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Old June 17th, 2021, 04:40 PM   #16
ThreatLevelMidnight
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Quote:
Originally Posted by roxusa View Post
This is how I cycle my comms, I know a lot of programmers suggest timers.
If you are not doing a lot of position/velocity changes there is no need to keep sending it you could set it up to only send it when a change is needed. You will notice I also read back the info so I can be sure the servo has the correct info before I trigger it to move. You can also set up your error bits from the messages to let you know if a servo is not communicating.
I see how you triggered the msgs now. The MG EN XIO bit turns the OTL on, and the MG DN bit Unlatches.

The advantage to doing it that way is so it's not repeating every X s like in a timer right?
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Old June 17th, 2021, 06:54 PM   #17
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I've had success with it, Like you I saw it somewhere and went with it. I have had over 20 messages running like this in one ladder and never had trouble
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Old June 19th, 2021, 10:39 AM   #18
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I've had success with it, Like you I saw it somewhere and went with it. I have had over 20 messages running like this in one ladder and never had trouble
Really appreciate the help.

For the MSG reads.... is there a need to compare the value to the sent value? Or, will this just flag the ER if it is unable to read the register?
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Old June 19th, 2021, 11:04 AM   #19
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One more....I see you moved a -1 to the P3-08 parameter. Looking at the manual for p3-08, looks like a 1 is used for Modbus, or 0 for external. Where is the -1 coming from? Just trying to understand as I had planned on the "1".
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Old June 19th, 2021, 11:27 AM   #20
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There are a lot of failsafe's I use: for example if you are changing the value in P1-15 & P1-16,(Modbus 40272 & 40273) which is the first address of the 8 address for Revolutions / Remaining counts.
I send the values needed (write msg) and verify (read msg) back to a different register in program to make sure message received. Then after trigger to move I read P0--04 & P0-05 (Modbus 40005 & 40006)to see its there.
There are other ways I'm sure but as I said this was the first one I did and
I'm running 3 axis, so I wanted to be sure.
I also monitor the digital Input PCS2-11/12/13 which sets in binary which of the 8 positions you are asking the servo to read. You could have a hard return always in
one or the positions in the servo and change to that with the Position Command selection.
There are step sequences in the Servo Controller but I write my own in PLC
and advance the steps in my sequence based of where different servos are reading back from. Lot of manual reading of the sure servo manual download from AD
This was also my first use of MODBUS
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Old June 19th, 2021, 11:43 AM   #21
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In the manual when you look at Parameter3-08
The upper bite (8-15 bits) are Modbus addresses, and the lower are hard Input like your Zip Link. By placing a 1 in the lower bite (0-7 bits)you can change from hard input to Modbus input. I dont use any hard I/O or Zip-link I do everything with a modus command
with a Msg sending however many Words(16-bits) I need. All the Modbus addresses are spelled out in the manual for each parameter. I was sending a msg of all 1's on a first pass of the PLC
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Old June 19th, 2021, 11:46 AM   #22
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I'll see if I can send an edited program so you can get some ideas from one of the axis
Attached Files
File Type: zip CE-COMMS.zip (102.0 KB, 3 views)
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Old June 22nd, 2021, 05:09 PM   #23
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Quote:
Originally Posted by roxusa View Post
In the manual when you look at Parameter3-08
The upper bite (8-15 bits) are Modbus addresses, and the lower are hard Input like your Zip Link. By placing a 1 in the lower bite (0-7 bits)you can change from hard input to Modbus input. I dont use any hard I/O or Zip-link I do everything with a modus command
with a Msg sending however many Words(16-bits) I need. All the Modbus addresses are spelled out in the manual for each parameter. I was sending a msg of all 1's on a first pass of the PLC
I see how you used the write/ready. I'll work on editing mine with some things i've learned.

What about some of the "global" type parameters (control mode direction, digital input assignments etc)? Do you just program those with the drive software or keypad?

Just forward thinking, wondering if it would make sense to send those over Modbus, though that may use up unnecessary memory.
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Old June 23rd, 2021, 06:08 AM   #24
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I just set those parameters in the drive.
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