FS-8700-01_Modbus_RTU_(T28700-01) Driver Manual

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Appendix A.4. Managing Floating points with Modbus

Modbus as a standard does not support floating point formats. Many vendors have written higher level communications software to use two 16 bit registers to represent floating point or 32 bit integers. This requires conversion software on both ends of the communication channel. The FieldServer supports this function and also provides other options to resolve this issue.

Transferring non-integer values with one register

It is possible to represent values higher than 32767 using one register in one of two ways:

•Declare data arrays as type Uint16 (Unsigned integer). This will give you a range from 0 to 65535.

•Use the scaling function on the FieldServer, which will allow you to set up any range, with 16 bit resolution.

The following example shows how scaling can be achieved on the Server side of the configuration. Note that scaling can also be done on the Client side to scale down a value that was scaled up by a Modbus vendor. Further information regarding scaling can be found in the FieldServer Configuration manual.

Example :

Map_Descriptors

 

 

 

 

 

 

 

 

 

 

Map_Descriptor_Name,

Data_Array_Name,

Data_Array_Offset,

Function,

Node_Name,

Address,

Length,

Data_Array_Low_Scale,

Data_Array_High_Scale,

Node_Low_Scale,

Node_High_Scale,

SMD_AI1,

DA_AI_01,

0,

Server,

MBP_Srv_11,

30001,

200,

0,

100,

0,

10000

SMD_AO1,

DA_AO_01,

0,

Server,

MBP_Srv_11,

40001,

200,

0,

100,

0,

10000

 

 

 

 

 

 

 

 

 

 

 

This example multiplies the values in the data array by 100 (10000 on Node_High_Scale is 100X larger than 100 on Data_Array_High_Scale). This is most commonly used when the user wants to introduce values after the decimal point. For example, a value of 75.6 will be sent as 7560, which can then be rescaled by the Modbus master.

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.FieldServer.com Tel: (408) 262-2299 Fax: (408) 262-2269 Toll_Free: 888-509-1970 email: support@FieldServer.com

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FieldServer FS-8700-08, FS-8700-01 instruction manual Appendix A.4. Managing Floating points with Modbus
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FS-8700-08, FS-8700-01 specifications

The FieldServer FS-8700-01 and FS-8700-08 are advanced protocol gateways designed for seamless communication across diverse automation systems. These devices play a crucial role in facilitating interoperability between various protocols, ensuring that data can be transferred efficiently without the need for extensive reconfiguration. The FS-8700 series targets users in building automation, industrial control, and energy management sectors, offering a flexible and reliable solution for their connectivity needs.

One of the standout features of the FS-8700 series is its support for multiple communication protocols. These gateways can handle a wide range of protocols, including Modbus, BACnet, LonWorks, and DNP3, among others. This flexibility allows different devices and systems to communicate seamlessly, regardless of their original protocol. As a result, users can integrate legacy systems with newer technologies, maximizing the value of their existing investments.

The FS-8700-01 provides a single communication port, while the FS-8700-08 boasts eight ports, catering to varying needs depending on the scale of the operation. The multiple-port configuration of the FS-8700-08 makes it especially suitable for larger installations that require concurrent communication with multiple devices. Both models are equipped with an intuitive web-based interface, simplifying configuration and monitoring. This feature enhances usability, enabling operators to manage their systems remotely with ease.

Another key characteristic of the FS-8700 series is its robust design, which ensures reliability in demanding environments. The devices are built to withstand harsh conditions, making them suitable for a wide array of applications, from factory floors to outdoor installations. Additionally, the gateways support secure data transmission, safeguarding sensitive information during the communication process.

The FS-8700 series also features extensive logging capabilities, allowing users to capture and retain communication history for future analysis. This function is invaluable for troubleshooting and optimizing system performance over time. Furthermore, these gateways can be easily integrated with building management systems and analytics platforms, enhancing overall operational efficiency.

In summary, the FieldServer FS-8700-01 and FS-8700-08 are versatile protocol gateways that offer comprehensive support for multiple communication standards, ensuring interoperability across a range of applications. With their robust design, user-friendly interface, and advanced features, these devices represent a significant upgrade for any organization looking to modernize and streamline their automation systems.
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