Hello. Couple of weeks ago I found the video with Ultramat 6 Product Owner - Mr Florian Kirsammer, where he explain how to install additional card with Modbus rtu or TCP/IP to ultramat 6. But I cannot find any product code for Modbus TCP/IP card. Anyone can help me?

Br,

Radoslaw Wichmann

Page 9 of the CGA Series 6 brochure states that the Ultramat 6 has an RS485/Ethernet interface.
https://assets.new.siemens.com/siemens/assets/api/uuid:8b9ad75e-6320-4a86-a8c8-cc44ade818ea/PIABR-00021-0521-CGA-family-brochure.pdf

I found a Modbus/RTU (RS-485) manual dated April, 2025.
https://support.industry.siemens.com/cs/attachments/109987863/A5E54405480en_ModbusDataMap_en-US.pdf?download=true

This manual has instructions for adding the option module.

The Modbus/RTU is somewhat limited - the serial settings (baud rate, parity) are fixed and are not configurable. The slave node ID can be configured under 'Profibus'.  Note that word/byte order of floating point values is not defined.

The RS-485 appears to be 4-wire with unique driver line labels.   I've done hundreds of Modbus/RTU connections and I'd have to reach out and ask Siemens how to wire it as a typical half-duplex 2-wire unit.

There is no mention of Modbus/TCP over Ethernet and no photo of the RJ-45 connector that one would expect for an Ethernet connection.

If Modbus/RTU over RS-485 is the only available option, then a Modbus-enabled RS-485/Ethernet converter would put it on an Ethernet LAN.

Note that SITRANS Analyzer Intelligence Director (SITRANS AID IQ) software was recently introduced.  It provides sensor diagnostics.  This was probably the impetus to provide a Modbus interface.   Earlier interface protocol was a Siemens proprietary protocol (ELAN).

According to specs on this information page
https://sieportal.siemens.com/en-us/products-services/10447451?tree=CatalogTree#productInformation

the software communicates with the Siemens analyzers via Modbus TCP or ELAN (a Siemens proprietary protocol). I suspect that in the absence of an Ethernet port for Modbus/TCP, that the software communicates over RS-485, and that fact did not make it into the web page.  But the devil is in the details and the details are sparse.   

For the benefit of those who find this thread in a search for the recently introduced Ultramat 6 Modbus:

Wiring for 2-wire half duplex

I have a support request pending on how to wire this for half-duplex, 2-wire Modbus RTU because there appear to be 4 driver pins:  R_Level-N-, R_Level-P-, RD/TC-N, RD/TD-P

4-wire connections typically jumper (+) to (+), (-) to (-) for 2-wire operation, but it's not clear what the unique labeling of the driver lines represents, or how to wire a device for 2-wire Modbus operation.

Implication of Fixed termination and biasing resistors on pins 7 and 9

Termination resistors are used on the ends of an RS-485 bus network, only.  A terminating resistor installed in the middle of a daisy-chained, multidrop, RS-485 network will have faults.

Profibus DP runs on RS-485 but their DB9 connectors have a switch that enables or disables the termination/biasing circuit.

That's not what the diagram for the Ultramat 6 Modbus RTU over RS-485 shows.  See page 10, section 2.5 in the "Option card Modbus RTU for Series 6 and ULTRAMAT 23" manual at this link: https://support.industry.siemens.com/cs/de/en/view/109987863

The termination and biasing resistors are fixed, and cannot be switched off.

That means that 

- the device can only be the last or end device on a multi device, daisy chained, multidrop RS-485 bus, or
- the device can only work as the sole device on a point-to-point network with a Modbus Master
- the device cannot work on a multi-device, daisy-chained, multidrop RS-485 bus as a device that is not an 'end' or last device on the bus.

That means there's no way to connect two analyzers to the same RS-485 bus, because one of them would not be 'end' or 'last' device.

Developing an understanding of this Modbus implementation

If I get information supplementing this assessment, I will post it in this thread.

Dan

1.  Ethernet Connectivity (Modbus TCP)

I found a link that provides an overview that might shed some light:

https://sieportal.siemens.com/en-ww/products-services/10030946?tree=CatalogTree#productInformation

Be sure click on "Show more"; it is a fairly long document.

One of the graphic images, third one down, shows an Ethernet Converter connecting the analyzer RS-485 network bus to the PC.  

That leads me to believe that the CGA series of analyzers talk over an RS-485 bus and that RS-485/Ethernet converter is used to achieve Ethernet connectivity.

I cannot find any evidence of a native Ethernet port on a CGA analyzer.

Be aware that standard RS-485/Ethernet converters do not provide reliable communications with Modbus RTU because of specific timing requirements in Modbus RTU.  There is a separate class of RS-485/Ethernet converters that are designed to handle the timing requirements for Modbus RTU and those converters will specify Modbus RTU compatabiltiy.

2.  Ultramat Modbus RTU is 2-wire half duplex with optional termination/biasing connections

The first graphic on the overview document shows 3 CGA devices connected as a multidrop configuration on the RS-485 bus.

Device 2 connects only with driver lines on connector pins 8 and 3 (labeled as RD/TC-N and RD/TD-P in the Ultramat Modbus document).  That proves that the Modbus RTU is conventional 2-wire, half duplex.

Device 1 and device 3 show pins pins 9 and 7 (labeled R_Level-N- and R_Level-P-) jumpered to the driver pins to provide termination/bias resistance.   Termination/bias is used only with the devices at the two ends of an RS-485 network bus, which in this example are device 1 and device 3.

Hi. Yes, I can see Ethernet as the one of the physical layers for communication.. but did anyone see product no for additional card to Ultramat 6 with Modbus TCP/IP communication? 

So why do Siemens shows things like this on YT??

https://youtu.be/ojkhY7Kr6_8?si=SUhe2dSvXP8Vw68N

There is exactly Modbus TCP/IP additional card for CGA Ultramat series.

Thx Dan. We use Modbus TCP/IP for comm between PLC and U7. That's why I was happy to see additional card introduced by Siemens (Product Owner) for Ultramat 6. 

I can see the product but future for RTU as you described. This is of course working but needs more trick as eg. special cable and termination etc.. 

So why do the Siemens shows film like this???

https://youtu.be/ojkhY7Kr6_8?si=SUhe2dSvXP8Vw68N

Br

Radek W.

I cannot answer why Siemens does anything.  I am retired; I don't work for them.  When I was working, I was an instrumentation user.

But from the link in the video, I found a page for the Ultramat 6 that lists this:

https://sieportal.siemens.com/en-de/products-services/10028625?tree=CatalogTree#relatedProducts

(part number?)   A5E52327218

(description)  Ethernet-RS485 Converter Replacement for A5E0085232383

Assuming this is the Modbus/Ethernet card, the web page provides no associated documents for the product.  But the video says the the Ultramat 23 uses the same Modbus register map, so that's probably the case with all the analyzers; you'll have to use the Modbus RTU document for the Modbus map.