AB7634 Status Word, etc


I dialed in this morning but was asked to make a post instead.

I have a working gateway config (attached). I would like to enable the ability to read the status information (2nd screenshot) from the embedded web page on my modbus device. My understanding is I need to enable the control/status word on the modbus side (see 1st screenshot). My questions are:

  • Enabling the status word adds 2 red boxes to the memory layout. Does this insertion shift the data 2 bytes? Or does it overwrite the first 2 bytes of output from the profibus side? My config on the modbus side is shown in the 3rd screenshot. I am reading the first word at modbus register 30001. Would the status word now be at 30001 and the data that began at 30001 now be at 30002?
  • Does this setting have an effect on the profibus side? I cannot edit the siemens program, I can only edit the gateway’s config.
  • Does the status word that comes across match the value in the web page screenshot (currently 1102 in my case)?
  • Does the status word follow the rules in the final screenshot from the user manual? The value 1102 converted to binary is: [0000][0100][0100][11][1][0]. I put brackets around each section from the manual. From the manual, this would indicate to me that the general error counter should be 4 (0100 in binary) and the gateway cycle counter should be 0. But the web screenshot has 1 for both.


Gateway Config.hcg (4.0 KB)
Gateway Screenshot:

Web page screenshot:
Modbus Mapping:

Status word from manual page 9:

hms-hmsi-27-262.pdf (6.4 MB)

Hi, Sorry for the delay getting back to you on this.

Yes it will shift it automatically and the starting register and starting register of your data.

No, the Profibus side is not affected in this case.

Yes, but keep in mind that it’s in hex, not decimal.

1102 in hex is [0001] [0001] [0000] [00][1][0].

Please let me know if you have any additional questions.


FYI, I just edited my response because I was thinking of another product when I answered your first question about the data shifting when the Control/Staus Word is enabled. The data does automatically shift in this case so the starting register for your data would be 30002.

Thanks Kyle, I appreciate your assistance.

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I have another question as a part of this same installation. Is there any documentation about the control word for the AB7634, specifically a reset command via modbus? I would like to trigger a reset of the device remotely if possible. I have control/status word enabled in my config file for the modbus side.

When searching online, I found the attached documentation for an older gateway but do not see any similar documentation of the control word for this model.


Hello @clanman1,

The control/status word doc you are looking at is one dedicated to the master interface. Since the AB7634 only has slave interfaces you can refer to the anybus X-gateway generic documentation.

To reset the module with the status word enabled you can set bit 7.


Thanks for this information. One more follow up question. If I am reading the status word from the gateway at modbus register 30001, what is the address I need to write to in order to set the control word? My gateway is setup for “modbus address mode” and not “anybus” mode.

Based on page 20 of the modbus manual (https://cdn.hms-networks.com/docs/librariesprovider7/default-document-library/manuals-design-guides/hms-hmsi-27-251.pdf?sfvrsn=1c7aaad6_28), I am thinking it should be 60001.

Edit: 4xxxx is the highest I can select to write to, so I must be incorrect.

The control word takes up the first two bytes of the output buffer. The exact register will depend on the modbus addressing mode.

For modbus addressing mode this is going to holding register 1 or 40001

For Anybus addressing mode this will be holding register 1025 or 41025

To help understand the offset take a look at the section labled Modbus: When 40001 Really Means 1, or 0 Really Means 1 on this site. https://www.csimn.com/CSI_pages/Modbus101.html
Simplymodbus.ca is also another useful site.