Endress+Hauser Liquiline CM44 series Operator's manual

© Copyright Dec. 2016
Supplementary documentation
Liquiline CM44x, Liquiline CM44Rx, Liquiline
CM44P, Liquiline System CA80xx, Liquistation
CSFxx
Data transmission via Modbus®
Valid as of:
Software version 1.06.04
Document: Data transmission via Modbus
First edition Dec 9, 2011
Current edition June 30, 2017
SD01189C/07/EN/04.17
Author:
Endress+Hauser
Gesellschaft für Mess- und Regeltechnik mbH+Co. KG
Dieselstr. 24
70839 Gerlingen
Germany

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Table of contents
1Note ............................................................................................................................................................4
1.1 About this manual..................................................................................................................................4
1.2 Abbreviations..........................................................................................................................................4
2Installation and wiring...............................................................................................................................5
2.1 A-, B-wire................................................................................................................................................5
2.2 Termination ............................................................................................................................................5
3Modbus Protocol........................................................................................................................................6
3.1 Specification............................................................................................................................................6
3.2 Basic principle.........................................................................................................................................6
3.2.1 General.............................................................................................................................................6
3.2.2 Modbus exception codes.................................................................................................................7
3.3 Transmission Modes ..............................................................................................................................7
3.3.1 ASCII .................................................................................................................................................7
3.3.2 RTU...................................................................................................................................................8
3.3.3 TCP ...................................................................................................................................................8
3.4 Supported Function codes......................................................................................................................9
3.4.1 FC03 Read Holding Register.........................................................................................................10
3.4.2 FC04 Read Input Register .............................................................................................................10
3.4.3 FC08 Diagnostics (only serial)......................................................................................................11
3.4.4 FC16 Write Multiple Register .......................................................................................................12
3.4.5 FC23 Read/Write Multiple Register.............................................................................................12
4Commissioning.........................................................................................................................................13
4.1 Modbus RS485 .....................................................................................................................................13
4.2 Ethernet ................................................................................................................................................14
4.2.1 Verifying the connection...............................................................................................................15
4.3 Modbus TCP..........................................................................................................................................15
4.4 Byte Order.............................................................................................................................................16
4.4.1 Integer (16 Bit)..............................................................................................................................16
4.4.2 Float / Integer (32 Bit) .................................................................................................................16
4.4.3 String..............................................................................................................................................16
4.5 Device variables ....................................................................................................................................17
4.5.1 AI –Analog input (PLCDevice) .................................................................................................17
4.5.2 Example .........................................................................................................................................18
4.5.3 DI –Digital input (PLCDevice) ..................................................................................................19
4.5.4 AO –Analog output (PLCDevice) .............................................................................................20
4.5.5 DO –Digital output (PLCDevice) ..............................................................................................20
4.5.5.1 Example: Hold over Modbus ................................................................................................21
5Diagnostics ...............................................................................................................................................22
5.1 LED displays ..........................................................................................................................................22
5.2 Status of device variables.....................................................................................................................22
5.3 Status signal..........................................................................................................................................22
5.4 Diagnostic messages ............................................................................................................................23
5.4.1 Device related diagnostics ............................................................................................................23
5.4.2 Sensor related diagnostics............................................................................................................24
5.4.2.1 Current diagnostic message .................................................................................................24
5.4.2.2 Last active diagnostic message ............................................................................................25
5.5 Communication related diagnostics....................................................................................................25
5.5.1 Bus termination.............................................................................................................................25
5.5.2 Protocol counters...........................................................................................................................25
6Applications..............................................................................................................................................26
6.1 CA80xx: How to start Measurement, Calibration and Cleaning .......................................................26
6.1.1 Activate “Fieldbus”-mode using the device menu.......................................................................28

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6.1.2 Activate “Fieldbus”-mode using Modbus.....................................................................................28
6.1.3 How-to execute actions ................................................................................................................29
6.1.3.1 How-to execute a Measurement..........................................................................................29
6.1.3.2 How-to run a Calibration ......................................................................................................30
6.1.3.3 How-to start a Cleaning........................................................................................................30
6.1.3.4 How-to abort an action.........................................................................................................31
6.1.3.5 Error evaluation.....................................................................................................................31
6.1.4 Modbus Registers..........................................................................................................................32
6.1.4.1 Analyzer Manual Actions......................................................................................................32
6.1.4.2 Analyzer manual actions state .............................................................................................33
7Appendix...................................................................................................................................................35
7.1 Data Types ............................................................................................................................................35
7.1.1 Float (IEE-754)..............................................................................................................................35
7.1.2 Integer............................................................................................................................................35
7.1.3 String..............................................................................................................................................35
7.1.4 DATETIME......................................................................................................................................35
7.1.5 Other data types............................................................................................................................35
7.2 Status codes ..........................................................................................................................................36
7.3 Unit codes..............................................................................................................................................36
7.4 Units of device variables ......................................................................................................................37
8Modbus tables..........................................................................................................................................40
8.1 Numbering of Modbus-Registers ........................................................................................................40
8.2 Factory default values ..........................................................................................................................40
8.3 General..................................................................................................................................................40
8.3.1 Identification (Input, FC: 04)........................................................................................................40
8.3.2 Process (Holding/Input, FC: 03, 16, 23, 04)...............................................................................40
8.3.3 Diagnostics (Input, FC: 04) ...........................................................................................................42
8.3.4 Configuration (Holding, FC: 03, 16, 23)......................................................................................45
8.3.5 Sensors...........................................................................................................................................47
8.3.5.1 Sensor X (Input, FC: 04)........................................................................................................47
8.3.5.2 Sensor X Setup (Holding, FC: 03, 16, 23)............................................................................52
8.4 Sampler .................................................................................................................................................53
8.4.1 Sampler (Input, FC: 04) ................................................................................................................53
8.4.2 Sampler Setup (Holding, FC: 03, 16, 23).....................................................................................54
8.5 Analyzer ................................................................................................................................................56
8.5.1 Analyzer SP 1 Info (Input, FC: 04)................................................................................................56
8.5.2 Analyzer SP 1 setup (Holding, FC: 03, 16, 23)............................................................................57
8.5.3 Analyzer SP 2 Info (Input, FC: 04)................................................................................................58
8.5.4 Analyzer SP 2 setup (Holding, FC: 03, 16, 23)............................................................................59
8.5.5 Analyzer Config (Holding, FC: 03, 16, 23) ..................................................................................60
8.5.6 Analyzer Info (Input, FC: 04) ........................................................................................................61
8.5.7 Analyzer Program (Holding, FC: 03, 16, 23)...............................................................................63
8.5.8 Analyzer Manual actions (Holding, FC: 03, 16, 23) ...................................................................64
8.5.9 Analyzer Photometer Info (Input, FC: 04)...................................................................................64
8.5.10 Analyzer Measurement data (Input, FC: 04)...............................................................................64
8.5.11 Analyzer manual actions state (Input, FC: 04)............................................................................64
8.6 Heatbeat Monitoring (requires activiation code) ..............................................................................65
8.6.1 Sensor pH (Input, FC: 04) .............................................................................................................65
8.6.2 Sensor Conductivity (Input, FC: 04) .............................................................................................66
8.6.3 Sensor Disinfection (Input, FC: 04) ..............................................................................................67
8.6.4 Sensor Oxygen (Input, FC: 04) .....................................................................................................68
8.6.5 Sensor SAC (Input, FC: 04) ...........................................................................................................69
8.6.6 Sensor CUS (Input, FC: 04) ...........................................................................................................70
8.6.7 Sensor ISE (Input, FC: 04).............................................................................................................71
8.6.8 Sensor Nitrate (Input, FC: 04) ......................................................................................................72
8.7 Calibration using the MODBUS interface (requires activation code)................................................74

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1Note
1.1 About this manual
This supplementary document must only be used in conjunction with a field device Liquiline CM44x
Modbus, an analyzer Liquiline System CA80xx Modbus or a sampler Liquistation CSFxx Modbus.
This supplementary document is an integral part of the Operating Instruction and extends it with
additional information for use with Modbus.
Additional information is contained in the following Operating Instructions:
Operating Instructions BA00444C
Operating Instructions BA01225C
Operating Instructions BA00443C
Operating Instructions BA01240C
Operating Instructions BA01570C
This document is aimed at individuals who are integrating the device into a Modbus network. It is assumed
that the reader has fundamental knowledge of Modbus technology.
Additional information about Modbus technology is available, for example, on the website:
www.modbus.org
1.2 Abbreviations
n.a. Not applicable
NaN Not a Number (IEEE-754, 7Fh A0h 00h 00h)
ENP Electronic name plate
AI Analog Input (PA Profile function block)
DI Discrete Input (PA Profile function block)
AO Analog Output (PA Profile function block)
DO Discrete Output (PA Profile function block)

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2Installation and wiring
Installation and wiring is described in detail in the operating instructions of each product.
2.1 A-, B-wire
The 485/ETH communication module uses the same connector labeling as for PROFIBUS devices. It has to
be stated that the usage of A and B is not consistent over all available Modbus devices. The 485/ETH
modules use the following definition:
Label on connector
color
signal
meaning
B
Red
RxD/TxD-P
Received/transmitted data - P
A
Green
RxD/TxD-N
Received/transmitted data - N
C
--
DGND
Data reference potential output
In case RS485 communication is not working, please verify that the RS485-signals are connected
correctly, otherwise switch the signals. Switching the RS485-signals does not damage the RS485 interface
of the device.
2.2 Termination
The communication module provides the possibility of activating a bus termination via a 4-pin DIL slide
switch. Here, the downstream Modbus devices are not separated from the Modbus RS485 segment. The
communication module must be removed to activate the bus termination. If the communication module is
installed and supplied with voltage, the bus termination state is indicated by the T LED (yellow).
The termination is according the definition for PROFIBUS DP, as the RS485 interface can be used for
PROFIBUS DP communication.
0V2
220Ω
390Ω
390Ω
B (red)
5V2
A

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3Modbus Protocol
3.1 Specification
Modbus is an open, standardized communication protocol that is used in the areas of Manufacturing,
Process- and Building automation.
The Modbus protocol is used for data exchange with intelligent field devices via master/slave
(client/server) connections. Here, the Modbus protocol can be used with different transmission media and
embedded in other communication protocols.
The specifications for the Modbus protocol are freely available on the web site of the Modbus
Organization.
http://www.modbus.org/
3.2 Basic principle
3.2.1 General
Modbus communication (unicast) uses a simple request-response mechanism.
There are three different scenarios:
If the device (server) receives a valid telegram with a valid request and is able to reply to it, it replies with a
response telegram containing the function code of the request.
If the device (server) receives an invalid telegram (e.g. CRC error), it does not reply. The application (client)
must carry out an error diagnosis once a specified time period (time-out) has elapsed.
If the device (server) receives a valid telegram with an invalid request, it replies with a Modbus exception.
The application (client) must carry out an error diagnosis.
Client/
Master
Server/
Slave
Request
Response

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3.2.2 Modbus exception codes
If the MODBUS slave detects an error in the request telegram from the master, it replies to the master with
an error message comprising the slave address, function code, error code (exception code) and checksum.
To indicate that it is an error message, the leading bit of the returned function code is set. The cause of the
error is transmitted to the master via the error code (exception code).
Exception Code
Info
01
ILLEGAL_FUNCTION
The function code sent by the master is not supported by the measuring device (slave).
02
ILLEGAL_DATA_ADDRESS
The register addressed by the master is not assigned (i.e. it does not exist), or the length
of the data queried is too long.
03
ILLEGAL_DATA_VALUE
The master attempts to write to a register which allows only read access.
The value that appears in the data field is not permitted: e.g. range limits have been
exceeded or the data format is incorrect.
04
SLAVE_DEVICE_FAILURE
The slave has not replied to the request telegram from the master, or an error has
occurred while processing the request telegram.
3.3 Transmission Modes
There are three data transmission modes: ASCII, RTU and TCP.
3.3.1 ASCII
The data are transmitted as ASCII characters and are therefore readable by humans.
Start
Address
Function
Data
LRC
End
1 character
2 characters
2 characters
N characters
2 characters
2 characters
= „:“
CRLF
Field
Length
Info
Client
Server
Address
2 Byte
Identifies the target device
Set by the client
Copied from the
request into the
reply
LRC
2 Byte
Modbus specification
Set by the client
Set by the server

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3.3.2 RTU
The data are transmitted in binary format and are therefore more compact.
Address
Function
Data
CRC16
1 character
1 characters
N character
2 characters
0 = Broadcast
247 = Unicast
A delimiter of at least 3.5 characters must be maintained between two Modbus telegrams.
Field
Length
Info
Client
Server
Address
1 Byte
Identifies target
Set by the client
Copied from the
request into the
reply
CRC16
2 Byte
Modbus specification
Set by the client
Set by the server
3.3.3 TCP
As with RTU, the data are transmitted in binary format. Address and checksum used in RTU mode are
dispensed with. The Modbus ADU is embedded in the TCP/IP telegram.
Modbus TCP/IP ADU
MBAP header
Modbus PDU
Transaction
number
Protocol
attribute
Number of
bytes
to follow
Address
Function
Data
2 Byte
2 Bytes
2 Bytes
1 Byte
1 Byte
N Bytes
= 0x0000
= N + 2
= 0
Field
Length
Info
Client
Server
Transaction
number
2 Byte
Identifies the transaction
Set by the client
Copied from the
request into the
reply
Protocol attribute
2 Byte
Set by the client
Copied from the
request into the
reply
Number of bytes to
follow
2 Byte
Number of bytes to follow
Set by the client
Set by the server
Address
1 Byte
Identifies a slave that is
connected to a serial bus
located downstream.
Note
The devices in the Liquiline
product family do not use the
unit identifier. This should
always be set to 0.
Set by the client
Copied from the
request into the
reply
Via the TCP port 502, you can use up to 3 parallel TCP connections with the device simultaneously.
Please note the correct structure of the MBAP header.

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3.4 Supported Function codes
Function
code FCxx
Name
Description
03
READ HOLDING REGISTER
Reads one or more MODBUS slave registers.
1 to maximum 125 consecutive registers can be read
(1 register = 2 bytes) with one telegram.
Application:
Reads measuring device parameters with read and write
access.
04
READ INPUT REGISTER
This function code is used to read registers with read
access. Up to 125 consecutive registers can be read.
Application:
Reads measuring device parameters with read access.
08
DIAGNOSTICS
This function code is used to check the communication
between Master and Slave.
The following sub function codes are supported:
• Sub function 00 = Return query data (loopback)
• Sub function 02 = Return diagnostic register
16
WRITE MULTIPLE REGISTERS
Describes several slave registers using a new value.
Up to a maximum of 123 consecutive registers can be
described using a telegram.
All registers that are addressed using the written registers
must be writable, as otherwise the request may be
responded to with an ILLEGAL DATA VALUE exception.
23
READ/WRITE
MULTIPLE REGISTERS
Simultaneously reads and writes 1 to maximum 118
registers in one telegram. Write permission is granted
before read permission.
Broadcast messages are permitted only with function codes 06, 16 and 23. The function code 08 is
supported only for Modbus RS485.

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3.4.1 FC03 Read Holding Register
Request
Function code
1 Byte
0x03
Starting address
2 Byte
0x0000 to 0xFFFF
Quantity of Registers
2 Byte
1 to 125 (0x7D)
Response
Function code
1 Byte
0x03
Byte Count
1 Byte
2 * Quantity of Registers
Holding register value
(2 * Quantity of Registers) Byte
2 to 250
Error
Error code
1 Byte
0x83
Exception code
1 Byte
01 or 02 or 03 or 04
3.4.2 FC04 Read Input Register
Request
Function code
1 Byte
0x04
Starting address
2 Byte
0x0000 to 0xFFFF
Quantity of Registers
2 Byte
1 to 125 (0x7D)
Reply
Function code
1 Byte
0x04
Byte Count
1 Byte
2 * Quantity of Registers
Holding register value
(2 * Quantity of Registers) Byte
2 to 250
Error
Error code
1 Byte
0x84
Exception code
1 Byte
01 or 02 or 03 or 04

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3.4.3 FC08 Diagnostics (only serial)
Request
Function code
1 Byte
0x06
Starting address
2 Byte
Quantity of Registers
N x 2 Byte
Reply
Function code
1 Byte
1 Byte
Byte Count
2 Byte
Holding register value
N x 2 Byte
Error
Error code
1 Byte
0x88
Exception code
1 Byte
01 or 03 or 04
Subfunction 0x00: Return Query Data (Loopback)
Example Request
Functionscodes
0x08
Subfunction
0x00
Data (example)
0x01 0x02 0x03 0x04
Response is identical to Request
Function code
0x08
Subfunction
0x00
Data
0x01 0x02 0x03 0x04
Subfunction 0x02: Return diagnostic register
Reads the parameter:
Parameter
Register
Bit
MB_FC08_DIAGNOSE
500
0
Sensor 1 has a diagnostic message
1
Sensor 2 has a diagnostic message
2
Sensor 3 has a diagnostic message
3
Sensor 4 has a diagnostic message
4
Sensor 5 has a diagnostic message
5
Sensor 6 has a diagnostic message
6
Sensor 7 has a diagnostic message
7
Sensor 8 has a diagnostic message
8
General diagnostic message
9..11
Reserved = 0
12
Status signal F (failure)
13
Status signal C (function check)
14
Status signal M (maintenance request)
15
Status signal S (out of specification)
The definition of the status signal complies with Namur recommendation NE107.

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3.4.4 FC16 Write Multiple Register
Request
Function code
1 Byte
0x10
Starting address
2 Byte
0x0000 to 0xFFFF
Quantity of Registers
2 Byte
0x0001 to 0x007B
Byte Count
1 Byte
(2 * Quantity of Registers) Byte
Register Value
(2 * Quantity of Registers) Byte
value
Response
Function code
1 Byte
0x10
Byte Count
2 Byte
0x0000 to 0xFFFF
Quantity of Registers
2 Byte
1 to 123 (0x7B)
Error
Error code
1 Byte
0x90
Exception code
1 Byte
01 or 02 or 03 or 04
3.4.5 FC23 Read/Write Multiple Register
Request
Function code
1 Byte
0x17
Read starting address
2 Byte
0x0000 to 0xFFFF
Quantity to read
2 Byte
0x0001 to 0x007D
Write starting address
2 Byte
0x0000 to 0xFFFF
Quantity to write
2 Byte
0x0001 to 0x0079
Write byte count
1 Byte
2 x (Quantity to write)
Write register value
2 x (Quantity to write)
Response
Function code
1 Byte
1 Byte
Byte Count
2 Byte
Data
N x 2 Byte
Error
Error code
1 Byte
0x97
Exception code
1 Byte
01 or 03 or 04
This function code can be used to read or to write the complete process data with one Modbus request.

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4Commissioning
4.1 Modbus RS485
The parameters are located in Setup/General settings/Extended setup/Modbus/Settings.
Parameter
Default value
Selection
Bus address
247
1 … 247
Transmission Mode
RTU
RTU, ASCII
Baudrate
19200
1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200
Parity
Even (1 Stopbit)
Even (1 Stopbit), Odd (1 Stopbit), None (1 Stoppbit), None
(2 Stoppbit)
Byte order
1-0-3-2
1-0-3-2, 1-0-2-3, 2-3-0-1, 3-2-1-0
Watchdog
5 s
0 … 999, 0 = Watchdog is deactivated.
If the device does not receive a valid MODBUS request
telegram, a diagnostic code S969 (Modbus Watchdog) and
the red BF LED are set. The next valid Modbus request will
remove this diagnose.
The setting of the bus address with the Address-Switch of the module has priority over the menu setting. If
a valid address is set, the bus address in the menu is read only.
Valid bus addresses are between 1 and 247. If you configure an invalid address, software addressing is
automatically enabled via the onsite setting.

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4.2 Ethernet
To ensure that a Modbus TCP connection can be established with the device, it is first necessary to adjust
the device's network settings (IP address, subnet mask and gateway). The settings depend on the network
into which the device is being integrated.
Parameter
Default value
Selection
IP-Address mode
DHCP
DHCP:
If a DHCP server is used within the TCP/IP network, the IP
address, gateway and subnet mask are set automatically when
the DHCP client function is enabled. The DHCP client function
is enabled when the measuring device is delivered. The DHCP
client function is activated by default, but can be disabled in
the "Ethernet settings" menu.
Software:
The network settings can be edited in the menu.
Hardware:
The low-byte of the IP-Address can be set with the DIP switch
located on the front of the 485/ETH module. The other parts
of the IP-Address are unchanged. This allows you to set the
higher 3 bytes using e.g. software addressing and the low-
byte by Hardware.
DHCP
On
Off, On
IP-Address
0.0.0.0
Valid IP address
Netmask
255.255.255.0
Valid Netmask
Gateway
0.0.0.0
IP-Address of Gateway (optional)
Service switch
The service switch is located on the module. While this switch
is in position “On”, the following network settings are active:
IP-Address = 192.168.1.212
Netmask =255.255.255.0
Gateway = 0.0.0.0
When returning the switch to “Off”, the original network
settings are restored.
MAC-Address
The MAC address is imprinted on the communication module
or can be read via the menu. The MAC address of the
measuring device is used for identification purposes and is
uniquely and permanently assigned in the factory.
Modbus TCP Port
502
-

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4.2.1 Verifying the connection
The measuring device implements the ICMP protocol. The "ping" command allows you to check if the
measuring device is accessible via the network.
4.3 Modbus TCP
The parameters are located in Setup/General settings/Extended setup/Modbus/Settings.
Parameter
Default value
Selection
Transmission Mode
247
1 … 247
Byte order
1-0-3-2
1-0-3-2, 1-0-2-3, 2-3-0-1, 3-2-1-0
Watchdog
5 s
0 … 999, 0 = Watchdog ist deaktiviert
If the device does not receive a valid MODBUS request
telegram, a diagnostic code S969 (Modbus Watchdog) and
the red BF LED are set. The next valid Modbus request will
remove this diagnose.

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4.4 Byte Order
4.4.1 Integer (16 Bit)
Selection
Order
1.
2.
1-0-3-2*
3-2-1-0
Byte 1
(MSB)
Byte 0
(LSB)
0-1-2-3
2-3-0-1
Byte 0
(LSB)
Byte 1
(MSB)
* Factory default, MSB = most significant byte, LSB = least significant byte
4.4.2 Float / Integer (32 Bit)
Selection
Order
1.
2.
3.
4.
1-0-3-2*
Byte 1
(MMMMMMMM)
Byte 0
(MMMMMMMM)
Byte 3
(SEEEEEEE)
Byte 2
(EMMMMMMM)
0-1-2-3
Byte 0
(MMMMMMMM)
Byte 1
(MMMMMMMM)
Byte 2
(EMMMMMMM)
Byte 3
(SEEEEEEE)
2-3-0-1
Byte 2
(EMMMMMMM)
Byte 3
(SEEEEEEE)
Byte 0
(MMMMMMMM)
Byte 1
(MMMMMMMM)
3-2-1-0
Byte 3
(SEEEEEEE)
Byte 2
(EMMMMMMM)
Byte 1
(MMMMMMMM)
Byte 0
(MMMMMMMM)
* Factory default, S = Sign, E = Exponent, M = Mantissa
4.4.3 String
Selection
Order
1.
2.
…
n-1
n
1-0-3-2*
3-2-1-0
Byte 1
Byte 0
(LSB)
…
Byte n-1
(MSB)
Byte n-2
0-1-2-3
2-3-0-1
Byte 0
(LSB)
Byte 1
…
Byte n-2
Byte n-1
(MSB)
* Factory default, MSB = most significant byte, LSB = least significant byte

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4.5 Device variables
The device variables are used to transmit process values to and from the device.
Device
variable
Name
Info
Example
AI1 ... AI16
Analog Input
Process value that is read from the device
Read measured value
DI1 … DI8
Digital Input
Process value that is read from the device
Read limit switch state
AO1 … AO4
Analog Output
Process value that is written to the device
PID controlled variable
DO1 … DO8
Digital Output
Process value that is written to the device
Start cleaning signal
4.5.1 AI –Analog input (PLCDevice)
Each AI device variable consists of the following elements:
Register-Offset
Data type
Element
Description
0-1
Float
Value
Measurement value
2
Unsigned8
Status
Validity of value, see 0
3
Unsigned8
Unitcode
Unit of value, see section 7.3
The mapping between AI device variable and measurement value must be configured in the menu.
Path: Menu/Setup/Outputs/Modbus/AI 1 (Analog Input) … AI 16 (Analog Input)
Function
Options
Info
Source of
data
Options
None
Any data source
Factory setting
None
The data sources presented for selection depend on
your device version. You can choose from all the
sensors connected to the inputs, controllers as well as
mathematic functions and current inputs.
For more information and an overview about the
available options see main operation manual.
Measured
value
Options
None
Depends on data source
Factory setting
None
The measured value that you can choose depends on
the option selected under "Source of data".
For more information and an overview about the
available options see main operation manual.

SD01189C/07/EN/04.17
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18 © Copyright Dec. 2016
4.5.2 Example
Step
Action
Result
1
Enter menu
/Setup/Outputs/Modbus
2
Select an AI device variable, e.g. AI1
3
Select data source and measurement value
After these steps the value, status and unit code can be read from Modbus holding register 0. The mapping
of DI device variables is done in the manner described for AI device variables.

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19
4.5.3 DI –Digital input (PLCDevice)
Each DI device variable consists of the following elements:
Register-Offset
Data type
Element
Description
0
Unsigned8
Value
0 (false) or 1 (true)
1
Unsigned8
Status
Validity of value, see 0
Path: Menu/Setup/Outputs/Modbus/DI 1 (Digital Input) … DI 8 (Digital Input)
Function
Options
Info
Function
Options
Off
Source value
Diagnostics
Factory setting
Off
If Function = Source value:
Source of
data
Options
None
Limitswitches
Alarmrelay
Relay
Binaryinputs
Factory setting
None
The data sources presented for selection depend on your
device configuration. For more information see operating
manual.
If Function = Diagnostics:
Operating
mode
Options
as assigned
Namur M
Namur S
Namur C
Namur F
Factory setting
as assigned
For more information see operating manual.
Hold
behavior
Options
Freeze
None
Factory setting
None
For more information see operating manual.

SD01189C/07/EN/04.17
Endress+Hauser
20 © Copyright Dec. 2016
4.5.4 AO –Analog output (PLCDevice)
Each AO device variable consists of the following elements:
Register-Offset
Data type
Element
Description
0-1
Float
Value
Measurement value
2
Unsigned8
Status
Validity of value, see 0
3
Unsigned8
Unitcode
Unit of value, see section 7.3
Path: The device variables are selected in the menu of the function that uses the actuating value.
Liquiline CM44x, Liquiline System CA80xx, Liquistation CSFxx:
Menu/Setup/Additional functions/Limit switches/…/Source of data
Menu/Setup/Additional functions/Controllers/…/Controlled variable/Source of data
Menu/Setup/General settings/Logbooks/Data logbooks/Source of data
Menu/Display/User definable screens/…/Source of data
For more information see main operation manual. Basically the same connections for device variables are
equivalent to the connections available for analog input and outputs:
A device variable AO corresponds to a current input and typically has the same connection possibilities.
4.5.5 DO –Digital output (PLCDevice)
Each DO device variable consists of the following elements:
Register-Offset
Data type
Element
Description
0
Unsigned8
Value
0 (false) or 1 (true)
1
Unsigned8
Status
Validity of value, see 0
The mapping of DO device variables is done in the manner described for AO device variables.
Path: The device variables are selected in the menu of the function that uses the actuating value.
Liquiline CM44x, Liquiline System CA80xx, Liquistation CSFxx:
Menu/Setup/Additional functions/Controllers/…/Controller Enable
Menu/Setup/Additional functions/Cleaning/…/Start signal
Menu/Setup/General settings/Hold settings/External hold
Menu/Setup/General settings/Logbooks/Data logbooks/Source of data
Menu/Setup/Inputs/Sensor/Extended setup/External hold/Source
Menu/Display/User definable screens/…/Source of data
Liquistation CSFxx only:
Menu/Sample-Program/Programsetup/Advanced/Startcondition
Menu/Sample-Program/Programsetup/Advanced/Startsignal
Menu/Sample-Program/Programsetup/Advanced/Stopcondition
Menu/Sample-Program/Programsetup/Advanced/Stopsignal
Menu/…/Advanced/Subprogramsetup/Samplemode
Menu/…/Advanced/Subprogramsetup/Samplesignal
Menu/…/Advanced/Subprogramsetup/Bottle change
Menu/…/Advanced/Subprogramsetup/Change signal