four.



0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0

                        |________|  |________|

                          0,10-90      0-9




MUL N7:0 1 N7:1 - This instruciton essentially copies the value in N7:0 to N7:1 but this is not the ideal way to do it in an AB. (Programmer must have been a Modicon programmer). A better way would have been MOV N7:0 N7:1. However, this rung is completely superfulous because its overwritten by the next rung, so I would just delete it.

FRD N7:0 N7:1 This converts the BCD number in N7:0 and puts in N7:1.


MOV N7:2 T4:1.PREThis moves the value set on the thumbwheel to the preset of timer T4:1.
 
tboatman said:
You are correct it goes to 4 inputs,and the way im seeing it each click of the wheel "00 thru 99" changes the resistence and the delay to the return Sol.
Click to expand...

It is not changing the resistance. The thumbwheel is an on/off device with four switches in it.

when the thumbwheel is on 0 the inputs are 0 0 0 0
when the thumbwheel is on 1 the inputs are 0 0 0 1
when the thumbwheel is on 2 the inputs are 0 0 1 0
when the thumbwheel is on 3 the inputs are 0 0 1 1
when the thumbwheel is on 4 the inputs are 0 1 0 0
when the thumbwheel is on 5 the inputs are 0 1 0 1
and so on.
 
Alaric said:
I think Bob is right here.

MVM I:0.0 00FFh N7:0 This is taking the lower 8 bits of the micrologix's input image and moving just those 8 bits to N7:0. The thumbwheel is probably wired to these inputs, with the right digit (0-9) wired to the first four and the left digit (10-90) wired the the second four.



 0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0

                         |________|  |________|

                           0,10-90      0-9




MUL N7:0 1 N7:1 - This instruciton essentially copies the value in N7:0 to N7:1 but this is not the ideal way to do it in an AB. (Programmer must have been a Modicon programmer). A better way would have been MOV N7:0 N7:1. However, this rung is completely superfulous because its overwritten by the next rung, so I would just delete it.

FRD N7:0 N7:1 This converts the BCD number in N7:0 and puts in N7:1.


MOV N7:2 T4:1.PREThis moves the value set on the thumbwheel to the preset of timer T4:1.
Click to expand...

If you delete the MUL rung (its actually MUL n7:0 n7:2) you'll need to change the last rung to MOV n7:1 t4:1.pre.
 
You're right, I mistyped that address.

Actually the best thing to do would be this:
MVM I:0.0 00FFh N7:0
FRD N7:0 T4:1.PRE

Unless there is a reason for the one scan delay in getting the TW value into the timer preset, but I can't imagine why there would need to be one.
 
Last edited:

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