Register mapping. Rosemount Smart Wireless Gateway

Section 5: Host Integration

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Use global scale gain and offset?: This setting determines if a global gain and offset is applied for scaled integers or if each value has a unique gain and offset. Unique gain and offsets are found on the Modbus Mapping page.

Global scale gain: This value is multiplied to the data values for the purpose of scaling integers.

If global scaling is not selected, a gain value will be available for each separate data value on the

Modbus Mapping page.

Global scale offset: This value is added to the data values for the purpose of scaling integers. If global scaling is not selected, an offset value will be available for each separate data value on the

Modbus Mapping page.

Register mapping

Register Mapping is the process of assigning data points from wireless field devices to Modbus registers. These registers can then be read by a Modbus master or client. Modbus register mapping can be found by navigating to System Settings>Protocols>Modbus.

Figure 5-6. Modbus Register Map Page

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To add a new data point to the Modbus register map:

1.

Select Add New entry.

2.

Complete all of the table entries for the new data point (note that the entry columns may vary based on the Modbus communications settings).

Host Integration

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Section 5: Host Integration

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3.

4.

Repeat for each new data point.

Select Submit.

5.

When changes have been accepted, select Return to form.

Address: This is the Modbus RTU address used by the Gateway for this data point. It is possible to group data points assigning them the same address (i.e. all data points from the same process unit can have the same address). This column only appears if Multiple Modbus Addresses is selected on the Modbus Communications page.

Register: This is the Modbus register number used for this data value. Modbus registers hold two bytes (16 bits) of information; therefore 32 bit floats and integers require two Modbus registers. Each data point needs a unique Modbus register number, unless they are assigned different addresses. Register numbers 0-19999 are reserved for Boolean (bit, coil, binary, etc…) values. Register numbers 20000+ are reserved for floating point or integer values.

Point Name: This is a two part name for the data point. The first part is the HART Tag of the wireless field device which is producing the data. The second part is the parameter of the wireless field device.

Note

Point Name is entered as <HART Tag.PARAMETER>. Point Name can be entered using the list of values (…) or manually entered. The following table gives a list of standard device parameters which may be considered for Modbus register mapping.

Table 5-1. Device Parameters Available

Parameter Description

PV

SV

TV

QV

RELIABILITY

ONLINE

PV_HEALTHY

SV_HEALTHY

Primary Variable

Secondary Variable

Tertiary Variable

Quaternary Variable

A measure of connectivity to the Gateway

Wireless communications status

Health status for PV

Health status for SV

TV_HEALTHY Health status for TV

QV_HEALTHY Health status for QV

Data type

32-bit float

32-bit float

32-bit float

32-bit float

32-bit float

Boolean

Boolean

Boolean

Boolean

Boolean

PV, SV, TV, and QV (dynamic variables) will vary by device type. Please refer to the device’s documentation for more information on what value is represented by each dynamic variable.

RELIABILITY and ONLINE relate to wireless communications. RELIABILITY is the percentage of messages received from the wireless field device. ONLINE is a true/false indication of whether the device is communicating on the wireless network.

Host Integration

**_HEALTHY parameters are a true/false indication of the health of a particular variable (** = dynamic variable – PV, SV, etc…). These parameters incorporate critical diagnostics from the wireless field device as well as communication status.

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Note

The **_HEALTHY parameters are a great indication of the health and communications status of the data values.

State (state value): The value of a data point which drives a Modbus output of 1. For example, if a data point is reported as either True or False, a state value of True will report a 1 for True and 0 for False. A state of False will report a 0 for True and a 1 for False. State is only required for register numbers 0-19999 (Boolean, bit, coil, binary, etc…).

Invert: This check box will invert the Modbus output from a 1 to a 0 or a 0 to a 1. Invert is only used for Boolean values using register numbers 0-19999.

Gain: This value is multiplied to the data value for the purpose of scaling integers. Gain is only required if scaled is chosen on the Modbus communications page and globe gain and offset is not chosen.

Offset: This value is added to the data value for the purpose of scaling integers. Offset is only required if scaled is chosen on the Modbus communications page and globe gain and offset is not chosen.

Predefined Modbus registers

In addition to user configurable parameters, the Gateway also supports a list of predefined

Modbus registers with diagnostics and test parameters. The following table is a list of the predefined Modbus registers.

Table 5-2. Predefined Modbus Registers

Description

Current Year (1)

Current Month (1)

Current Day (1)

Current Hour (1)

Current Minute (1)

Current Second (1)

Messages Received

Corrupt Messages Received

Messages Sent With Exception

Messages Sent Count

Valid Messages Ignored

Constant Float 12345.0

SYSTEM_DIAG.HART_DEVICES

SYSTEM_DIAG.ADDITIONAL_STATUS_0

SYSTEM_DIAG.ADDITIONAL_STATUS_1

SYSTEM_DIAG.ADDITIONAL_STATUS_2

SYSTEM_DIAG.ADDITIONAL_STATUS_3

Register

49009

49010

49011

49012

49014

49015

49016

49017

49018

49001

49002

49003

49004

49005

49006

49007

49008

Data type

32-bit int

32-bit int

32-bit int

32-bit int

32-bit int

32-bit int

32-bit int

32-bit int

32-bit int

32-bit int

32-bit int

32 float

32-bit int

8-bit unsigned int

8-bit unsigned int

8-bit unsigned int

8-bit unsigned int

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