IDEC FC4A Series Instruction Manual

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This document describes communication commands for the MicroSmart micro programmable controller.

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Table of Contents

Communication Command List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Communication Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Message Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Request Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Receive Timeout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Reply Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Write User Program in ASCII Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Write User Program in Binary Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Read User Program in ASCII Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Read User Program in Binary Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Write N Bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Read N Bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Write 1 Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Read 1 Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Read Error Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Clear Operand Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Enable/Disable User Program Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Read PLC Operating Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Read Scan Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Read PLC System Program Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Read Timer Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Read Counter Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Read Timer Preset Value Change Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Read Counter Preset Value Change Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Read Timeout Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Read Countout Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Confirm Changed Timer/Counter Preset Values . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

NG Code and Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Operand Allocation Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

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Communication Command List

All communication commands available for the

MicroSmart, OpenNet Controller (ONC)

,

MICRO

3

, and
rized in the table below. Some of the commands are the same as for different PLCs, with increased operands and operand
number ranges.

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are summa-

Command Name MicroSmart ONC MICRO
Write User Program in ASCII Format
Write User Program in Binary Format
Read User Program in ASCII Format
Read User Program in Binary Format
Write N Bytes

3

C MICRO

XXXX
XXXX
XXXX
XXXX
XXXX

3

Read N Bytes (Note) XXXX
Write 1 Bit
Read 1 Bit
Read High-speed Counter Preset and Current Values
Read Error Code
Clear Operand Data
Enable/Disable User Program Protection
Read PLC Operating Status
Read Scan Time
Read PLC System Program Version
Read User Communication Transmit/Receive Buffer

XXXX
XXXX

XXX
XXXX
XXXX
XXXX
XXXX
XXXX
XXXX

XX

Clear and Start User Communication Data Monitor
Read User Communication Status

XX

Read Communication Mode
Select Word Operands for Monitor
Monitor Selected Word Operands
Read Timer Information
Read Counter Information
Read Timer Preset Value Change Status
Read Counter Preset Value Change Status

XX
XX
XX
XX

Read FUN Area Settings
Read Random Words
Read Timeout Status
Read Countout Status
Confirm Changed Timer/Counter Preset Values

X

Note: When timer/counter preset or current values are read out from the MicroSmart using the read N bytes command, the

result is different from that read from the MICRO

3

because the MicroSmart has different timer and counter internal codes to
enable 16-bit timers and counters. The MicroSmart has new commands for timers and counters; Read Timeout Status and
Read Countout Status.

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Communication Procedure

The computer and the
which consist of request messages and reply messages. The request message is sent from the computer to write data to,
read or clear data from the
from the computer.

Communication is always initiated by the computer by sending a request message to the
reply message to the computer. The

can initiate communication using the user communication function.

Smart

MicroSmart

Computer

CPU module communicate data by sending and receiving communication messages,

MicroSmart

MicroSmart

. The reply message is sent from the

cannot initiate communication in the computer link system. The

Request Message

Reply Message

MicroSmart

in response to the request message

MicroSmart

, which then returns a

MicroSmart

CPU Module

Micro-

Message Format

Communi­cation
Message

(1) (2) (3) (4) (5)

BCC (Block Check Character) Calculation Range

(1)

(2)

(3)

(4)

(5)

Communication
control
character
(1 byte)

Communication
device number
(2 bytes)

Data
(variable length)

BCC
(2 bytes)

Terminator
(1 byte)

Message start
character

Device number to
send request to

Device number to
send reply from

Communication
command,
data type, etc.

Block check
character

Message
end code

ENQ (05h) Enquiry Request message
ACK (06h)

NAK (15h)
00 (0)

through
1F (31)

FF (255)
00 (0)

through
1F (31)

Depends on each command.
See “Request Messages” on page 3.
See “Reply Messages” on page 5.

Exclusive OR (XOR) of the BCC calculation range.

CR (0Dh) Default

Acknowledge
Negative acknowledge

Designates a PLC device number to which the com­puter sends a request message in the 1:N communi­cation computer link system.

Used in the 1:1 communication computer link system.
PLC of any device number receives request message.

Indicates the device number of the PLC which returns
the reply message.

Reply message

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Request Messages

ONC

Like the

MICRO

or

structures.

Request Message 1

Request message 1 is a command message to be sent from the computer to the PLC, containing a command. The data type
code included in the request message determines the function. The data structure of request message 1 is shown below.

Request
Message 1

(1)

(2)

(3)

(4)

Continuation
(1 byte)

Command
(1 byte)

Data type
(1 byte)

Data
(variable length)

3

, request messages are available in request message 1 and request message 2 with different data

ENQ

Device (2) (4)(3)05h (1) BCC

0 (30h) Discontinued (no message follows)
1 (31h) Continued (another message follows)

W (57h) Write data to PLC

R (52h) Read data from PLC
C (43h) Clear data from PLC

X (58h)
Y (59h) Output

M (4Dh) Internal relay

R (52h) Shift register D (44h) Data register
T (54h)

C (43h)
E (45h) Error code (read/clear)

I (49h) Link formatting sequence (clear)
K (4Bh) Scan time (read)
N (4Eh) PLC system program version (read)
P (50h) User program in ASCII format (read/write)

Q (51h) Changed timer/counter preset values (write)
S (53h) PLC operating status (read)
V (56h) User program protection

W (57h) Calendar/clock (read/write)

Z (5Ah) System reset (clear)
_ (5Fh) Timer information (read)
` (60h) Counter information (read)

a (61h) Timer preset value change status (read)
b (62h) Counter preset value change status (read)
d (64h) Timer timeout status (read)
e (65h) Counter countout status (read)
p (70h) User program in binary format (read/write)

Data (depends on command and data type)

Input

Timer
(preset value)

Counter
(preset value)

N-byte
designation

t (74h)

c (63h)

x (78h) Input
y (79h) Output

m (6Dh) Internal relay

r (72h) Shift register

Timer
(current value)

Counter
(current value)

Termi-

nator

N-byte
designation

1-bit
designation

(1)

“Continued” is used in request message 1 for writing the user program to inform the PLC that another request message
will be sent successively. In all other request messages, “discontinued” is used. When “continued” is specified, the
computer sends a request message, receives a reply message, and sends another request message.

(2)

The command code is available in three types; write data, read data, and clear data.

(3)

The data type code selects an operand or function. Upper- and lower-case characters have different functions.
The data specifies the operand number, the quantity of bytes of the data for reading or writing, etc. depending on the

(4)

command and data type.

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Request Message 2

Request message 2 is a command message used for writing and reading user programs. The data structure of request mes­sage 2 is shown below:

Request
Message 2

(1)

(2)

(1)

“Discontinued” is used for both writing and reading user programs to inform the PLC that no request message will be
sent successively.

(2)

The data length is variable for writing user programs and is 1-byte long (“R”) for reading user programs.

ENQ

Device (2)05h (1) BCC

Continuation
(1 byte)

Data
(variable length)

Data
(1 byte)

0 (30h) Discontinued (no message follows)

User program (write user program)

R (52h) Read user program

Termi-

nator

Receive Timeout

When a request message contains an interval of 500 msec or more between one­byte character data and the next one-byte character data, the PLC understands that
the communication is canceled and does not return a reply message.

When the interval is 500 msec or more, extend the receive timeout value using

WindLDR

. The receive timeout can be selected between 10 and 2540 msec in 10­msec increments. To enable the optional communication mode, turn on the mode
selection input designated on the Communication Parameters page in

T o access the Communication P arameters page from the

WindLDR

WindLDR

.

menu bar, select Configure > Function Area Settings .
In the Function Area Setting dialog box, click the Communication tab, and select Maintenance Protocol in the Port 1 or
2 pull-down list.

Click the Configure button. The Communication Parameters dialog box appears. Change settings, if required.

Baud Rate (bps) 1200, 2400, 4800, 9600, 19200
Data Bits 7 or 8
Parity None, Odd, Even
Stop Bits 1 or 2

10 to 2540 (10-msec increments)

Receive Timeout (ms)

Device Number 0 to 31
Mode Selection Input Any input number

(Receive timeout is disabled when 2550
is selected.)

Data Data

≤ 500 msec

Note: Only when the mode selection input is turned on, the selected communication parameters are enabled.
Otherwise, default communication parameters take effect; 9600 bps, 7 data bits, even parity, 1 stop bit,
receive timeout 500 msec.

For details, see the MicroSmart User’s Manual EM342, page 25-2.

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Reply Messages

Reply messages are available in ACK reply message and NAK reply message with different data structures.

ACK Reply Message

The ACK reply message is a reply or response to the request message and is sent from the PLC to the computer when com­munication is completed normally.

ACK
Reply
Message

(1)

(2)

ACK

Device (2)06h (1) BCC

0 (30h) OK: Discontinued All communication is completed normally (end of processing).

Communication in reply to request is completed normally and
another reply message follows when reading a user program.

Communication device number, command, data type, data, or con­tinuation code is not within the range supported by the PLC or
does not match its status. When this error occurs, communication
is halted without regard to the continuation code.

The data length depends on the request
command (variable length).

Command
(1 byte)

1 (31h) OK: Continued

2 (32h) NG: Error

OK
reply

When request command is W or C No data exists. (0 byte)
When request command is R

NG code (2 bytes)

Data
(variable
length)

0 (30h)
to
9 (39h)

or

A (41h)
to
F (46h)

NG
reply

NG

Code

Program size error Improper write/read program size

01

Protect error Protected against write/read in the PLC

02

RUN error Writing user program is attempted while the PLC

03

CRC error User program CRC code does not match

04

Protect code error Protect code in the request message does not

05

Data range error Invalid data range designated

06

Timer/counter preset

07

value change error

Calendar/clock data error Invalid value written to calendar/clock

08

Data clear error Designated data cannot be cleared

09

Data error Invalid data other than 0 (30h) - 9 (39h) or

10

Setting error Incorrect setting for user communication

11

CPU module type code

12

error

Error Cause

is running

match that set in the PLC. Attempt was made to
enable protection on a protected user program.

Preset value change is attempted to timer or
counter with preset value designated by data reg­ister

A (41h) - F (46h)

CPU module type code in the request message
does not match the connected PLC.

Termi-

nator

(1)

The command code indicates whether the request command is completed normally or not and also whether another
reply message will be sent successively.

When reading a user program from the PLC, reply message 1 is returned in response to request message 1 and reply
message 2 is returned in response to request message 2. Reply message 1 contains command 1 (OK: continued) to
inform the computer that another reply message follows. All other reply messages contain command 0 (OK: discontin­ued) to indicate that no reply message follows when communication is completed normally.

When an OK reply is returned in response to request command R (read data), the read data is included in this place.

(2)

When an NG reply is returned, the cause of error exists in the PLC. See page 47.

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NAK Reply Message

When an error is found during communication, a NAK reply message is sent from the PLC to the computer.

NAK
Reply
Message

NAK

Device15h (1) (2) BCC

Termi-

nator

(1) Command 0 (no meaning): dummy data for consistent communication format

Depending on the communication error, an error code is set in this place.

(2)

Communication
error code
(2 bytes)

Error
Code

00

01

02
03
04

BCC error Appended BCC code does not match BCC calculated

Frame error Quantity of received bits differs from the preset

Data send/receive error Parity error or overrun error occurred.
Command error Unsupported request message is received.
Procedure/data quantity error Received request message does not match the

Error Type Error Contents

value of received data.

value (stop bit is 0 for example).

expected data (including quantity of data).

(1) The command code in the NAK reply message is always 0.
(2) The next two bytes indicate the communication error code.

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Write User Program in ASCII Format

The user program can be written from a computer to the PLC. When transferring a user program through modem, this
command is recommended to transfer the user program in ASCII format because modems understand ASCII codes.

When writing a user program from a computer, two request messages must be sent to the PLC.
Send request message 1 first. After confirming that the returned reply message is an OK reply, send request message 2.

Request Messages (Write User Program in ASCII Format)

Request Message 1

**05h

** 57h

(1) (2)

(1)
(2)
(3)

(4)
(5)

(6)

(7)

(8)
(9)

(3)

Communication control character 1 byte ENQ (05h) Enquiry
Communication device number 2 bytes
Continuation 1 byte 1 (31h) Continued

Command 1 byte W (57h) Write data
Data type 1 byte P (50h) User program in ASCII format

CPU module type code 1 byte

Program capacity 8 bytes

BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

(4)

50h

(5)

3*h

(6)

** ** **

** **

** ** ** **

(7)

00 - 1F
FF

0 (30h)
1 (31h)
2 (32h)
3 (33h)
4 (34h)
6 (36h)

0000 0000
:
FFFF FFFF

(8)

**31h

0Dh

(9)

Device number 0 through 31
Device number 255 (all devices)

10-I/O
16-I/O
20-I/O transistor output
24-I/O
40-I/O
20-I/O relay output

User program includes data of rung
comments and tag comments plus
function area settings. The function
area occupies 94 bytes.

Request Message 2

**05h

** ** ** ** ** **30h

(1) (2)

(1)
(2)
(3)
(4)
(5)

(6)

Note: The user program must be stored in a file of the ASCII code format. Ladder program files (.LDR) cannot be sent to the
PLC using this request message.

(3)

Communication control character 1 byte ENQ (05h) Enquiry
Communication device number 2 bytes
Continuation 1 byte 0 (30h) Discontinued
User program
BCC 2 bytes 00 - 7F Block check character

Terminator 1 byte CR (0Dh) Message end code

** ** ** **

(4)

Variable length
64,336 bytes max.

(5)

**

0Dh

(6)

00 - 1F
FF

0 (30h) - 9 (39h)
A (41h) - F (46h)

Device number 0 through 31
Device number 255 (all devices)

User program (ASCII code file)

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Reply Messages (Write User Program in ASCII Format)

OK Reply (Reply to Request Messages 1 and 2)

**06h

** **

(1) (2)

(1)
(2)
(3)
(4)
(5)

(3)

Communication control character 1 byte ACK (06h) Acknowledge
Communication device number 2 bytes 00 - 1F Device number 0 through 31
Command 1 byte 0 (30h) OK: Discontinued
BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

NG Reply (Reply to Request Message 1)

**06h

** 30h

32h

(1) (2)

(1)
(2)
(3)

(4)

(5)
(6)

(3)

Communication control character 1 byte ACK (06h) Acknowledge
Communication device number 2 bytes 00 - 1F Device number 0 through 31
Command 1 byte 2 (32h) NG

NG code 2 bytes

BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

(4)

(4)

**30h

0Dh

(5)

**

**3*h 0Dh

(5)

(6)

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01 (30h 31h)
02 (30h 32h)
03 (30h 33h)
04 (30h 34h)
12 (31h 32h)

Program capacity error
Protect error
RUN error
CRC error
CPU module type code error

Note: NG reply never occurs in response to reply message 2.

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Write User Program in Binary Format

The user program can be written from a computer to the PLC. This command can send a user program faster than the
Write User Program in ASCII format command.

When writing a user program from a computer, two request messages must be sent to the PLC.
Send request message 1 first. After confirming that the returned reply message is an OK reply, send request message 2.

Request Messages (Write User Program in Binary Format)

Request Message 1

**05h

** 57h

31h

(1) (2)

(1)
(2)
(3)

(4)
(5)

(6)

(7)

(8)
(9)

(3)

Communication control character 1 byte ENQ (05h) Enquiry
Communication device number 2 bytes
Continuation 1 byte 1 (31h) Continued

Command 1 byte W (57h) Write data
Data type 1 byte p (70h) User program in binary format

CPU module type code 1 byte

Program capacity 8 bytes

BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

(4)

70h

(5)

3*h

(6)

** ** **

** **

** ** ** **

(7)

00 - 1F
FF

0 (30h)
1 (31h)
2 (32h)
3 (33h)
4 (34h)
6 (36h)

0000 0000
:
FFFF FFFF

** 0Dh

(8)

(9)

Device number 0 through 31
Device number 255 (all devices)

10-I/O
16-I/O
20-I/O transistor output
24-I/O
40-I/O
20-I/O relay output

User program includes data of rung
comments and tag comments plus
function area settings. The function
area occupies 94 bytes.

Request Message 2

**05h

** ** ** ** ** **30h

(1) (2)

(1)
(2)
(3)
(4)
(5)

(6)

Note: The user program must be stored in a file of the binary code format. Ladder program files (.LDR) cannot be sent to the
PLC using this request message.

(3)

Communication control character 1 byte ENQ (05h) Enquiry
Communication device number 2 bytes
Continuation 1 byte 0 (30h) Discontinued
User program
BCC 2 bytes 00 - FF Block check character

Terminator 1 byte CR (0Dh) Message end code

** ** ** **

(4)

Variable length
32,168 bytes max.

(5)

**

0Dh

(6)

00 - 1F
FF

(00h) - (FFh) User program (binary code file)

Device number 0 through 31
Device number 255 (all devices)

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Reply Messages (Write User Program in Binary Format)

OK Reply (Reply to Request Messages 1 and 2)

**06h

** **

(1) (2)

(1)
(2)
(3)
(4)
(5)

(3)

Communication control character 1 byte ACK (06h) Acknowledge
Communication device number 2 bytes 00 - 1F Device number 0 through 31
Command 1 byte 0 (30h) OK: Discontinued
BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

NG Reply (Reply to Request Message 1)

**06h

** 30h

32h

(1) (2)

(1)
(2)
(3)

(4)

(5)
(6)

(3)

Communication control character 1 byte ACK (06h) Acknowledge
Communication device number 2 bytes 00 - 1F Device number 0 through 31
Command 1 byte 2 (32h) NG

NG code 2 bytes

BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

(4)

(4)

**30h

0Dh

(5)

**

**3*h 0Dh

(5)

(6)

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01 (30h 31h)
02 (30h 32h)
03 (30h 33h)
04 (30h 34h)
12 (31h 32h)

Program capacity error
Protect error
RUN error
CRC error
CPU module type code error

Note: NG reply never occurs in response to reply message 2.

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Read User Program in ASCII Format

The user program can be read from the PLC to a computer.
When reading a user program to a computer, two request messages must be sent from the computer to the PLC.

Send request message 1 first. After confirming that the returned reply message is an OK reply, send request message 2.
Specify a value larger than the user program capacity selected in the PLC in place of the program capacity in request mes-

sage 1. Reserve a buffer in the computer to store the data of the specified program capacity temporarily.

Request Messages (Read User Program in ASCII Format)

Request Message 1

**05h

** 52h

31h

(1) (2)

(1)
(2)
(3)

(4)
(5)

(6)

(7)

(8)
(9)

(3)

Communication control character 1 byte ENQ (05h) Enquiry
Communication device number 2 bytes
Continuation 1 byte 1 (31h) Continued

Command 1 byte R (52h) Read data
Data type 1 byte P (50h) User program in ASCII format

CPU module type code 1 byte

Program capacity 8 bytes

BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

(4)

50h

(5)

3*h

(6)

** ** **

** **

** ** ** **

(7)

00 - 1F
FF

0 (30h)
1 (31h)
2 (32h)
3 (33h)
4 (34h)
6 (36h)

0000 0000
:
FFFF FFFF

** 0Dh

(8)

(9)

Device number 0 through 31
Device number 255 (all devices)

10-I/O
16-I/O
20-I/O transistor output
24-I/O
40-I/O
20-I/O relay output

User program includes data of rung
comments and tag comments plus
function area settings. The function
area occupies 94 bytes.

Request Message 2

**05h

** 30h

(1) (2)

(1)
(2)
(3)

(4)
(5)
(6)

(3)

(4)

Communication control character 1 byte ENQ (05h) Enquiry
Communication device number 2 bytes
Continuation 1 byte 0 (30h) Discontinued

Command 1 byte R (52h) Read data
BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

**

**52h

0Dh

(5)

(6)

M

ICROSMART

00 - 1F
FF

Device number 0 through 31
Device number 255 (all devices)

11

Reply Messages (Read User Program in ASCII Format)

OK Reply

• Reply Message 1

**06h

** 31h

(1) (2)

(1)
(2)
(3)

(4)

(5)

(6)
(7)

(3)

Communication control character 1 byte ACK (06h) Acknowledge
Communication device number 2 bytes 00 - 1F Device number 0 through 31
Command 1 byte 1 (31h) OK: Continued

CPU module type code 1 byte

Program capacity 8 bytes

BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

3*h

(4)

** ** **

** **

** ** ** **

(5)

** 0Dh

(6)

M

ICROSMART COMMUNICATION PROTOCOL

(7)

0 (30h)
1 (31h)
2 (32h)
3 (33h)
4 (34h)
6 (36h)

0000 0000
:
FFFF FFFF

10-I/O
16-I/O
20-I/O transistor output
24-I/O
40-I/O
20-I/O relay output

User program includes data of rung
comments and tag comments plus
function area settings. The function
area occupies 94 bytes.

• Reply Message 2

**06h

** ** ** ** ** **30h

(1) (2)

(1)
(2)
(3)

(4)
(5)

(6)

(3)

Communication control character 1 byte ACK (06h) Acknowledge
Communication device number 2 bytes 00 - 1F Device number 0 through 31
Command 1 byte 0 (30h) OK: Discontinued

User program
BCC 2 bytes 00 - 7F Block check character

Terminator 1 byte CR (0Dh) Message end code

** ** ** **

(4)

Variable length
64,336 bytes max.

(5)

**

0Dh

(6)

0 (30h) - 9 (39h)
A (41h) - F (46h)

Note: The received user program is stored on the disk in the ASCII code format.

NG Reply (Reply to Request Message 1)

**06h

** 30h

32h

(1) (2)

(1)
(2)
(3)

(4)

(5)
(6)

(3)

Communication control character 1 byte ACK (06h) Acknowledge
Communication device number 2 bytes 00 - 1F Device number 0 through 31
Command 1 byte 2 (32h) NG

NG code 2 bytes

BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

(4)

**

**3*h 0Dh

(5)

(6)

01 (30h 31h)
02 (30h 32h)
04 (30h 34h)

User program (ASCII code file)

Program capacity error
Protect error
CRC error

Note: NG reply never occurs in response to reply message 2.

M

ICROSMART

12

M

ICROSMART COMMUNICATION PROTOCOL

Read User Program in Binary Format

The user program can be read from the PLC to a computer.
When reading a user program to a computer, two request messages must be sent from the computer to the PLC.

Send request message 1 first. After confirming that the returned reply message is an OK reply, send request message 2.
Specify a value larger than the user program capacity selected in the PLC in place of the program capacity in request mes-

sage 1. Reserve a buffer in the computer to store the data of the specified program capacity temporarily.

Request Messages (Read User Program in Binary Format)

Request Message 1

** 52h

31h

(1) (2)

Communication control character 1 byte ENQ (05h) Enquiry

(1)

Communication device number 2 bytes

(2)

Continuation 1 byte 1 (31h) Continued

(3)

Command 1 byte R (52h) Read data

(4)

Data type 1 byte p (70h) User program in binary format

(5)

CPU module type code 1 byte

(6)

Program capacity 8 bytes

(7)

BCC 2 bytes 00 - 7F Block check character

(8)

Terminator 1 byte CR (0Dh) Message end code

(9)

(3)

(4)

Request Message 2

70h

(5)

3*h

(6)

** ** **

** **

** ** ** ****05h

(7)

00 - 1F
FF

0 (30h)
1 (31h)
2 (32h)
3 (33h)
4 (34h)
6 (36h)

0000 0000
:
FFFF FFFF

** 0Dh

(8)

(9)

Device number 0 through 31
Device number 255 (all devices)

10-I/O
16-I/O
20-I/O transistor output
24-I/O
40-I/O
20-I/O relay output

User program includes data of rung
comments and tag comments plus
function area settings. The function
area occupies 94 bytes.

**05h

** 30h

(1) (2)

(1)
(2)
(3)

(4)
(5)
(6)

(3)

Communication control character 1 byte ENQ (05h) Enquiry
Communication device number 2 bytes
Continuation 1 byte 0 (30h) Discontinued

Command 1 byte R (52h) Read data
BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

(4)

**

**52h

0Dh

(5)

(6)

M

ICROSMART

00 - 1F
FF

Device number 0 through 31
Device number 255 (all devices)

13

Reply Messages (Read User Program in Binary Format)

OK Reply

• Reply Message 1

**06h

** 31h

(1) (2)

(1)
(2)
(3)

(4)

(5)

(6)
(7)

(3)

Communication control character 1 byte ACK (06h) Acknowledge
Communication device number 2 bytes 00 - 1F Device number 0 through 31
Command 1 byte 1 (31h) OK: Continued

CPU module type code 1 byte

Program capacity 8 bytes

BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

3*h

(4)

** ** **

** **

** ** ** **

(5)

** 0Dh

(6)

M

ICROSMART COMMUNICATION PROTOCOL

(7)

0 (30h)
1 (31h)
2 (32h)
3 (33h)
4 (34h)
6 (36h)

0000 0000
:
FFFF FFFF

10-I/O
16-I/O
20-I/O transistor output
24-I/O
40-I/O
20-I/O relay output

User program includes data of rung
comments and tag comments plus
function area settings. The function
area occupies 94 bytes.

• Reply Message 2

**06h

** ** ** ** ** **30h

(1) (2)

(1)
(2)
(3)

(4)
(5)

(6)

(3)

Communication control character 1 byte ACK (06h) Acknowledge
Communication device number 2 bytes 00 - 1F Device number 0 through 31
Command 1 byte 0 (30h) OK: Discontinued

User program
BCC 2 bytes 00 - FF Block check character

Terminator 1 byte CR (0Dh) Message end code

** ** ** **

(4)

Variable length
32,168 bytes max.

(5)

**

0Dh

(6)

(00h) - (FFh) User program (binary code file)

Note: The received user program is stored on the disk in the binary code format.

NG Reply (Reply to Request Message 1)

**06h

** 30h

32h

(1) (2)

(1)
(2)
(3)

(4)

(5)
(6)

(3)

Communication control character 1 byte ACK (06h) Acknowledge
Communication device number 2 bytes 00 - 1F Device number 0 through 31
Command 1 byte 2 (32h) NG

NG code 2 bytes

BCC 2 bytes 00 - 7F Block check character
Terminator 1 byte CR (0Dh) Message end code

(4)

**

**3*h 0Dh

(5)

(6)

01 (30h 31h)
02 (30h 32h)
04 (30h 34h)

Program capacity error
Protect error
CRC error

Note: NG reply never occurs in response to reply message 2.

M

ICROSMART

14

M

Calendar/clock

operand number

Data

0000
0001
0002
0003
0004
0005
0006

Year
Month
Day
Day of week
Hour
Minute
Second

ICROSMART COMMUNICATION PROTOCOL

Write N Bytes

Data can be written into N-bytes of operands starting with the specified operand number in the PLC.
This command can be used to turn on or off bit operands such as inputs, outputs, internal relays, and shift register bits in

units of 8 bits.
This command can also be used to change timer and counter preset values, enter data into data registers, and set calendar/

clock data.

Request Message (Write N Bytes)

**05h

(1) (2)

(1)
(2)
(3)

(4)
(5)
(6)

(7)

(8)
(9)

(10)

** ** **30h

Communication control character 1 byte ENQ (05h) Enquiry
Communication device number 2 bytes
Continuation 1 byte 0 (30h) Discontinued

Command 1 byte W (57h) Write data
Data type 1 byte See table below. N-byte designation
Operand number 4 bytes See table below. First operand number to write to

Data length (n) 2 bytes 00 - C8

Data
BCC 2 bytes 00 - 7F Block check character

Terminator 1 byte CR (0Dh) Message end code

(3)

57h

(4)

(5)

** ** **

(6)

****

**

**

(7)

2n bytes
1 ≤ n ≤ 200

** ** ** **

(8)

Data for 1-byte operand after ASCII conversion

00 - 1F
FF

0 (30h) - 9 (39h)
A (41h) - F (46h)

**

0Dh

(9)

(10)

Device number 0 through 31
Device number 255 (all devices)

Byte count of data to write
200 (C8h) bytes maximum

Data to write

X (58h)
Y (59h)

M (4Dh)

R (52h)
T (54h)

t (74h)
C (43h)
c (63h)
D (44h)

W (57h)

Note: The valid operand range depends on the CPU module type. For details, see page 48.

Operand numbers for calendar and clock are allocated as listed on the right:

When the range specified by the data type and data length is invalid, the PLC
returns an NG reply.

When a data register is designated as a preset value for a timer or counter, data
cannot be written into the preset value. To change the preset value, write data
into the data register designated as a preset value.

(5) Data type code (6) Operand number (Note) Remarks

Input
Output
Internal relay

Shift register
Timer (preset value)
Timer (current value)
Counter (preset value)
Counter (current value)
Data register
Calendar/clock

0000 - 0307
0000 - 0307

0000 - 1277, 8000 - 8077

0000 - 0127
0000 - 0099
0000 - 0099
0000 - 0099
0000 - 0099

0000 - 1299, 2000 - 7999, 8000 - 8199

0000 - 0006

M

ICROSMART

The least significant digit of the oper­and number is an octal number (0-7).
Upper digits are decimal numbers.

All four digits of the operand number
are decimal numbers.

15