Fuji Electric ZKM Operating Manual
Service Manual
ZIRCONIA OXYGEN
ANALYZER CONVERTER
transmission specification
(MODBUS)
TYPE: ZKM
INZ-TN5A0506-E
CONTENTS
1. COMMUNICATION FUNCTION.................................................................................................. 1
1.1 Outline.....................................................................................................................................................1
2. SPECIFICATIONS .......................................................................................................................... 2
2.1 Communication specifications................................................................................................................2
3. CONNECTION................................................................................................................................ 3
3.1 Setting of jumper pin ..............................................................................................................................3
3.2 Terminal allocation (TM2)......................................................................................................................3
3.3 Connection..............................................................................................................................................4
4. SETTING OF COMMUNICATION CONDITION........................................................................ 6
4.1 Setting item.............................................................................................................................................6
4.2 Setting operation.....................................................................................................................................6
5. MODBUS COMMUNICATION PROTOCOL............................................................................... 7
5.1 Outline.....................................................................................................................................................7
5.2 Composition of Message.........................................................................................................................8
5.3 Response of Slave Station.......................................................................................................................9
5.4 Function Code.......................................................................................................................................10
5.5 Calculation of Error Check Code (CRC-16)......................................................................................... 11
5.6 Transmission Control Procedure...........................................................................................................13
6. DETAILS OF MESSAGE ............................................................................................................. 15
6.1 Word data readout [Function code: 03H]...............................................................................................15
6.2 Reading Read-Only Word Data [Function Code: 04H] .........................................................................16
6.3 Writing Word Data (unit of 1word) [function code: 06H] .....................................................................17
6.4 Writing Continuous Word Data [Function code: 10H] ..........................................................................18
7. ADDRESS MAP AND DATA FORMAT .................................................................................... 19
7.1 Data format ...........................................................................................................................................19
7.1.1 Transmission data format............................................................................................................19
7.1.2 Handling of decimal point position and measurement unit ........................................................19
7.1.3 Handling at measurement data over-range..................................................................................19
7.2 Address map..........................................................................................................................................20
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1. COMMUNICATION FUNCTION
1.1 Outline
• This instrument provides a communication function through RS232-C and RS-485 which allows data
transmit to or receive from the host computer and other devices.
• The communication system is composed of a master and slave relationship.
Up to 31 of slave station (present instrument) can be connected per master station (host computer,
programmable controller, graphic display panel, etc.) through RS485 interface.
One slave station (this instrument) can be connected to one master station.
• Because the master station can communicate with only one slave station at a time, the destination can be
identified by the “Station No.” set for each slave station.
• In order that the master station and slave station can communicate, the format of the transmit/receive data
must coincide. For the PXR, the format of the communication data is determined by the MODBUS
protocol.
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2. SPECIFICATIONS
2.1 Communication specifications
(a) RS-232C Interface
Item SPECIFICATIONS
Electrical specification Communication standard: RS-232C
Communication method 2-wire, semi-duplicate
Synchronizing method Start-stop synchronous system
Connection format 1:1
Number connectable units 1 unit
Baud rate 38400 bps
Data Format
Transmission code HEX value (MODBUS RTU mode)
Error detection CRC-16
Isolation Not isolated against communication part and other parts.
(b) RS-485 interface
Item SPECIFICATIONS
Electrical specification Based on EIA RS-485
Communication method 2-wire, semi-duplicate
Synchronizing method Start-stop synchronous system
Connection format 1:N
Number connectable units 31 units
Communication distance Maximum 500m (total extansion)
Baud rate 38400 bps
Data Format
Transmission code HEX value (MODBUS RTU mode)
Error detection CRC-16
Isolation Isolation from internal circuit
Data length 8 bits
Stop bit 1 bits
Parity None
X flow control None
Data length 8 bits
Stop bit 1 bits
Parity None
X flow control None
Functional isolation between signal line and ground
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3. CONNECTION
WARNING
Do not turn on the power supply until all wiring have been completed to avoid electric shock
and malfunctions.
3.1 Setting of jumper pin
Depending on the kind of communication, switch the jumper pin.
Communication JP1 JP2 JP5
RS 232C
RS 485
3 - 5
4 - 6
1 - 3
2 - 4
3 - 5
4 - 6
1 - 3
2 - 4
2 - 3
1 - 2
3.2 Terminal allocation (TM2)
(a) RS-232C Interface
Terminal number Signal name Pin connection
1 Transmission data (TXD)
2 Receive Data (RXD)
3 Signal ground
(b) RS-485 Interface
Terminal number Signal name Pin connection
1 RTxD+
2 RTxD-
3 Singnal ground
123
123
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3.3 Connection
(a) RS-232C Interface
Master
RXD
Twis te d pa ir cable
with s hie ld
Slave (ZKM)
TXD
(b) RS-485 interface
• Please use a shielded twist pair cable.
(Recommended cable: KPEV-SB (made by The Furukawa Electric Co., Ltd.))
• The total extension length of the cable is up to 500 m. One master and up to thirty-one micro
controllers (slaves) can be connected per circuit.
• Both ends of the cable should be terminate with terminating resistors 100Ω (1/2W or more).
• Ground the shielded cable once towards the master side.
TXD
SG SG
FG
RXD
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• SG does not have to be connected, but it can be used as an effective countermeasure against
communication errors due to noise.
• When using the micro controller in an area where the imposed noise level is expected to exceed 500V,
we recommend using a noise filter on the master side as seen in the figure below.
[Noise filter] (Recommended): ZRAC2203-11 (made by TDK Corporation)
Master
N ois e lter
RS-485
Ma in unit
• If there are problems with EMC during communication, the noise level can be reduced by using a
communication cable with a ferrite core.
Ferrite core (recommended): ZCAT series (made by TDK Corporation)
MSFC series (made by Morimiya Electric Co., Ltd.)
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4. SETTING OF COMMUNICATION CONDITION
In order that the master station and instrument (this instrument) can correctly communicate, following settings
are required.
• All communication condition settings of the master station are the same as those of instruments (this
instrument).
• All instruments (this instrument) connected on a line are set to “Station No.” which are different from each
other. (Any “Station No.” is not shared by more than one instrument.)
4.1 Setting item
The parameters to be set are shown in the following table.
Set them by operating keys on the screen.
Item
Baud rate 38400 bps Fixed (can not be changed)
Data length 8 bits Fixed (can not be changed)
Stop bit 1 bits Fixed (can not be changed)
Parity setting None Fixed (can not be changed)
Station No. 1
Factory shipment
default
Settable range Remarks
0 to 31
(0: Communication function stops )
Set the same communication
condition to the master station
and all slave stations.
Set a different value to each
station.
4.2 Setting operation
Set the station No. on the parameter screen. (Refer to the instruction manual)
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5. MODBUS COMMUNICATION PROTOCOL
5.1 Outline
The communication system by the MODBUS protocol is that the communication is always started from the
master station and a slave station responds to the received message.
Transmission procedures are as shown below.
1) The master station sends a command message to a slave station.
2) The slave station checks that the station No. in the received message matches with the own station No.
or not.
3) If matched, the slave station executes the command and sends back the response message.
4) If mismatched, the slave station leaves the message and wait for the next command message.
(a) In case when the station No. in the received command message matches with the own slave station No.
Master Slave
Master Slave
(b) In case when the station No. in the received command message matches with the own slave station No.
Comma nd mess a ge
R esponse message
Data on lin
Master Slave
Master Slave
The master is connected to the same line by specifying the station No. in the command message. For multiple
slaves, it is possible to communicate individually.
Comma nd mess a ge
(No response)
Data on lin
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5.2 Composition of Message
Command message and response message consist of 4 fields; Station No., Function code, Data and Error check
code. And these are sent in this order.
Station No. (1 Byte)
Function Code (1 Byte)
Data Part (2 to 133 Bytes)
Error check code (CRC-16) (2 Bytes)
Fig. 5-1 Composition of message
In the following, each field is explained.
(1) Station No.
Station No. is the number specifying a slave station. Only a slave station that corresponds to a value to
which “Station No.” is set on the analyzer maintenance mode display executes a command.
(2) Function code
This is a code to designate the function executed at a slave station.
For details, refer to section 5.4.
(3) Data part
Data are the data required for executing function codes. The composition of the data part is different
depending on the function code. For details, refer to chapter 6.
A register number is assigned to each data in the analyzer. For reading/writing the data by communication,
designate the register number.
=
Relative address
Coil number or register number
For example, the register number specified by certain function code = in case of 4003
Relative address = (Lower 4 digits of 40003) – 1
= 0002
The message above will be used.
of last 4 digits.
– 1
(4) Error check code
This is the code to detect message errors (change in bit) in the signal transmission.
MODBUS protocol (RTU mode) uses CRC16 (Cyclic Redundancy Check).
For CRC calculation method, refer to section 5.5.
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5.3 Response of Slave Station
(1) Response for normal command
To a relevant message, the slave station creates and sends back a response message which corresponds to
the command message. The composition of message in this case is the same as in Section 5.2.
Contents of the data field depend on the function code. For details, refer to chapter 6.
(2) Response for abnormal command
If there are problems (such as specification of a nonexistent function code) with the contents of the
command message other than transmission error, the slave creates and replies with an error response
message without following the command.
The composition of response message at error detection is as shown in Fig. 5-2 the value used for function
code field is function code of command message plus 80
Table 5-1 gives error codes.
Station No. (1 byte)
.
H
Function code + 80H (1 byte)
Error code (1 byte)
Error check code (CRC-16) (2 bytes)
Fig. 5-2 Response message at error detection
Table 5-1 Error Code
Error code Contents Explanation
01H Illegal function code Non-actual function code is designated.
Check for the function code.
02H Faulty address for coil or register A relative address of a coil number or resister
number to which the designated function
code can not be used.
03H Illegal data value Because the designation of number is too
much, the area where resister numbers do not
exist is designated.
(3) No response
Under any of the following items, the slave station takes no action of the command message and sends
back no response.
• A station number transmitted in the command message differs from the station number specified to
the slave station.
• An error check code is not matched, or a transmission error (parity error, etc.) is detected.
• The time interval between the composition data of the message becomes longer than the time
corresponding to 24 bits. (Refer to Section 5.6 Transmission Control Procedure)
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5.4 Function Code
According to MODBUS protocol, register numbers are assigned by function codes. Each function code acts on
specific register number.
This correspondence is shown in Table 5-2, and the message length by function is shown in Table 5-3.
Table 5-2 Correspondence between function codes and objective address
Function Code Register No.
No. Function Remedy No. Contents
03H reading (continuance) Holding register 4xxxx Reading/writing Word data
04H reading (continuance) Input register 3xxxx Reading Word data
06H Writing Holding register 4xxxx Reading/writing Word data
10H Writing (continuance) Holding register 4xxxx Reading/writing Word data
Table 5-3 Function code and message length
[UNIT: byte]
Function Code Contents
03H Read word data 64 words
04H Read word (Read only) 64 words
06H Write word data 1 word 8 8 8 8
10H Write continuous word data 64 words
Designated
data
Command
message
Mini. Max. Mini. Max.
887 133
887 133
11 137 8 8
Response
message
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