RTU-485
Modbus Remote I/O Communication Module
Application Manual
Modbus Remote I/O Communication Module RTU-485
Warning
3
Please read this instruction carefully before use and follow this instruction to operate the device in order to prevent
damages on the device or injuries to staff.
3
Switch off the power before wiring.
3
RTU-485 is an OPEN TYPE device and therefore should be installed in an enclosure free of airborne dust, humidity,
electric shock and vibration. The enclosure should prevent non-maintenance staff from operating the device (e.g.
key or specific tools are required for operating the enclosure) in case danger and damage on the device may occur.
3
RTU-485 is to be used for controlling the operating machine and equipment. In order not to damage it, only
qualified professional staff familiar with the structure and operation of RTU-485 can install, operate, wire and
maintain it.
3
DO NOT connect input AC power supply to any of the I/O terminals; otherwise serious damage may occur. Check
all the wirings again before switching on the power and DO NOT touch any terminal when the power is switched
on. Make sure the ground terminal
1 INTRODUCTION...................................................................................................................................3
2 PRODUCT PROFILE & OUTLINE .......................................................................................................4
3 BASIC OPERATI ON.............................................................................................................................6
Table of Contents
1.1 Features......................................................................................................................................3
1.2 Specifications..............................................................................................................................3
2.1 Dimension ...................................................................................................................................4
2.2 Product Profiles...........................................................................................................................4
2.3 RUN/STOP Switch......................................................................................................................4
2.4 Address Switch ...........................................................................................................................5
2.5 Communication Mode Switch......................................................................................................5
3.1 Connecting RTU-485 to DVP Slim DI/DO Extension Unit...........................................................6
is correctly grounded in order to prevent electromagnetic interference.
3.2 Installing RTU-485 and DVP Slim DI/DO on DIN Rail.................................................................6
4 AREAS FOR SPECIAL FUNCTIONS ..................................................................................................6
4.1 Areas in Slim DI/DO Extension Unit............................................................................................6
4.2 Areas in Special Module..............................................................................................................7
4.3 Special Functions........................................................................................................................7
4.4 Error Codes.................................................................................................................................8
5 FUNCTION CODES RTU-485 SUPPORTS .........................................................................................8
6 APPLICATI ON OF RTU-485 ................................................................................................................9
6.1 Connection between RTU-485 and Master Device.....................................................................9
6.2 Application Example....................................................................................................................9
DVP-PLC Application Manual
1
Modbus Remote I/O Communication Module RTU-485
7 LED INDICATOR & TROUBLE-SHOOTING ..................................................................................... 11
7.1 POWER LED.............................................................................................................................11
7.2 RUN LED...................................................................................................................................11
7.3 ALARM LED..............................................................................................................................11
7.4 RS-485 LED ............................................................................................................................. 12
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DVP-PLC Application Manual
Modbus Remote I/O Communication Module RTU-485
1 Introduction
1. To ensure correct installation and operation of RTU-485, please read this chapter carefully before using your
RTU-485
2. RTU-485 is a Modbus remote I/O communication module for Delta’s PLC to remote-control DVP Slim series
DI/DO and AI/AO extension module s.
3. RTU-485 is a standard Modbu s slave device and is compatible with pther master devices which comply with
Modbus protocol.
1.1 Features
y
Auto-detecting extension modules
y Maximum extension: 8 special modules; 128 input points and 128 output points
1.2 Specifications
DeviceNet connection
Transmission method RS-485
Electrical isolation 500 VDC
Interface Removable connector (3Pin)
Transmission cable 2-wire twister shielded cablew8
Communication
7, E, 1 7, O, 2 8, O, 1
Mode
Baud rates
Electrical specification
Power supply 24 VDC (-15% ~ 20%) (with DC input polarity reverse protection)
Environment
Noise immunity
Operation 0ºC ~ 55ºC (temperature); 50 ~ 95% (humidity); pollution degree 2
ASCII
RTU 8, E, 1 8, O, 1 8, N, 1 8, N, 2
1,200bps; 2,400bps; 4,800bps; 9,600bps; 19,200bps; 38,400bps;
57,600bps; 115,200bps
ESD (IEC 61131-2, IEC 61000-4-2): 8KV Air Discharge，4KV Contact
Discharge
EFT (IEC 61131-2, IEC 61000-4-4): Power Line: 2KV, Digital I/O: 1KV
Analog & Communication I/O: 1KV
Damped-Oscillatory Wav e: Power Line: 1KV, Digital I/O: 1KV
RS (IEC 61131-2, IEC 61000-4-3): 80MHz~1000MHz , 1.4GHz~2.0GHz ,
10V/m
7, O, 1 7, N, 2 8, N, 1
7, E, 2 8, E, 1 8, N, 2
Storage -25ºC ~ 70ºC (temperature); 5 ~ 95% (humidity)
Vibration/shock
resistance
Certificates IEC 61131-2, UL508
DVP-PLC Application Manual
Standard: IEC 61131-2、IEC 68-2-6 (TEST Fc)/IEC 61131-2 & IEC 68-2-27
(TEST Ea)
3
Modbus Remote I/O Communication Module RTU-485
2 Product Profile & Outline
2.1 Dimension
2.2 Product Profiles
1. POWER indicator 9. Mounting hole for extension module
2. RUN indicator 10. Nameplate
3. ALARM indicator 11. Extension port
4. RUN/STOP switch 12. DIN rail (35mm)
5. Communication indicator 13. Fastening hole for extension module
6. Address switch 14. DIN rail clip
7. Communication mode switch 15. Mounting rail for extension module
8. RS-485 communication port 16. Power input
2.3 RUN/STOP Switch
RUN/STOP action Explanation
RUN Special module in RUN mo de
RUN → STOP
STOP
STOP → RUN
1. Special module switches from RUN to STOP.
2. Output points on Slim DI/DO extension unit all turn Off.
1. Special module in STOP mode
2. Special module cannot be controlled by communication.
3. Slim DI/DO extension unit cannot be controlled by
communication.
1. Special module switches from STOP to RUN.
2. RTU-485 redetects the number of point s in Slim DI/DO
and the number of special modules.
RUN
STOP
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DVP-PLC Application Manual
2.4 Address Switch
The switch is used on setting up the communication address of RTU-485. Range: H’01 ~ H’F0 (decimal: 1 ~
240)
Switch setting Content
Modbus Remote I/O Communication Module RTU-485
H’01 ~ H’F0
H’00,
H’F1 ~ H’FF
Example: If you need to set the address of RTU-485 to 26, swich the DIP switch corresponding to ID4 to “ON”,
switch corresponding to ID3 to “ON” and switch corresponding to ID1 to “ON”.
Note:
z Please set up the address when the power of RTU-485 is switched of f. After the setup is completed, re-powe r
RTU-485.
z When RTU-485 is operating, changing the setting of communication address will be invalid.
z Use slotted screwdriver to adjust the switch carefully in case you scratch the switch.
2.5 Communication Mode Switch
These switches are for:
z Setting up communication format (PA0 ~ PA3, A/R)
z Setting up baud rate (DR0 ~ DR2)
PA3 PA2 PA1 PA0 A/R Format
Valid communication address
ID0 ~ ID7 are defined as: 2
Invalid communication address
0
, 21, 22, …26, 27
OFF OFF OFF OFF ON 7,E,1, ASCII
OFF OFF OFF ON ON 7,O,1, ASCII
OFF OFF ON OFF ON 7,E,2, ASCII
OFF OFF ON ON ON 7,O,2, ASCII
OFF ON OFF OFF ON 7,N,2, ASCII
OFF ON OFF ON ON 8,E,1, ASCII
OFF ON ON OFF ON 8,O,1, ASCII
OFF ON ON ON ON 8,N,1, ASCII
PA3 PA2 PA1 PA0 A/R Format
ON OFF OFF OFF ON 8,N,2, ASCII
OFF ON OFF ON OFF 8,E,1, RTU
OFF ON ON OFF OFF 8,O,1, RTU
OFF ON ON ON OFF 8,N,1, RTU
ON OFF OFF OFF OFF 8,N,2, RTU
DR2 DR1 DR0 Baud rate (bps)
OFF OFF OFF 1,200
OFF OFF ON 2,400
OFF ON OFF 4,800
OFF ON ON 9,600
ON OFF OFF 19,200
DVP-PLC Application Manual
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Modbus Remote I/O Communication Module RTU-485
ON OFF ON 38,400
ON ON OFF 57,600
ON ON ON 115,200
Note:
z Please set up the switch when the power is switched off. After the setup is completed, re-power R TU-485.
z When RTU-485 is operating, changing the setting of the switch will be invalid.
z Use slotted screwdriver to adjust the switch carefully in case you scratch the switch.
3 Basic Operation
3.1 Connecting RTU-485 to DVP Slim DI/DO Extension Unit
z Open the fixing clips on top and bottom of RTU-485. Meet the extension port of Slim DI/DO with R TU-485.
z Press the fixing clips on top and bottom of Slim DIDO and check if the connection is fine.
POWER
RUN
ALARM
RS-485
ID7
ID6
ID5
RUN
ID4
ID3
ID2
ID1
ID0
STOP
P
PA3
PA2
5
PA1
8
PA0
4
DR2
-
DR1
U
DR0
T
A/R
R
P
S
S
6
6
1
1
-
P
P
V
V
D
D
A
A
D
D
2
2
0
0
-
P
P
V
V
D
D
3.2 Installing RTU-485 and DVP Slim DI/DO on DIN Rail
z Use 35mm DIN rail.
z Open the DIN rail clip on RTU-485 and Slim DI/DO. Insert RTU-4 85 and Slim DI/DO onto the DIN rail.
z Clip up the DIN rail clips on RTU-485 and Slim DI/DO to fix them on the DIN rail, as shown below.
POWER
RUN
ALARM
RS-48 5
ID7
ID6
ID5
ID4
ID3
ID2
ID1
ID0
P
PA3
PA2
5
8
4
U
T
R
S
PA1
6
PA0
1
DR2
-
DR1
DR0
P
A/R
V
D
A
D
2
0
P
V
D
4 Areas for Special Functions
4.1 Areas in Slim DI/DO Extension Unit
Communication
address
H’0400 ~ H’047F X: X000 ~ X177 (Octal) R bit 128 points
H’0500 ~ H’057F Y: Y000 ~ Y177 (Octal) R/W bit 128 points
Devices Attribute Data type Length
35mm DIN rail
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DVP-PLC Application Manual
4.2 Areas in Special Module
Modbus Remote I/O Communication Module RTU-485
Communication
address
H’1600 ~ H’1630 1st special module: CR0 ~ CR48 word 49
H’1640 ~ H’1670 2nd special module: CR0 ~ CR48 word 49
H’1680 ~ H’16B0 3rd special module: CR0 ~ CR48 word 49
H’16C0 ~ H’16F0 4th special module: CR0 ~ CR48 word 49
H’1700 ~ H’1730 5th special module: CR0 ~ CR48 word 49
H’1740 ~ H’1770 6th special module: CR0 ~ CR48 word 49
H’1780 ~ H’17B0 7th special module: CR0 ~ CR48 word 49
H’17C0 ~ H’17F0 8th special module: CR0 ~ CR48
Note:
Maximum 8 special modules are connectible to RTU-485. The first special module connected is the nearestone
on the right hand side of RTU-485, and so on.
4.3 Special Functions
Communication
address
H’0000 R Model name
H’0001 R Firmware version
H’0002 R Issue date
H’0003 R/W RUN/STOP RTU-485
H’0004 R Communication format
H’0005 R Baud rate Displaying the baud rate of RTU-485.
H’0006 R
H’0007 R
H’0008 R Error code
H’0009 R Historical error code
H’0017 R
H’0018 R
H’0019 R
H’001A R
H’001B R
Attribute Content Explanation
Devices Attribute Data type Length
Please refer to
theCR attribute of
each special
module.
word 49
Set up by the system. Model code of RTU-485 =
H’0200.
The current firmware version is displayed in hex,
e.g. V0.1 is indicated as H’0010.
The issue data of the firmware is displayed in
hex, e.g. H’1FD0 = K8150 indicates that the
firmware is issued on the morning of August 15.
H’0003 = K1, RTU-485 RUN;
H’0003 = K0, RTU-485 STOP.
Displaying the communication format of
RTU-485.
Communication
address
Number of DI/DO
points
Number of special
modules
Model code of the 1
special module
Model code of the 2
special module
Model code of the 3
special module
Model code of the 4
special module
Displaying the communication address of
RTU-485.
High byte stores the number of input points. Low
byte stores the number of output points.
Recording the current error. See 17.4.4 for the
meaing of error codes.
The number of errors occurring.
Range: 0 ~ 32
The number of special modules RTU-485
detects.
st
The model code of the 1st special module
connected to RTU-485.
nd
The model code of the 2nd special module
connected to RTU-485.
rd
The model code of the 3rd special module
connected to RTU-485.
th
The model code of the 4th special module
connected to RTU-485.
DVP-PLC Application Manual
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Modbus Remote I/O Communication Module RTU-485
Communication
address
H’001C R
H’001D R
H’001E R
H’001F R
4.4 Error Codes
Code Indication Explanation
0001 Incorrect function code RTU-485 does not support this function code.
0002 Incorrect operand address
0003 Incorrect data The data read/written exceed the maximum length.
0004 RTU-485 STOP RTU-485 in STOP mode.
000B Incorrect communication format The length of data received by RTU-485 is too short.
000C Incorrect communication format The length of data received by R TU-485 is too long.
Attribute Content Explanation
Model code of the 5
special module
Model code of the 6
special module
Model code of the 7
special module
Model code of the 8
special module
th
The model code of the 5th special module
connected to RTU-485.
th
The model code of the 6th special module
connected to RTU-485.
th
The model code of the 7th special module
connected to RTU-485.
th
The model code of the 8th special module
connected to RTU-485.
The address of a certain device is not within the
range, orthe data written into it are incorrect.
5 Function Codes RTU-485 Supports
RTU-485 complies with the standard Modbu s proto col, suppo rting 7 function codes, whi ch are H’01, H’02, H’03,
H’05, H’06, H’0F and H’10. Please refer to the standard Modbus protocol for the specific data format of each
function code.
Code Function Data type Applicable address
H’01
H’02
Reading the output status of bit
device.
Reading the input status of bit
device
bit DO area: H’0500 ~ H’057F
word bit DI area: H’0400 ~ H’047F
Area for special functions: H’0000 ~ H’001F
CR for the 1st special module: H’1600 ~ H’1630
CR for the 2nd special module: H’1640 ~ H’1670
CR for the 3rd special module: H’1680 ~ H’16B0
H’03 Reading register bit
CR for the 4th special module: H’16C0 ~ H’16F0
CR for the 5th special module: H’1700 ~ H’1730
CR for the 6th special module: H’1740 ~ H’1670
CR for the 7th special module: H’1780 ~ H’16B0
th
special module: H’17C0 ~ H’17F0
H’05
Writing single datum into bit
device
CR for the 8
bit DO area: H’0500 ~ H’057F
RTU-485 RUN/STOP mode: H’0003
H’06 Writing single datum into register word
Applicable to CR with R/W attribute in the 1
special module
H’0F DO area: H’0500 ~ H’057F
H’10 Writing many data into bit device bit
Applicable to CR with R/W attribute in the 1
special module
st
~ 8th
st
~ 8th
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DVP-PLC Application Manual
Modbus Remote I/O Communication Module RTU-485
6 Application of RTU-485
6.1 Connection between RTU-485 and Master Device
As a standard Modbus slave, RTU-485 is compatible with pther programmable logic controllers which also
comply with Modbus protocol. The example here takes DVP-SV PLC as the master. The PC downloads the
ladder diagram to DVP-SV through RS-232 communication port (COM1). When DVP-SV executes the ladder
diagram program, it will send out Modbus command through RS-485 communication port (COM2) and conduct
remote I/O control on RTU-485. See the figure on the next page for the connectio n between RTU-485 and the
master device:
DVP28SV
RUN
STOP
6.2 Application Example
Example 1
¡ The station No. of RTU-485 is “1”. Write “H’0001” into CR#6 of the 1
M1002
DVP-SV
RS-485
T
P
S
8
0
P
V
D
DI/DO
Slim
S
6
1
P
V
D
5
8
4
U
T
R
COM2
RTU-485
MOV H86 D1120
RST
SET M1120
M1143
Retain communication protocol
D
A
4
0
P
V
D
P
T
4
0
P
V
D
D
4
2
0
0
-
P
P
V
V
D
D
A
T
C
Special
module
st
special module.
Set up communication protocol
9600,7,E,1,ASCII
M0
M0
M1123
M1129
DVP-PLC Application Manual
MOV K300 D1129
SET M1122
MODWR
K1 H1606 H0001
Set up sending request
Set up communication time-out 300ms
Process received data
RST M1123
Recei vin g of data is compl eted.
The flag is reset.
Process communica tion time-out
RST M1129
END
Wr ite H0001 i nto CR#6 of
st
the 1 special module
9
Modbus Remote I/O Communication Module RTU-485
¡ Explanations
1. You have to set up the communication format at the beginning of the program. The communication
format for the master and slave has to be consistent, e.g. you can see the format is 9600, 7, E, 1,
ASCII from this example.
2. After setting up the communication format, you have to set up the communication retention device
M1120 of COM2.
3. After M0 is On, set up the sending request flag, and the master device will send out a request
message to RTU-485 and write H’0001 into CR#6 of the 1
RTU-485.
Example 2
¡ The station No. of RTU-485 is “1”. Set up Y0 of the Slim DI/DO on the right hand side of RTU-485.
M1002
MOV H86
RST M1143
D1120
st
special module on the right hand side of
Set up communicatio n protoco l
9600, 7, E, !, ASCII
M0
M0
SET M1120
MOV
MOV
MOV
MOV
MOV
MOV
MOV
MOV
MOV
MOV
SET M1122
RS D100 K17 D120 K17
K300
H303A D100
H3031 D101
H3035 D102
H3035 D103
H4630 D104
H3046 D105
H4630 D106
HD107
HA
Retain communication protocol
D1129
D36
D108
Set up sending request
Set up communication time-out 300ms
PLC sends out
": "
01 05 05 00 FF 00 F6 CR LF
to RTU-485
10
M1123
When M0 = On, the 17 words in D100 ~ D10 8 will be sen t out.
The 17 words responded by RTU-485 will be stored i n D120 ~ D128 by the m aster.
Process received data
RST M1123
Recei ving of dat a is complete d.
The flag is reset.
DVP-PLC Application Manual
M1129
Modbus Remote I/O Communication Module RTU-485
Process communication time-out
RST M11 29
END
Explanations
1. You have to set up the communication format at the beginning of the program. The communication
format for the master and slave has to be consistent, e.g. you can see the format is 9600, 7, E, 1,
ASCII from thie example.
2. The master PLC sends out data to RTU-485 in ASCII, e.g. the high byte “30” in D100 refers to “0” and
low bytes “3A” refers to the head code “:”.
3. After M0 is On, set up M1 122. At this moment, the master PLC will send the 17 words of dat a in D100
~ D108 to RTU-485 by RS instruction. The data in low words will be sent first. The master PLC will
store the responding message sent by RTU-485 into D120 ~ D128.
7 LED Indicator & Trouble-shooting
There are four LED indicators on RTU-485, which are POWER, RUN, ALARM and RS-485, for displaying the
working status and communication connection status of RTU-485.
7.1 POWER LED
LED status Indication How to correct
Off No power, or the power is abnormal.
Green light On The power of RTU-4 85 is normal. --
Check the power of RTU-485 and see if the
connection is normal.
7.2 RUN LED
LED status Indication How to correct
Off RTU-485 is in STOP status. --
Green light On RTU-485 is in RUN status. --
7.3 ALARM LED
LED status Indication How to correct
Off The power is in low voltage. Check if the power of RTU-485 is normal.
Red light On
Incorrect communication format for
RTU-485
Incorrect communication address for
RTU-485
RTU-485 is not connected to
extension module.
More than 8 extension modules
connected to RTU-485.
The number of points on Slim DI/DO
connected to RTU-485 exceeds the
range.
Check if the communication format for RTU-485
is correct.
Check if the communication address of RTU-485
is valid.
Check if RTU-485 is connected to extension
module normally.
Check and make sure that the number of
extension modules connected to RTU-485 is
less than 8.
Check and make sure the number of input points
on Slim DI/DO connected to RTU-485 is less
than 128, and output points also less than 128.
DVP-PLC Application Manual
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Modbus Remote I/O Communication Module RTU-485
7.4 RS-485 LED
LED status Indication How to correct
Red light flashing
Off
RTU-485 is not communicating with
the master device.
RTU-485 is communicating to the
master device normally.
--
--
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DVP-PLC Application Manual
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