TOHO ELECTRONICS TTX-700 User Manual
TOHO ELECTRONICS INC.
Operation Manual, Communications
(TOHO protocol and MODBUS)
Model: TTX-700
Designation: Module Controller
Contents
1. Before using the product......................................................................................................................... 4
1.1 On this operation manual .............................................................................................................4
1.2 What can be done with communications......................................................................................4
1.3 Positioning communications (priority ranking)............................................................................ 4
1.4 Setting before communications.................................................................................................... 4
2. Settings regarding TOHO communications ............................................................................................5
2.1 Overview...................................................................................................................................... 5
2.2 Setting a data length..................................................................................................................... 6
2.3 Setting a stop bit length................................................................................................................ 6
2.4 Setting a parity .............................................................................................................................6
2.5 Setting whether to conduct a BCC check..................................................................................... 6
2.6 Setting a communications speed ..................................................................................................6
2.7 Setting an address......................................................................................................................... 7
2.8 Setting a response delay............................................................................................................... 7
2.9 Switching communications mode ................................................................................................ 7
3. TOHO communications control.............................................................................................................. 8
3.1 Communications procedure.......................................................................................................... 8
3.2 Message types .............................................................................................................................. 8
3.3 Composition of a request message
(transmitted from a high-level computer to this product)............................................................. 9
3.4 Composition of a response message
(transmitted from this product to a high-level computer)........................................................... 10
3.5 Description of codes....................................................................................................................11
3.6 Communications precautions .....................................................................................................13
4. Examples of TOHO communications ...................................................................................................15
4.1 Examples of communications to be read.................................................................................... 15
4.2 Examples of communications to be written............................................................................... 15
5. Settings regarding MODBUS communications.................................................................................... 17
5.1 Overview.................................................................................................................................... 17
5.2 Setting a data length................................................................................................................... 18
5.3 Setting a stop bit length.............................................................................................................. 18
5.4 Setting a parity ........................................................................................................................... 18
5.5 Setting a communications speed ................................................................................................18
5.6 Setting an address....................................................................................................................... 19
5.7 Setting a response delay............................................................................................................. 19
5.8 Switching communications mode .............................................................................................. 19
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6 MODBUS communications control...................................................................................................... 20
6.1 Communications procedure........................................................................................................ 20
6.2 Message types ............................................................................................................................ 20
6.3 Composition of an RTU request message
(transmitted from a high-level computer to this product)........................................................... 21
6.4 Composition of an RTU response message
(transmitted from this product to a high-level computer)........................................................... 22
6.5 Description of RTU codes.......................................................................................................... 23
6.6 Precautions on RTU communications ........................................................................................25
6.7 Example of CRC-16 calculations ...............................................................................................26
6.8 Composition of an ASCII request message
(transmitted from a high-level computer to this product)........................................................... 27
6.9 Composition of ASCII response messages
(transmitted from this product to a high-level computer)...........................................................28
6.10 Description of ASCII codes........................................................................................................ 30
6.11 Precautions on ASCII communications...................................................................................... 32
6.12 Example of LRC calculations..................................................................................................... 33
7. Specifications........................................................................................................................................ 34
7.1 Communications standard category: Compliant with EIA standard RS-485 .............................34
7.2 Communications specifications.................................................................................................. 34
8. Connections........................................................................................................................................... 35
8.1 Connections for the RS-485....................................................................................................... 35
9. Table of ASCII codes............................................................................................................................ 36
10. Table of identifiers (codes).................................................................................................................... 37
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1. Before using the product
1.1 On this operation manual
This is an operation manual regarding communications with a TTX-700 (hereinafter referred to as
"this product").
1.2 What can be done with communications
With this product, users can write and read items specified in "10. Table of identifiers," such as
"reconfiguring, starting, or stopping items that are operable with the front keys" and "reading
information displayable on the display."
However, reading and writing with ordinary commands are performed with regarding to the RAM in
this product. Written data can be turned back into the values before the writing (the values stored on
the EEPROM) by turning power off and on again. To store the written data on the EEPROM of this
product, execute a store request message. (See "3.6. Communications precautions.")
Settings regarding options not added and other unnecessary settings cannot be read or written.
1.3 Positioning communications (priority ranking)
Data and parameters in this product can be changed with keys while in operation in the
communications mode.
While this product is in operation in the RO (read-only) mode, no data or parameter setting can be
changed by communications. (Provided that communications modes can be changed.)
1.4 Setting before communications
Before performing communications, this product must be set.
This product is compatible with the TOHO communications protocol and the MODBUS
communications (RTU, ASCII).
Select a protocol with the protocol setting ( ) on communications 1/2 setting ( ). For the
TOHO communications protocol, see "2. Settings regarding TOHO communications." For the
MODBUS communications protocol, see "5. Settings regarding MODBUS communications."
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2. Settings regarding TOHO communications
2.1 Overview
Before communications is performed, initial settings must be made on this product. Enter such
settings with the keys on the front panel. To switch to a series of setting screens, take the steps
described below. For details, see the operation manual furnished with this product.
Power ON
Initial setting
Operation mode screen
MODE key at least 2 seconds
(Setting mode selection screen)
▲ ▼key
MODE key
MODE key
MODE key
MODE key
MODE key
MODE key
Select a communications setting mode
Set a communications protocol
Set a communications parameter
Set a communications speed
Set a communications address
Set a communications response delay
Set communications mode switchover
MODE key
When the settings are over, press the MODE key at least 2 seconds to go back to the operation mode.
The parameters indicated above are initial values.
５
2.2 Setting a data length
2.3 Setting a stop bit length
2.4 Setting a parity
2.5 Setting whether to conduct a BCC check
While in the "Set a communications parameter" screen on the preceding page, operate the ▲ and
▼ keys to make the settings.
The initial value is [ ].
Stop bit 1
Stop bit 2
No parity
Odd parity
Even parity
Data length, 7 bits
Data length, 8 bits
BCC check disabled
BCC check enabled
2.6 Setting a communications speed
While in the "Set a communications speed" screen on the preceding page, operate the ▲ and ▼
keys to make the settings.
The initial value is [ ].
１２００ｂｐｓ
２４００ｂｐｓ
４８００ｂｐｓ
９６００ｂｐｓ
１９２００ｂｐｓ
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2.7 Setting an address
While in the "Set a communications address" screen on the preceding page, operate the ▲ and ▼
keys to make the settings.
The initial value is •.
Setting range: 1 to 99 stations (It cannot be set to a 0.)
2.8 Setting a response delay
Set a time from the time when the high-level computer finished sending a "request message" until
the time when it delivers the line and enters an input state.
While in the "Set a response delay" on the preceding page, operate the ▲ and ▼ keys to make the
settings.
The initial value is 0.
Setting range: 0 to 250ms
* If the response delay is set to a short setting, the communications may not be conducted normally.
* In a real operation, the processing time for this product will be added, in addition to the response
delay.
2.9 Switching communications mode
While in the "Set communications mode switchover" screen on the preceding page, operate the ▲
and ▼ keys to make the settings.
Read only
Read and write
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3. TOHO communications control
3.1 Communications procedure
This product returns a "response message" in response to a "request message" from a high-level
computer. It therefore does not initiate a transmission.
Transmitted by a high-
level computer
High-level computer
This product
See "2.8. Set a response delay."
See "3.6.1. Communications timing."
Request message
Response delay:
0-250ms
Transmitted by this
product
Request message
3.2 Message types
n Messages are roughly divided into the following types:
Request message (transmitted
from a high-level computer)
Read request message
Transmitted by a high-
level computer
Request message
1ms or more
See 3.6.2. "Interval between requests."
Response message (transmitted
from this product)
Receipt acknowledgement and data
response
Transmitted by this
product
Request message
Write complete response
Write request message
Reception error and error description
response
Store request message
: Response when a normal "request message" is received
: When a received "request message" contains an error
Store complete response
n All codes (except for BCC) from STX data to ETX are expressed in ASCII codes.
n In assembling a program for a high-level computer, see "10. Table of identifiers (codes)" and "9.
Table of ASCII codes" at the end of the book.
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3.3 Composition of a request message (transmitted from a high-level
computer to this product)
n For codes ① to ⑩, see "3.5. Description of codes."
n For specific examples of request messages, see "4.1. Examples of reading communications" and
"4.2. Examples of writing communications."
3.3.1 Composition of a read request message
ＳＴＸ
□
□
□
Ｒ
①
②
Start code
Address③Contents of the
｜
request: read/write
□
④
Identifier
ＥＴＸ
□
｜
⑥
End code
BCC data
ＢＣＣ
⑦
3.3.2 Composition of a write request message
ＳＴＸ
□
□
□
□
□
□
Ｗ
①
②
Start code
Address③Contents of the
request: read/write
3.3.3 Composition of a store request message
④
｜
Identifier
□
｜
｜
ＳＴＸ
□
□
Ｗ
Ｓ
Ｔ
①
②
Start code
request: read/write
Address③Contents of the
④
｜
Identifier
ＥＴＸ
□
□
□
⑥
｜
｜
⑤
｜
Numerical data
ＥＴＸ
End code
ＢＣＣ
Ｒ
｜
⑥
⑦
End code
BCC data
ＢＣＣ
⑦
BCC data
９
3.4 Composition of a response message (transmitted from this product to a
high-level computer)
n For codes ① through ⑩, see "3.5. Description of codes."
n For specific examples of request messages, see "4.1. Examples of communications to be read"
and "4.2. Examples of communications to be written."
3.4.1 Response message in response to a read request message
ＳＴＸ
①
Start code
ＡＣＫ
□
□
□
②
⑧
｜
Address
Acknowledge code
□
□
□
｜
④
Identifier
｜
□
□
□
□
｜
｜
⑤
｜
Numerical data
End code
ＢＣＣ
ＥＴＸ
⑥
⑦
BCC data
3.4.2 Response message in response to a write/store request message
ＳＴＸ
①
Start code
3.4.3 Response message in the case of an error
ＳＴＸ
□
①
Start code
Address⑥End code
ＡＣＫ
ＢＣＣ
□
②
Address⑥End code
□
②
acknowledge code
ＥＴＸ
□
⑦
⑧
BCC data
Acknowledge code
ＮＡＫ
ＢＣＣ
ＥＴＸ
□
⑩
⑦
BCC data
⑨
Negative
Error code
１０
3.5 Description of codes
n The codes from ① STX, ② address to ⑩ ERR as indicated below are expressed in ASCII
codes.
n For the ASCII codes, see "9. Table of ASCII codes."
n For conversion to ASCII codes, see "4. Examples of TOHO communications."
① STX
This code is needed for the receiver to detect the top of the message. It is affixed to the top
of a character string to be sent.
② Address
This is the address of the party (this product) with whom a high-level computer
communicates. The address in the response message from this product indicates the sender
of the response message. Note that, when CH2 is used, two addresses are occupied. (Setting
ADR to 1 causes this product to occupy addresses 1 and 2.)
③ Contents requested
Enter a code R or W.
R: to read data from this product
W: to write or store data in this product
④ Identifier
An identifier is a classification code (identifier) for data to be read or written and expressed
in a three-digit alphanumerical ASCII code. See "10. Table of identifiers (codes)."
⑤ Numerical data
At the time of writing or reading, 5-digit numerical data can be written.
Example: The table below indicates the significances of 5-digit numerical data 00010.
Example Significance of the value
Proportional band (P) →1.0%
Data (PV), etc, whose decimal point can be shifted
When the decimal point setting (DP) is 0 10
When the decimal point setting (DP) is 0.1 1.0
If DP = 0.1, the numerical data "12000" means 1200.0. In the case of text data, it is "□□INP." (The □
is a space.)
⑥ ETX
This code is needed for the receiver to detect the end of a message. It is affixed to the end of
a character string to be sent (except for BCC).
⑦ BCC
This is a check code for error detection and is the exclusive OR (EX-OR) of all characters
from STX to ETX.
If the BCC check is set to "Disabled" in the communications settings in this product, this
code (BCC) will not be incorporated in the response message. See "2. Settings regarding
TOHO communications."
１１
⑧ ACK
It is an acknowledge code. If a message received by this product is error-free, this code will
be incorporated in the "response message" from this product and returned.
⑨ NAK
It is a negative acknowledge code. If a "request message" received by this product is
error-ridden, this code will be incorporated in the "response message" from this product and
returned.
If the "request message" received is error-ridden, the error contents (⑩ ERR type) will be
incorporated in the "response message" from this product, following NAK.
⑩ ERR type
If a "request message" received from this product is error-ridden, the error contents (either
of the numbers in the table below) will be incorporated in the "response message" from this
product, following "⑨ NAK."
The error number 0 is an instrument error (memory error or A/D conversion error). It will
be incorporated in the "response message" regardless of whether there is an error in the
"request message."
The error number 9 is an AT error. It will therefore be incorporated in the "response
message" regardless of whether there is an error in the "request message." Remove the
cause of the error immediately and start the AT again.
If there are two or more errors occurring at the same time, the largest error number will be
incorporated.
The table below indicates the error contents and classifications.
Error No.
0 Instrument error (memory error or A/D conversion error)
1 The numerical data deviated from the "range of settings designated specifically with setting
items."
2 The change of requested items is disabled or there are no items to be read.
3 An ASCII code other than the numerical data was specified in the field of numerical data.
An ASCII code other than numbers and "-" was specified in the field of codes.
4 Format error
5 BCC error
6 Overrun error
7 Framing error
8 Parity error
9 A PV error occurred during AT. Or AT will not end 3 hours later.
Error contents in the "request message" received by this product
１２
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