LostPatrol
Guest
L
In Allen-Bradley Micrologix PLC, there is a OSR command...is there an equivalent command for the Siemens 200 or 300 series?
TIA!
TIA!
Steve Etter
Lifetime Supporting Member + Moderator
I can't speak regarding the 300, but for the S7-200, no there is not. The only thing you with it is build a single-scan timer to do the job. That technique at least is documented in the MicroWIN Help.
Steve
Steve
Mike Williams
Member
FP= Edge positive
FN= Edge negative
FN= Edge negative
Kim Gold
Member
If you are only looking for a one shot, how about creating your own.
Eric Nelson
Lifetime Supporting Member + Moderator
Kim, please learn how to crop... 
LostPatrol, I don't work with Siemens much anymore, but I KNOW I've used one-shots in a CPU312IFM. They work exactly like an A-B OSR.
From STEP7 help:
---( P )--- (Positive RLO Edge Detection) detects a signal change in the address from "0" to "1"
and displays it as RLO = "1" after the instruction. The current signal state in the RLO is
compared with the signal state of the address, the edge memory bit. If the signal state of the
address is "0" and the RLO was "1" before the instruction, the RLO will be "1" (pulse) after this
instruction, and "0" in all other cases. The RLO prior to the instruction is stored in the address.
There is also ---( N )--- (Negative RLO Edge Detection) which is the equivalent of A-B's OSF
You can use an I, Q, M, L, or D bit for the parameter
beerchug
-Eric
LostPatrol, I don't work with Siemens much anymore, but I KNOW I've used one-shots in a CPU312IFM. They work exactly like an A-B OSR.
From STEP7 help:
---( P )--- (Positive RLO Edge Detection) detects a signal change in the address from "0" to "1"
and displays it as RLO = "1" after the instruction. The current signal state in the RLO is
compared with the signal state of the address, the edge memory bit. If the signal state of the
address is "0" and the RLO was "1" before the instruction, the RLO will be "1" (pulse) after this
instruction, and "0" in all other cases. The RLO prior to the instruction is stored in the address.
There is also ---( N )--- (Negative RLO Edge Detection) which is the equivalent of A-B's OSF
You can use an I, Q, M, L, or D bit for the parameter
beerchug
-Eric
Eric Nelson
Lifetime Supporting Member + Moderator
Whoops!...
I just realized that I duplicated Mike's answer...
FP and FN are what you use when programming in STL
Sorry I overlooked that Mike... I always program in LAD unless there's something I can only do in STL.
beerchug
-Eric
I just realized that I duplicated Mike's answer...
FP and FN are what you use when programming in STL
Sorry I overlooked that Mike... I always program in LAD unless there's something I can only do in STL.
beerchug
-Eric
Lostpatrol,
---( P )--- (Positive RLO Edge Detection) and ---( N )--- (Negative RLO Edge Detection) are edge detections on teh RLO (Result of Logic Operations) and these work exactly like OSR and OSF in AB.
However, S7 has two more edge detections. These are POS and NEG and these detect the edges of one single signal , not the whole rung before it.
Kind regards,
Jean Pierre Vandecandelaere
---( P )--- (Positive RLO Edge Detection) and ---( N )--- (Negative RLO Edge Detection) are edge detections on teh RLO (Result of Logic Operations) and these work exactly like OSR and OSF in AB.
However, S7 has two more edge detections. These are POS and NEG and these detect the edges of one single signal , not the whole rung before it.
Kind regards,
Jean Pierre Vandecandelaere
Steve Etter
Lifetime Supporting Member + Moderator
jvdcande,
Thank you. I had not considered positive and negative edge detection when thinking in terms of one-shots before. Nor was I actually aware of these two commands even if I had. I will certainly them in the future.
I appreciate the information. This is one of the main reasons I like this forum...the oportunity to learn and show my ignorance before releasing the embedded smoke in my processor. I like to think that if you don't make mistakes, you aren't trying hard enough.
Thank you. I had not considered positive and negative edge detection when thinking in terms of one-shots before. Nor was I actually aware of these two commands even if I had. I will certainly them in the future.
I appreciate the information. This is one of the main reasons I like this forum...the oportunity to learn and show my ignorance before releasing the embedded smoke in my processor. I like to think that if you don't make mistakes, you aren't trying hard enough.
LostPatrol
Guest
OP
Thanks all..I will try and see if any success
TIA!
TIA!
Terry Woods
Member
- Join Date
- Apr 2002
- Posts
- 3,170
For General Info only...
If you want to latch something only until you see a particular transition (ON to OFF, or OFF to ON, or either)...
.
You can not detect a "NOT-Transition" as in...
---| NOT-P |--- or ---| NOT-N |---
That would be like "Proving a Negative"... It can't be Done!!! -- At least, not directly!
But you can do it by using a "Proxy-Bit" as indicated in the ladder above. "C1 Just_ON" and "C1 Just_OFF" are "Proxy-Bits".
"Proxy" is not to be confused with "Proximity". That is, a "Proxy" is NOT a "Proximity Switch", nor is it a "Proximity Fuse".
The "Proxy" described above is similar to those guys that vote, using your shares, at the stock-holders meeting.
If you want to latch something only until you see a particular transition (ON to OFF, or OFF to ON, or either)...
C1 C1
---| P |-------( Just_ON )
C1 C1
---| N |-------( Just_OFF )
C1
C2 Just_ON Out-1
---| |---+---| / |--------( )
|
Out-1 |
---| |---+
Assuming C2 goes OFF, Out-1 stays latched until C1 "goes" ON.
C1
C3 Just_OFF Out-2
---| |---+---| / |--------( )
|
Out-2 |
---| |---+
Assuming C3 goes OFF, Out-2 stays latched until C1 "goes" OFF.
C1 C1
C4 Just_ON Just_OFF Out-3
---| |---+---| / |------| / |-----( )
|
Out-3 |
---| |---+
Assuming C4 goes OFF, Out-3 stays latched until C1 "Transitions" either OFF or ON.
.
You can not detect a "NOT-Transition" as in...
---| NOT-P |--- or ---| NOT-N |---
That would be like "Proving a Negative"... It can't be Done!!! -- At least, not directly!
But you can do it by using a "Proxy-Bit" as indicated in the ladder above. "C1 Just_ON" and "C1 Just_OFF" are "Proxy-Bits".
"Proxy" is not to be confused with "Proximity". That is, a "Proxy" is NOT a "Proximity Switch", nor is it a "Proximity Fuse".
The "Proxy" described above is similar to those guys that vote, using your shares, at the stock-holders meeting.
lostpatrol1
Member
- Join Date
- Aug 2002
- Posts
- 67
Ok...can someone translate the follow from A-B to Seimens using OSR
From A-B:
I:0/1
----| |----------------------[OSR Storage Bit B3:0/1 Output Bit B3:0/2]
I:0/2 B3:0/2
-----| |-------|/|------------------(B3:0/3)
Can someone translate the above into Siemens?
TIA!
From A-B:
I:0/1
----| |----------------------[OSR Storage Bit B3:0/1 Output Bit B3:0/2]
I:0/2 B3:0/2
-----| |-------|/|------------------(B3:0/3)
Can someone translate the above into Siemens?
TIA!
Last edited:
Mike Williams
Member
Ab
When you say from ab to siemens, what do you mean? Statement list? Control system flowchart? Ladder?
When you say from ab to siemens, what do you mean? Statement list? Control system flowchart? Ladder?
lostpatrol1
Member
- Join Date
- Aug 2002
- Posts
- 67
I guess the ladder list for the equivalent for the OSR from A-B to Siemens
Terry Woods
Member
- Join Date
- Apr 2002
- Posts
- 3,170
I:0/1
----| |---------------[OSR Storage Bit B3:0/1 Output Bit B3:0/2]
I:0/2 B3:0/2
----| |-------|/|------------------(B3:0/3)
If indeed that is actually the way the original code is, then here's my best guess at the operation:
First line...
When Input-1 goes ON, do a One-Shot using Bit-1 of Byte-3.
(That is, turn ON Bit-1 of Byte-3 for 1 scan until this rung is examined again on the next scan.
Then turn Bit-1 of Byte-3 OFF.)
Also, while Input-1 is ON, turn ON Bit-2 of Byte-3.
I don't see that there is much difference between "Storage Bit" and "Output Bit" unless the "Output Bit" equates to an Immediate Output. But, even then, Immediatiate Output to where? Storage? It is just a bit in the B-File.
Next line...
While Input-2 is ON AND Bit-2 of Byte-3 is OFF, then turn ON Bit-3 of Byte-3.
Input-1
----| P |-----------------------( B3.1 )
You might be able to use the ON-Transition of Input-1 directly.
That is, wherever the program looks for B3.1, use the Input-1
On-Transition instead. Depends...
Input-1
----| |-----------------------( B3.2 )
Input-2 B3.2
----| |---------|/|-------------( B3.3 )
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