AB9900 possible register overflow

Anybus Support
#25

Hi Kyle,

We are still not getting the proper values

Issue 1 – Modbus PLC address 4001 maps to ANYBUS 3, Modbus PLC address 4003 maps to ANYBUS 5 etc… not a big deal but strange

Issue 2 – Example Modbus PLC address 4001 value 4.68, ANYBUS 3 value 4.12 and affects ANYBUS 5 value 0.1

Issue 3 – Tried many different settings, address 1, 5, 9 , 16 bit, 32 bit, 48bit, 64 bit, big endian, little endian, tried reading input registers, swapping byte order, map value 16 bit two consecutive Modbus registers etc…

Same problems are still on going, I can’t tell if there are error messages in Modbus tho

#26

In modbus this is common for an offset of +/-1, but to have an offset of 2 is different. Is it possibly due to a control/status word?

I’ve never seen an issue like this with the AB9900, so I think it may be related to your Modbus device. Do you have access to the memory map for the PLC? Is it possibly a translation between hex and decimal that is throwing everything off?

#27

Kyle,

Would you be able to see this link?

https://cdn.automationdirect.com/static/manuals/p2userm/ch6.pdf

Page 6-22 (CPU Modbus Tag format and addressing ranges)

There is more information in pages 6-20 to 6-28 regarding our CPU Modbus format, perhaps might help us is our devices are compatible at all?

image001.png837×904 166 KB

image002.png679×872 174 KB

#28

HI Cesar,

I’m sorry, but it’s been a busy day here. I have had a chance to review the documents and this PLC is a very powerful and configurable Modbus device, so I’m sure it can be configured to work with the AB9900. What I think is happening is a mismatch somewhere between the data type, number of bytes, etc. that is causing certain registers to overflow into others. It is just going to take a lot of trial and error to make sure that your integers or floats match up exactly between the PLC and the gateway. I am pretty confident that this is the issue here.

Kyle

#29

Kyle,

I’m about to give up using the gateway.

I’ve tried so many changes configuring Anybus or my PLC…

So far, trying different configurations, I either

  •      Don’t get any values

  •      Values are all scrambled

  •      Decimal point affects two consecutives registers.

Not sure what I’m doing wrong?

Is there any diagnostics you can run to know if the gateway and the PLC are going to be able to used Modbus RTU properly?

We usually buy 30 gateways a year (but my recent clients are asking us to used a BTL certified unit) being this the reason I picked Anybus, hope we can make it work…

Thank you…

#30

Cesar,

You could troubleshoot using Modbus simulator software (like from http://simplymodbus.ca), but I don’t think this is the problem, they are both using Modbus RTU. The problem is the configuration. I don’t have this PLC here to test with the AB9900 however. In order to be able to offer efficient support in this case I will need to either work on this over Teamviewer or have you send a PLC to us to test with the AB9900.

If you want to do the Teamviewer please let me know when a good time to call would be, or call me at 312-893-5636, between 0800 and 1700 EST.

Kyle

#31

Kyle,

TeamViewer would be awesome, would 11:00 am work for you? The time here is 10:14am

I have the PLC and the ANYbus Gateway connected,

I’ll get TeamViewer ID and access code ready if you have time this morning?

Please advise

#32

11:00 today is good.

#33

ID

#35

Hi Cesar,

Very good working with you on this today! I hope it will be a success and we can continue working together in the future. Please do not hesitate to email or call if you have any issues or questions, or to let me know if you are going to be on-site doing the install.

Kyle

  • Worked over Teamviewer and was able to get the values to match after disabling word swap on both devices and offset registers -1 on the Anybus
#36

Thanks Kyle,

Great Work today.

Cesar Martinez

#37

Kyle,

One more question regarding the AB9900.

Can this be configured for BACnet MSTP as well as BACnet IP?

If yes, how can I see the MSTP values?

For the BACnet IP I’m using a free BACnet explorer that allows me to scan the network and see how the data goes out…

Thank you

#38

Hi Cesar,

Yes, this can be configured for BACnet MSTP. Go to the Configuration tab, BACnet Server settings, and under Gateway Mode switch from IP to MSTP:

image
image756×629 17.3 KB

All the MSTP settings are right there.

Kyle

#39

Super!

Is there a free software “MSTP” scanner I can use to see data going out?

Thank you

#40

The Diagnostics page for the AB9900 shows the data going out, but there is also a free BACnet explorer called YABE which may or may not work for you:

#41

Topic closed due to inactivity.