Fuji Electric PXH Operating Manual

Instruction Manual

DIGITAL CONTROLLER COMMUNICATION FUNCTIONS (MODBUS)

TYPE: PXH

INP-TN514207-E

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Note: Visual Basic® is the registered trade mark of Microsoft Corporation.

Note: MODBUS® is the registered trade mark of Gould Modicon.

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The contents of this document may be changed in the future without prior notice. We paid the utmost care for the accuracy of the contents. However, we are not liable for direct and indirect damages resulting from incorrect descriptions, omission of information, and use of information in this document.

Notice

CONTENTS....................................................................................................................... i

1. COMMUNICATION FUNCTIONS ......................................................................................1

1.1 Outline..........................................................................................................................1

2. SPECIFICATIONS.................................................................................................................2

2.1 Communication Specifications ....................................................................................2

3. CONNECTION ......................................................................................................................3

3.1 Communication Terminal Allocation...........................................................................3

3.2 Wiring ..........................................................................................................................4

4. SETTING OF COMMUNICATION CONDITION...............................................................6

4.1 Setting items.................................................................................................................6

4.2 Setting Operation Method............................................................................................7

5. MODBUS COMMUNICATION PROTOCOL......................................................................8

5.1 Outline..........................................................................................................................8

5.2 Composition of Message..............................................................................................9

5.3 Response of Slave Station..........................................................................................11

5.4 Function Code ............................................................................................................12

5.5 Calculation of Error Check Code (CRC-16)..............................................................13

5.6 Transmission Control Procedure................................................................................14

5.7 FIX Processing (Cautions in data write) ....................................................................16

6. DETAILS OF MESSAGE....................................................................................................17

6.1 Read-out of Word Data ［Function code: 03H］......................................................17

6.2 Read-out of Read-out Only Word Data [Function code: 04H]....................................19

6.3 Write-in of Word Data (1 word) [Function code: 06H]...............................................21

6.4 Write-in of Continuous Word Data [Function code: 10H] ..........................................22

7. ADDRESS MAP AND DATA FORMAT.............................................................................24

7.1 Data Format................................................................................................................24

7.2 Communication Address Map ....................................................................................28

8. SAMPLE PROGRAM .........................................................................................................37

9. TROUBLESHOOTING .......................................................................................................43

INP-TN514207-E

1. COMMUNICATION FUNCTIONS

1.1 Outline

▪ Via RS-485 interface and PC loader interface, PXH provides communication functions of transmit-

ting and receiving data to and from host computer, programmable controller, graphic panel, etc.

▪ The communication system consists of master station and slave stations. For RS-485 communica-

tion, up to 31 slave stations (PXHs) can be connected per master station.

Note that, because the master station can communicate with only one slave station at a time, a party

to communicate with must be specified by the "Station No." set at each slave station. For loader communication, one slave station (PXH) can be connected per master station.

▪ In order that the master station and slave station can communicate, the format of the trans-

mit/receive data must coincide. For the PXH, the format of the communication data is determined by the MODBUS protocol.

▪ Please use an RS-232C ⇔ RS-485 converter in case of designating a personal computer or other

devices which have an RS-232C interface as a master station. ［RS-232C ⇔ RS-485 converter］ (recommended article)

Type: RC-77 (isolated type)/ RA SYSTEMS make http://www.ras.co.jp Type: K3SC-10 (isolated type)/ OMRON make http://www.omron.co.jp

RS-232C communication with PC is available upon connecting Type: ZZPPXH1*TK4H4563 to PC loader interface where PXH is provided in standard.

Programmable controller

RS-485

RS-232C

RS-485

Personal computer

RS-232C D-sub9 pin

RS-232C

RS-485 communication converter

Caution:

When using the RS-232C ⇔ RS-485 converter, pay attention to cable connection between the con-

verter and master station. If the cable is not connected correctly, the master station and slave station

cannot communicate. In addition, be careful about communication settings such as baud rate and parity set for the converter.

PC loader interface

INP-TN514207-E

2. SPECIFICATIONS

2.1 Communication Specifications

■ RS-485

Item Specification

Electrical specification Based on EIA RS-485

Transmission method 2-wire, half duplex

Synchronous system Start-stop synchronous system

Connection format 1 : N

Number connectable units Up to 31 units

Transmission distance 500m max. (total extension distance)

Transmission speed 9600bps, 19200bps, 38400bps

Data format Data length 8 bits

Stop bit 1 bit

Parity none, even, odd (selectable)

Transmission code HEX value (MODBUS RTU mode)

Error detection CRC-16

Isolation

■ PC loader interface

Functional isolation between transmission circuit

and others (withstand voltage : 500V AC)

Item Specification

Electrical specification EIA RS232C

Transmission method 3-wire, half duplex, bit-sereal

Synchronous system Start-stop synchronous system

Connection format 1 : 1

Transmission speed 9600bps, 19200bps, 38400bps

Data format Data length 8 bits

Stop bit 1 bit

Parity none, even, odd (selectable)

Transmission code HEX value (MODBUS RTU mode)

Error detection CRC-16

Isolation Non-isolated from internal circuit

INP-TN514207-E

3. CONNECTION

WARNING

For avoiding electric shock and malfunctions, do not turn on the power supply until all wiring is completed.

3.1 Communication Terminal Allocation

■ PXH9 (RS-485)

Terminal number (14) (15) (16)

Signal name

■ PXH9 (PC loader interface)

PC loader interface

RS485

–

Φ2.5, 3-pole miniature jack

INP-TN514207-E

3.2 Wiring

■ RS-485

▪ Use twisted pair cables with shield. Recommended: KPEV-SB (Furukawa Electric make)

▪ The total extension length of the cable is up to 500 m. A master station and up to 31 units of the

PXH can be connected per line.

▪ Both ends of the cable should be terminated with terminating resistors 100Ω (1/2W or more).

▪ If the PXH is to be installed where the level of noise applied to the PXH may exceed 1000 V, it is

recommended to install a noise filter in the master station side as below. Recommended noise filter: ZRAC2203-11 (TDK make)

▪ If problematic in EMC at communication, loading the communication cable with ferrite can lower

the noise level.

Recommended ferrite core: ZCAT series (TDK make) MSFC series (Morimiya Electric make)

Master station

(PC, etc.)

RS-232C⇔RS-485

Master station side

Twisted pair cable with shield

RS-485 interface

RS-485 side of the RS-232C RS-485 converter

Terminating resistor 100Ω (1/2W)

Noise filter PXH

Transmission

cable

Slave (PXH)

▪ SG connection is not mandatory, but is

effective for remedying communication

errors attributable to noises.

Terminating resistor 100Ω (1/2W)

INP-TN514207-E

■ PC loader communication

▪ Use an optional PC loader communication cable (RS-232C).

PC loader communication cable

Master station side

(RS232C) ZZPPXH1 TK4H4563

PC or the like

RS232C

D-Sub 9 pins

Bottom of PXH

INP-TN514207-E

4. SETTING OF COMMUNICATION CONDITION

In order that the master station and instrument (PXH) can correctly communicate, following settings are required.

▪ All communication condition settings of the master station and those of instruments (PXH) are indentical.

▪ For RS-485 communication, different "station numbers (STN4)" are assigned to all PXHs which are con-

nected to a common line. (Any "Station No." is not shared by more than one instrument.)

▪ For PC loader communication, the station No. is fixed at "1".

Both for PC loader communication and RS-485 communication, same station No. "1" may be assigned.

4.1 Setting items

The parameters to be set are shown in the following table. Set them by operating the front panel

keys.

■ RS-485

CH B COM

Parameter

symbol

SPD4

――― Data length 8 bits Fixed (can not be changed)

――― Stop bit 1 bit Fixed (can not be changed)

BIT4 Parity setting odd

STN4 Station No. 1

■ PC loader communication

CH B COM

Parameter

symbol

SPD2

――― Data length 8 bits Fixed (can not be changed)

――― Stop bit 1 bit Fixed (can not be changed)

BIT2 Parity setting odd

――― Station No. 1 Fixed (can not be changed)

Item

Transmission

speed

Item

Transmission

speed

Value at delivery

38400bps

Value at delivery

38400bps

Setting range Remarks

96 : 9600bps 192 : 19200bps 384 : 38400bps

8n : none parity

8o : odd parity

8E : even parity

0 to 255

(0: communication function stop)

Setting range Remarks

96 : 9600bps 192 : 19200bps 384 : 38400bps

8n : none parity

8o : odd parity

8E : even parity

Set the same communication condition to the master station and all slave stations.

Set a different number to each station.

Set the same conditions as the master station.

INP-TN514207-E

4.2 Setting Operation Method

The following example shows how to set the communication conditions.

Example: For RS-485, set BIT4 parity at even and STN4 at 18.

Key

operation

SEL

∨

SEL

>∧∨

SEL

∨

SEL

Indication Description

200

LP01SV

200

PS1

0000

b COM

b. STN4 02 1

b. STN4 02 00001

b. STN4 02 00018

b. STN4 02 18

b. BIT4 04 8o

Operation status (PV/SV indication) or (PV/MV indication)

Press the SEL key to display PS1.

Press the ∨ key repeatedly until b.COM channel appears. (If past over, press the ∧ key to return.)

Press the SEL key to display STN4 parameter.

Press the SEL key. The numeric value on the lower indicator blinks and the setting mode is selected.

Press the >, ∧, or ∨ key to change the numeric value to 18.

Press the SEL key again. The numeric value stops blinking and the setting is registered.

Press the ∨ key to display the BIT4 parameter.

Press the SEL key. The numeric value on the lower indicator blinks and the setting mode is selected.

∧∨

SEL

DISP

b. BIT4 04 8E

b COM

LP01SV

200

Press the ∧ or ∨ key until the numeric value changes to 8E (even parity).

Press the SEL key again. The numeric value stops blinking and the setting is registered.

Press the DISP key to resume b.COM channel indication.

Press the DISP key to resume the operation status (PV/SV indication).

* Be sure to turn off and on power so that the communication condition settings will affect the control.

INP-TN514207-E

5. MODBUS COMMUNICATION PROTOCOL

5.1 Outline

The communication system by the MODBUS protocol is that the communication always starts from the master station and a slave station responds to the received message.

Transmission procedures is 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 command 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 to slave

Slave to master

b) In case when the station No. in the received command message mismatches with the own

slave station No.

Master to slave

Slave to master

The master station can individually communicate with any one of slave stations connected on the same line upon setting the station No. in the command message.

Command message

Response message

(Not respond)

Data on

the line

Data on

the line

INP-TN514207-E

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 the following order.

Station No. (1 byte)

Function code (1 byte)

Data (2 to 69 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. For RS-485 communication, the command

is processed only by the slave station whose station No. matches with the No. set in the parameter "STN4".

For details of setting the parameter "STN4", refer to chapter 4.

For PC loader communication, the station No. is fixed at "1".

(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

Data are the data required for executing function codes. The composition of data varies with function codes. For details, refer to chapter 6.

A register number is assigned to each data in the indicating controller. For using the data by

communication, designate the register number.

Note that the register number transmitted on message is expressed as its relative address.

The relative address is calculated by the following expression.

Relateve address



The lower 4 digits of the

＝

 



– 1

 

For example, when the resister number designated by a function code is 40003,

Relative address = (lower 4 digits of 40003) – 1

= 0002 is used on the message.

INP-TN514207-E

(4) Error check code

This is the code to detect message errors (change in bit) in the signal transmission.

On the MODBUS protocol (RTU mode), CRC-16 (Cycric Redundancy Check) is applied.

For CRC calculation method, refer to section 5.5.

INP-TN514207-E

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 corre-

sponds 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 contents of a command message have an abnormality (for example, non-actual function code is

designated) other than transmission error, the slave station does not execute that command but creates and sends back a response message at error detection.

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.

Function code + 80H

Error check（CRC-16）

Station No.

Error code

Error code Contents Description

01H Illegal function code Non-actual function code is designated.

02H Illegal data address A relative address of resister number to which the

03H Illegal data value Because the designation of number is too much,

(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 speci-

▪ A 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

▪ Station No. of a slave station is set as 0.

▪ A write-in command is sent while executing FIX.

Fig. 5-2 Response message at error detection

Table 5-1 Error Code

Check for the function code.

designated function code can not be used.

the area where resister numbers do not exist is designated.

fied to the slave station.

corresponding to 24 bits. (Refer to section 5.6 Transmission Control Procedure.)

INP-TN514207-E

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 Resister No.

No. Function Object No. Contents

03H

04H

06H Write-in Holding register 4xxxx Read-out/write-in word data

10H

Read-out (continuously)

Write-in (continuously)

Holding register 4xxxx Read-out/write-in word data

Input register 3xxxx Read-out word data

Holding register 4xxxx Read-out/write-in word data

Table 5-3 Function code and message length

Function

code

03H Read-out of word data 32 words 8 8 7 69 04H

06H Write-in of word data 1 word 8 8 8 8

10H

*1) For PXH, all data is designated by 2 words.

Read-out of word data

(read-out only)

Write-in of continuous word data

(write-in of word data) is used, only 1 lower word can be written in, and only 1 upper word

If 06

cannot.

Contents

Number of

designatable

data

15 words 8 8 7 35

32 words 11 73 8 8

[Unit:byte]

Command message Response message

Minimum Maximum Minimum Maximum

INP-TN514207-E

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Fuji Electric PXH Operating Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

CONTENTS

Function code Resister No.