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Unread October 17th, 2019, 01:40 AM   #1
ASF
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Powerflex 753 - Disable Manual Operation

Is there a way to prevent a user from putting a powerflex 753 into manual mode?

Ideally I'd like to be able to enforce it over comms (Ethernet/IP via 20-750-ENETR), but I can't find any way to do it at all so far, so I'll take whatever solutions I can get!
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Unread October 17th, 2019, 10:49 AM   #2
Lynx777
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You should be able to use Parameter 326 "Manual Cmd Mask" to enable or disable manual control.
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Unread October 17th, 2019, 03:17 PM   #3
jraef
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Note however that by default, all Stop devices remain functional, i.e. the Stop button on the keypad always works to stop the motor unless you specifically disable that.


Also, you mask the Command and the Speed Reference separately, so for example if you mask the local I/O for On/Off commands, but not the Speed reference, a local pot (or keypad) can still change speed.

Last edited by jraef; October 17th, 2019 at 03:19 PM.
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Unread October 17th, 2019, 09:58 PM   #4
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Quote:
Originally Posted by Lynx777 View Post
You should be able to use Parameter 326 "Manual Cmd Mask" to enable or disable manual control.
If I read the manual correctly, that's just to prevent different ports/devices from issuing a start/direction command while in manual mode. It doesn't prevent me from getting to manual mode in the first place, which is what I want. If someone walks past the drive and puts it in manual, I can see it in the PLC, but I've got no way of switching it back over comms. That's the situation I want to avoid.
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Unread October 17th, 2019, 10:07 PM   #5
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Quote:
Originally Posted by jraef View Post
Note however that by default, all Stop devices remain functional, i.e. the Stop button on the keypad always works to stop the motor unless you specifically disable that.
I was aware of this - although I didn't know there was a way to specifically disable the stop button on the keypad. How do I do that? I've seen parameter 919 (stop owner) but that just seems to indicate which port is currently issuing the stop command, not control which ports can issue it. This drive is an IP rated drive in an operator accessible area, and I want to remove as many avenues of interference as possible, short of removing the entire HIM (still want a local running/speed readout).

Quote:
Originally Posted by jraef View Post
Also, you mask the Command and the Speed Reference separately, so for example if you mask the local I/O for On/Off commands, but not the Speed reference, a local pot (or keypad) can still change speed.
Can you expand on masking the speed reference? I haven't found a way to mask speed references specifically. All I found was the Spd Ref A Select (parameter 545) which I intended to set to 875 (port 5, which is my 20-750-ENETR module). Then presumably I need to configure the drive to use only speed reference A, but I've not worked out how to do that specifically, other than just never selecting speed reference B or a preset speed reference. This may be what you meant - it's just not what I'd call "masking" in the same way that the logic mask seems to work, so perhaps I'm missing something.
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Unread October 18th, 2019, 06:51 AM   #6
Lynx777
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This KB article may help, https://rockwellautomation.custhelp....il/a_id/483993

A combination of parameters 324 - 327 should allow you to control which port has the ability to take control under any circumstances you want.

As to the HIM stop button, I always leave it with the ability to stop the drive unless there is some overriding reason to change it. I guess I just like the idea that I can stop the drive quickly if I'm standing there working with it.
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Unread October 18th, 2019, 06:13 PM   #7
jraef
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Sorry, I was wrong about disabling the Stop key. You can't do it on any Rockwell drives. Must have been some other brand.
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Unread October 20th, 2019, 09:19 AM   #8
Geospark
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Quote:
Originally Posted by Lynx777
...As to the HIM stop button, I always leave it with the ability to stop the drive unless there is some overriding reason to change it...
Where would you suggest we "change it"? Are you guessing there's a bit available in the Logic Mask, or somewhere else, to disable a Stop assertion?

Quote:
Originally Posted by Lynx777
...I guess I just like the idea that I can stop the drive quickly if I'm standing there working with it...
And so too does Rockwell...

586153 - PowerFlex 750 stop command will not clear a fault when the port is disabled through logic mask (HIM stop button will still stop the motor)
Access Level: Everyone

Quote:
Originally Posted by jraef
...disabling the Stop key. You can't do it on any Rockwell drives...
This is quite correct. For Safety purposes, Rockwell do not permit disabling a Stop assertion from any valid source or device port. Usually, and I stress usually, asserting a Stop should not be dangerous. However, not having the ability to Stop the driven application from say, a local source (HIM), could be dangerous. So they err more on the cautious side.

ASF,

In the Logic Mask (Parameter 324) you can set bits 1, 2 and 3 to "0" (HIM Port 1, 2 and 3) and the HIM should be prevented from issuing Logic Commands such as Start or Direction. But again, it will not disable the HIM Stop button. And, of course, it's important that we are also aware that the "Single Funtion" Fault Reset of the HIM Stop button is also disabled when the HIM port is mask disabled. But we can still use the Soft keys (ESC, CLR, etc.).

Getting to the nub of the issue...

Quote:
Originally Posted by ASF
...If I read the manual correctly, that's just to prevent different ports/devices from issuing a start/direction command while in manual mode. It doesn't prevent me from getting to manual mode in the first place, which is what I want...
Q: Does masking the HIM port disable the specific "Controls" key on the HIM for selecting Manual, Auto, Jog, Speed Ref adjust, etc.?

A: This I am not sure I remember for certain and would have to test (or you can)? However, by my reading of the manuals, all the basic functions that the HIM "Controls" key governs are selectable via the Logic Command Word (0-31) -

Bit 2 = Jog 1
Bit 4/5 = Unipolar Direction
Bit 6 = Manual

This would suggest that masking the port should also prevent the HIM from executing these functions, similar to the start and direction commands mentioned in the manual, which are of course also in the Logic Command Word.

If at all true, then the next question I'd have is does it actually disable the Control Screen from opening off the "Controls" key? This screen opening might not matter if the Logic Commands on this screen now cannot be executed because of the applied masking. However, as we know the Control Screen also gives us access to adjust the speed reference (Ref ↑ / Ref ↓). So if the screen does open, and the Logic Commands are masked, then further, we may have to look at whether we'd also need to mask the speed reference, or not?...

565344 - PowerFlex 750 Series Drives: Controlling speed reference from external HIM
Access Level: Everyone

I'll just post a snippet from that...

Quote:
Originally Posted by Technote 565344
...Ensure the Parameter 324 [Logic Mask] and Parameter 325 [Auto Mask] do not mask out the port the HIM is connected to and are trying to control the speed from...
By my reading of that, masking the HIM port in the Logic Mask would also prevent the HIM from adjusting the speed reference. So we should not also need to mask the speed reference, regardless of whether or not the Control Screen still opens.

I'm very curious to know now, either way?

Regards,
George
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Unread October 20th, 2019, 12:01 PM   #9
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To keep someone from changing to manual mode, can you just remove the HIM?

I think the fault codes are stored inside the drive, since you can see them over the network. If I recall correctly you can slide the HIM into place after a fault to see what went wrong and do your troubleshooting.

But you have to remember to bring the HIM along with you
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Unread October 21st, 2019, 08:56 AM   #10
Lynx777
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Apologies for any confusion. As has been stated, AB does not allow the HIM stop button to be disabled. Some manufactures do allow this and my previous statement about disabling it was simply my opinion in general.
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Unread October 21st, 2019, 01:10 PM   #11
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Quote:
Originally Posted by thingstodo
To keep someone from changing to manual mode, can you just remove the HIM?...
I always try to read the previous posts carefully before posting suggestions or further information. That's why I often quote previous posters to highlight certain thinking or point out what I believe has already been mentioned...

Quote:
Originally Posted by ASF
...This drive is an IP rated drive in an operator accessible area, and I want to remove as many avenues of interference as possible, short of removing the entire HIM (still want a local running/speed readout)...
This earlier statement of intent would suggest to me that removing the HIM for any period of time would not be an option here? Disabling Manual control from the HIM appears to be the preferred option.

Regards,
George
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Unread October 21st, 2019, 01:11 PM   #12
Geospark
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Quote:
Originally Posted by ASF
...Can you expand on masking the speed reference? I haven't found a way to mask speed references specifically. All I found was the Spd Ref A Select (parameter 545) which I intended to set to 875 (port 5, which is my 20-750-ENETR module). Then presumably I need to configure the drive to use only speed reference A, but I've not worked out how to do that specifically, other than just never selecting speed reference B or a preset speed reference...
I just want to explain some more of this, if I may?...

If we use Parameter 324 - Logic Mask bits to disable control for a port then this disables it globally, regardless of whether the drive is in Auto or Manual mode. The disabled port cannot issue any commands to the Logic Command (except Stop). And from the earlier technote snippet, masking a port disabled (0) in the Logic Mask also, apparently, prevents that port from automatically being assigned as the Manual speed reference. If we don't want the port globally disabled, but we do want it disabled for commanding a particular mode, for instance, then we would leave the Logic Mask bit enabled (1) for the port and look to either...

Parameter 325 - Auto Mask (Automatic Mask)

Or

Parameter 326 - Manual Cmd Mask (Manual Command Mask)

...where we can use the respective mask bits to disable ports for a specific control mode only, rather than globally. But again, if we have already disabled a port globally in the Logic Mask then the respective mask bit for this port in each of the above two parameters should be irrelevant.

For situations where we might require Manual control from a particular port, while also needing to disable certain other ports for Manual control, but still potentially use those other ports for the Manual speed reference, then we would leave all ports unmasked (1) in the Logic Mask and look to Parameters 326 - Manual Cmd Mask, and possibly Parameter 327 - Manual Ref Mask and Parameter 328 - Alt Man Ref Sel.

Example: Let's say we want Manual mode commanded over the network via port 5 with a 20-750-ENETR installed. We don’t want Manual mode to be commanded via port 1 (HIM). But also, we do want the Manual speed reference to be sourced from port 1 (HIM), and not from port 5 over the network…

In the Logic Mask, bit 5 represents port 5 which, in this case, is the 20-750-ENETR adapter. As we want this port to be able to command Manual mode, we will leave the respective bit 5 = “1”. To command Manual mode via port 5 (network), in the controller we would set bit 6 = “1” (Manual) in the Logic Command.

Next in the Logic Mask, bit 1 represents port 1, which is used for the local HIM mounted directly on the front of the drive. We could just set bit 1 = “0” in the Logic Mask, as this will mask disable this port (HIM) from being able to command Manual mode. However, by doing so, we will also disable the HIM from being able to source the Manual speed reference (technote snippet). Therefore, we must leave the respective bit 1 = “1” in the Logic Mask for port 1 (HIM).

Instead, in this case, we can look further to Parameter 326 - Manual Cmd Mask. Within this mask word, we can set the respective bit 1 = “0” for port 1 (HIM). This specifically disables port 1 (HIM) from being able to command Manual mode but will not prevent port 1 (HIM) from being selected as the Manual speed reference. Also in the Manual Cmd Mask, we must ensure that bit 5 = “1” for port 5 (network) so that the network can issue Logic Commands in Manual mode.

Next, for the Manual speed reference from port 1 (HIM), we might assume that we must look to Parameter 327 - Manual Ref Mask to decide if port 1 (HIM) should be allowed to source the Manual speed reference when the drive is in Manual mode? In thinking so, we would make sure the respective bit 1 = “1” for port 1 (HIM) in Manual Ref Mask. However, this mask word is only relevant if the respective bit 1 = “1” in the previous Parameter 326 - Manual Cmd Mask. But we have already set the respective bit 1 = “0” in the Manual Cmd Mask. In general, the respective bit in Parameter 327 - Manual Ref Mask is only checked after its respective bit (port) has first commanded the drive into Manual mode i.e. when a port is unmasked and commands Manual mode, and its respective bit in the reference word is also unmasked, then the port is automatically assigned as the source for the Manual speed reference (unless we specify otherwise – more on that in a minute).

Therefore, we do not use the Manual Ref Mask to decide if port 1 (HIM) may be used as the Manual speed reference. However, in this mask, we would set bit 5 = “0” for port 5 so that the network cannot be used as the source for the Manual speed reference. This is important because, normally, and as I’ve explained, as soon as port 5 (network) commands the drive into Manual mode, port 5 (network) is automatically assigned as the source for the Manual speed reference, once its respective bit in the Manual Ref Mask is enabled (1).

So now, back to the “unless we specify otherwise”…

Parameter 328 - Alt Man Ref Sel (Alternate Manual Reference Select)

When this parameter is set to the default value of “0”, then the port that currently commands Manual mode will automatically be assigned as the source for the Manual speed reference, once its respective bit is enabled (1) in the Manual Ref Mask. However, if we require a different port as the source for Manual speed reference, then we can set the value in this parameter to the number of the required port and this will instead force the drive to use this port as the source for Manual speed reference. In our example, we want port 1 (HIM) to be used as the Manual speed reference, so we set Alt Man Ref Sel = “1”.

Execution:

When port 5 (network) commands the drive into Manual mode via the Logic Command (bit 6 = “1”), it now has exclusive control over the Logic Command for Start and Direction, etc. As port 5 (network) is mask disabled (0) in the Manual Ref Mask, it cannot be automatically assigned as the Manual speed reference. Instead, Port 1 (HIM) is automatically assigned as the alternative source for Manual speed reference.

That is just an example to try and demonstrate some of the intricacies of configuring these parameters, while also including some masking to hopefully answer your question. But that masking was in relation to Manual mode. For Auto mode, we do not mask the speed reference. We must parameterize the source of the speed reference exclusively.

For your particular setup, however, you should not need to apply any non-default masking for speed reference. If you have no requirement for any Manual control or speed referencing from the HIM, then simply use the Logic Mask to set bit 1 = “0” for port 1 (HIM). You should then be able to ignore the other parameters mentioned with regard to disabling the HIM for Manual control/reference. If you wish, for “belt and brace”, for port 1 you could also set bit 1 = “0” in Man Cmd Mask and Manual Ref Mask, but I don’t think it is necessary once bit 1 = “0” in the Logic Mask.

For your Auto mode, if you are using port 5 (network) for control and speed reference, then you must do the following…

First we set Parameter 301 - Access Level = "2" [Expert]. This makes available the selection of the ports as the source for Parameter 545 - Spd Ref A Sel (Auto mode main speed reference). As we are using the network, then for this parameter first select Port 0 (host drive) and then select parameter 875 which represents “Port 5 Reference” (20-750-ENETR). This has now exclusively set the Auto mode speed reference to the network source. To change the source of the speed reference between the main Spd Ref A Sel value to either the Spd Ref B Sel value, or any of the available discrete Preset references (3-7), then we must either configure and switch digital inputs (3 DI & truth table), or we can use Logic Command bits 12-14 over the network (3 bits & truth table). If you do not configure either of these two methods then the drive’s Auto mode main speed reference will exclusively remain under the control of the value set in Spd Ref A Sel – port 5 (network).

As “lengthy” as that may seem. I am somewhat skipping through my explanation (interpretation) here. There are other possible things I could point out, but I am attempting to be as brief as “I” can be.

I hope that’s of some help to you, my friend?

Regards,
George
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Last edited by Geospark; October 21st, 2019 at 01:19 PM.
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Unread October 22nd, 2019, 06:44 PM   #13
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Thanks George. I've now left site, but I too am curious about whether masking the logic commands from the HIM would also mask the manual command. It does, as you mentioned, prevent fault reset from the HIM. I tried to clear a fault form the HIM and the drive told me it was not permitted - I had to clear it via comms (which was my intent, anyway).

My colleague is still onsite, so if he gets a suitable break in production I'll see if he can test it out for me!
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Unread October 22nd, 2019, 11:41 PM   #14
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No problem. You're welcome.

At a minimum, and even while the drive is running in Auto, I would press the Control key and see if the Control Screen opens or not? If it doesn't or you get another "not permitted" type message, then you are home and hosed, pretty much.

If it does open, it shouldn't do any harm if the drive is still running in Auto. Then, when you have downtime, you'd have to check if any of the functions on the Control Screen are executable, including the speed reference adjustment.

G.
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