SLC 500 1747-L542 CPU - Not able to go online.

Rob S.

Member
Join Date
Sep 2008
Location
Maryland
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739
Good Morning ,

I have a SLC 500 rack with a 1747-L542 CPU and 2 DeviceNet scanner cards.
I am having a terrible time going online with this CPU. I am using a 1747-CP3 cable. I setup a driver with a 19200 baud rate , with a DF1 driver and still can not go online. Also , to go with RS Networx for DeviceNet , I need to go thru the CPU thru the backplane , correct ? I last time I went online via serial with a SLC 500 , I used that gray box , 1747-PIC, and that was years ago.

Thanks so much for your help. Have a great day.
 
Maybe the CH0 port is set to something else than 19200 baud, or the no of stop-bits is different or the port is not set to DF1.
Have you tried auto-configure ?
Have you investigated what Ch0 is set to in the offline project ?

You canot use the 1747-PIC (for DH485) for this PLC.
It has serial DF1 on CH0 (if not set to ASCII), and DH+ on CH1.
 
I am using a 1747-CP3 cable. I setup a driver with a 19200 baud rate , with a DF1 driver and still can not go online.

Are you using a USB adapter? also use the Auto Configure button

Here is the procedure we have for our's (CP3) that we sell its USB but if you are using a serial just leave yours to COM1 http://www.youtube.com/watch?v=QIu1AGUR4N8
 
You canot use the 1747-PIC (for DH485) for this PLC.

Why not? Channel 0 can be configured for DH485. The OP said "I used that gray box , 1747-PIC, and that was years ago." That tells me the port is configured for DH485. If this is the same PLC.
 
Mickey said:
...Channel 0 can be configured for DH485...

Quite correct. All SLC Channel 0 ports can be configured for DH-485.

Mickey said:
...The OP said "I used that gray box , 1747-PIC, and that was years ago." That tells me the port is configured for DH485. If this is the same PLC.

Perhaps Mickey, but if you look at the Rob's entire sentence...

Rob S. said:
...last time I went online via serial with a SLC 500 , I used that gray box , 1747-PIC, and that was years ago.

"a SLC 500" would not indicate to me that they mean "this" SLC and "years ago" would not mean recently to the same PLC.

I think Rob means that the last time he had to go online with an SLC 500, he had to use a 1747-PIC to do so, but that was years ago.

I keep posting this handy tip as it takes some of this guess work out of the equation...

To tell which protocol an SLC's Channel 0 is set for, unplug any cable, and watch the RS232 LED...

If it remains Off, then it is set for DF1.

If it flashes slowly then it is set for DH-485.

Once we know which protocol it's configured for we can better assist you in getting connected.

Rob S. said:
...to go with RS Networx for DeviceNet , I need to go thru the CPU thru the backplane , correct ?

The word "need" suggests that you think this is the one and only way to get on the DeviceNet network. In fact, using pass-thru from the processor to the scanner module is the least recommended method.

You would normally use a direct interface device, such as a 1770-KFD, 1784-PCD or 1784-U2DN / USB.

To use the SDNPT pass-thru driver in RSLinx Classic you must first configure the program and scanner to allow extra memory be allocated for the pass-thru driver transactions.

M File Configuration...

You must use RSLogix 500 to configure the M0 and M1 files associated with the 1747-SDN scanner. The minimum file sizes differ depending on the firmware revision of the scanner module, as follows:

Revision 4.015 361 elements
Revision 4.026 361 elements
Revision 5.01 361 elements
Revision 6.02 or higher 395 elements

You can access the M file configuration by opening the I/O Configuration within RSLogix 500, and then selecting the appropriate 1747-SDN module. The changes to the M file sizes must be downloaded to the SLC before it will work.

You must also place the SLC in Run Mode at least once before any pass-thru transactions will succeed.

Regards,
George
 
Channel Config.

General Channel 1 Driver DH+
Channel 0 System Driver DF 1 Full Duplex

Channel 1 System
Driver DH+
Baud 230.4 K

Channel 0 System
Driver DF1 Full Duplex
Baud 19200

What is the difference between Channel 1 and Channel 0 , and which channel
is key to my communication with my laptop ?

Also , once I establish communication , I can then use RS Networx for DeviceNet , correct ?

Thanks so much for all your responses.
 
Channel 1 is the top channel; there is a round 8-pin Mini-DIN and a 3-wire Phoenix Combicon style plug for the DH+ network channel.

The round plug is *not* PS/2 or SCANPort or RS-232 or AppleTalk. It is physically just wired in parallel with the 3-pin DH+ plug.

You need a special DH+ device to connect to this port; you would know if you had one. 1784-U2DHP is the modern one, and the old ones were 1784-PCMK and even 1770-KF2.

Channel 0 is the bottom channel, the DB9 style RS-232 port.

The default setting is the DF1 Full Duplex protocol at 19200 baud, as you've described. That's what you should be able to autodetect or simply connect to using RSLinx Classic and the DF1 Full Duplex driver.

The leading possibilities are (1) a bad or misconfigured USB/RS232 converter, or (2) the Channel 0 port configured for a different protocol, or (3) a bad cable or (4) a damaged port.
 
Now, RSNetworx for DeviceNet can just barely be squeezed through the DF1 connection using the 1747-SDNPT driver.

This driver is not easy to set up. You have to have specific configurations, firmware, and good fortune. And it's molasses-slow.

Folks will be happy to help set it up (and George outlined the important parts above).

But first; what are you trying to fix or change ?
 
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I have a faulted DeviceNet Scanner module. It only has two PowerFlex drives on that DeviceNet Network. Their maintenance electrician came upon a faulted
Scanner Module . He says it was flashing the fault light , and flashing 20,21,22,23,24 & 78. He said he changed the card out with a new scanner card
and now it is flashing 63 & 75. I would like to be able to drill down to the scanner module and see what is going on. When you change a DeviceNet scanner , I imagine they are plug and play , if it is the exact same one , correct ?
 
The DeviceNet scanners have a "Scan List" that is loaded into them with RSNetworx software and stored in nonvolatile memory.

This scanlist is not stored in the SLC-500 program memory. You have to use RSNetworx software to load it into a new module.

"63" "75" means "Node 63 has an empty scanlist", which makes sense if it's new out of the box and has no scanlist loaded into it. All devices come out of the box as Node 63.

The other error code you saw was error 78, indicating that none of the slave devices at node numbers 20, 21, 22, 23, and 24 were communicating with the scanner.

The usual reason is that they've been unplugged or there's a broken wire.

There would be a different error code if the network was unplugged completely (91) or there was no 24V power on the network (92).

Do you know the node numbers of those two PowerFlex drives? I wonder why there are four devices showing no comms with the scanner, if there are only two slave devices on the network.
 
Quick notes about the two-digit display:

DeviceNet node numbers are 0-63, so any number in that range is a Node Number.

The most common errors include:

72 Node not responding to I/O connection.
77 Incorrect I/O data connection size
78 Node not responding to connection establishment messages
91 "Bus Off"; CAN signals are bad
92 No 24V power on Scanner's DeviceNet port


The order of the numbers is "error code" -> "node that has the error code".

A concise summary of all the error codes is in the 1747-SDN Installation Instructions. This is my go-to reference because all A-B DeviceNet scanners use the same codes.
 
Oh Ken...the plot thickens...

Rob S said:
I have a faulted DeviceNet Scanner module....flashing 20,21,22,23,24 & 78.

Why didn't you say so? :rolleyes:

I would recommend you put back in the first 1747-SDN module. There is a good chance that it is not at fault here, at all. I would then set about figuring out what devices are actually configured on this scanner's scanlist and what devices are actually assigned to the node addresses 20 through 24.

If it is continuously displaying...

78 - 20 - 78 - 21 - 78 - 22 - 78 - 23 - 78 - 24

...then this scanner has at a minimum these 5 non communicating devices added to its scanlist. I cannot see how it suddenly just started trying to communicate with more node addresses than you reckon it's scanlist should have?

If you are positive that their is physically only the two PowerFlex drives wired to this scanner's network, then hmm???....

Unless they made more swaps than you think?

Perhaps they had swapped out the original SDN module, that was displaying "some" error(s), with some other, already used, module that had a scanlist configured with the node addresses above. This would explain the module trying to communicate with more nodes than the expected two?

Then, when that did not work, they swapped out again for another, out-of-the-box new module, which subsequently displayed error 75 - 63, which as Ken points out would be the expected error for a new and unconfigured scanner module.

That's just an "out there" theory on why you're seeing what you expect not to see. But what are you basing your assessment of their being only the two PowerFlex drives on that one specific scanner?

You originally mentioned that this chassis has two DeviceNet scanner modules. I would figure out first the physical layout of both DeviceNet networks and which devices are on which scanner's network.

If you have them, are you looking at offline configuration files for these networks in RSNetWorx for DeviceNet?

If so, how many nodes are shown between the two networks and what are the devices and their addresses?

Do the node addresses 20 through 24 show up anywhere?

You might be past some or all of this fault finding by now, but if you are still struggling, then updating us with this info will greatly help us understand what might be going on here.

EDIT: On the swapping...

Because it was thought that the modules could simply be swapped out plug-and-play style, it may also be possible that they swapped the two scanner modules around in this same chassis? The module displaying the 20-24 errors "could" belong to the "other" network?

Worth considering, I feel?

Regards,
George
 
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