Ebyte E820-AIO User manual

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2
E820-AIO is the analog signal collection product designed by Ebyte.
With RS485 communication network, E820-AIO transmits the analog signal
of scattered field data point via AD transformation to master or control
remote home site via the PC. Built-in watch dog (0.2s reset), the system
won’t be halted easily. E820-AIO analog acquisition module features
measurement data collection, measured data collection, device switch
status collection etc, mainly used for the data collection, controlling and
device display of various measurement and control terminal, suitable for the automation and information
systems in various industries.
Features
Wide working temperature range: working at -40℃～+65℃, suitable for harsh working environment.
Non directional design of input power: This can avoid misconnection and over connection damage,
increasing the reliability.
Modbus protocol: Q&A communication, easy to use and featuring cheap hardware and strong
universal property.
High acquisition accuracy: it’s 0.1%FS.
All aluminum alloy shell: Good EMS performance, compact size, easy installation and good heat
dissipation.
Watch dog: This can conduct the precise time layout. Once any exception occurs, the module will
restart in 0.2s and continue to work as previous parameters.
1. Electrical Parameters
1.1 E820-AIO（II-485-4-20）
N
o
Parameter
Name
Parameter value
Description
1
Size
108 * 75 *37mm
Pressing line interface is not included.
2
Average weight
226g
Pressing line interface is not included.
3
Input signal
type
0—20mA
Analog signal input range.
4
Acquisition
channel
4 channel input
4 channel Single-ended input of analog signal.

3
5
Acquisition rate
Full channel
10Hz
Acquisition rate for analog signal.
6
Interface
RS485：1 * 5 *
3.81 mm
Line pressing
7
Supply voltage
5 ~ 36V DC
Note: The module will be destroyed if the voltage is higher than
36V.
8
Working
current
12V/50mA
5V/90mA，12V/50mA，24V/30mA，36V/20mA(The over 100mA output
current is recommended when the output power is not used).
9
Communicatio
n level
RS485
RS485
10
Communicatio
n address
1-247
1-247 can be configurable, the default is 1.
11
Acquisition
accuracy
0.1%FS
Accuracy of analog signal collection.
12
Baud rate
Default: 9600
It can be configured from 1200~115200.
13
Working
temperature
-40℃～+65℃
Industrial grade.
14
Isolation
protection
3000vDC
Lightening strike, Surge protection.
1.2 Series products
Model Number
Interface
Signal type
Acquisition
accuracy
Analog
channel
Protection
level VDC
Size
E820-AIO
（II-485-4-20）
RS485
0-20mA
0.1%FS
4
3000
82*84.25
1.3 FAQ
No.
Questions
Description
1
Change baud rate
When using the upper computer, users need to close the upper computer first
and reopen after changing the baud rate.
2
Forget the device
address
Users can use 03 command to read FF monitoring.
1.4 Notice
No.
Notice
Description

4
1
Communication
connection
In connecting with other RS485 device, users need to pay attention to the
match of A, B line and add 120R matching resistance.
2
Input voltage
Only DC power supply is available, and the DC input voltage should be
10-28V
The device won’t work when lower than 10V, while the device will be
destroyed when higher than 28V,
3
Output power
supply
The positive and negative directions of output power is same with the input
power. See more details in Pin definition.
4
Analog input
interface
The collection signal is 0-20Ma/0-5V, so user do not input the exceed
nominal measured value, or it may cause damage.
5
Waterproof
The device is not waterproof, please do not get the device wet, or it will be
damaged.

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2. Function Description
2.1 Pin definition
Pin
Definition
Function
Description

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1
DC-IN
Pressing line power input
positive
Power input, range: DC10-28V. 12V, and 24V are
recommended.
2
GND
Pressing line power input
negative
Power supply GND.
3
AGND
Communication common
ground
When communicating with RS485, the DTU won’t be
used, while when communicating with RS232, it will be
grounded.
4
RS485_A
Interface A of RS-485
Interface A of RS-485 connected to Device A.
5
RS485_B
Interface B of RS-485
Interface B of RS-485 connected to Device B.
6
AI1+
Analog signal input channel 1
positive
Input pin of analog signal forms the input with the
GND1 pin.
7
AI1-
Analog signal input channel 1
negative
To be used in pairs with VI1+.
8
AI2+
Analog signal input channel 2
positive
Input pin of analog signal, forms the input with the
GND2 pin.
9
AI2-
Analog signal input channel 2
negative
To be used in pairs with VI2+.
10
AI3+
Analog signal input channel 3
positive
Input pin of analog signal, forms the input with the
GND3 pin.
11
AI3-
Analog signal input channel 3
negative
To be used in pairs with VI3+.
12
AI4+
Analog signal input channel 4
positive
Input pin of analog signal forms the input with the
GND4 pin.
13
AI4-
Analog signal input channel 4
negative
To be used in pairs with VI4+.
14
GND
Power supply output
negative
The negative internal of power supply connected to
pin 2 GND.
15
Vout
Power supply output positive
Power supply output, the voltage is decided by the pin
1(internal connecting to pin 1).
16
reset
reset
Long press to reset the equipment parameters to
factory settings. Reset success L1 and L2 indicator
lights flash once
17
Earthing
pole
Earthing pole

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2.2 Connection method
2.2.1 RS485 connection method
3. Register configuration table
3.1 ModBus address table
40001—40012、40017—40028、40042—40049 is not used in this device.
ModBus register address table
Address
Byte
variable names
Type
Description
30013
2
AI4 input
Read only
Unit 0.001mA/0.001V
30014
2
AI3 input
Read only
30015
2
AI2 input
Read only
30016
2
AI1 input
Read only
40029
2
reference voltage for
channel 1
Read/write
Default 2400，Max. 3300，Min 2000，Unit
0.001V
40030
2
reference voltage for
channel 2
Read/write
40031
2
reference voltage for
channel 3
Read/write
40032
2
reference voltage for
channel 4
Read/write
40033
2
ModBus address
Read/write
1-250（0xff is the monitoring address）

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3.2 Baud rate code table
Baud rate code table
0
1200
1
2400
2
4800
3（default）
9600
4
19200
5
38400
6
57600
7
1152200
3.3 Parity bit code table
Parity bit code table
0（default）
No parity
1
Even parity
2
Odd parity
40034
2
Baud rate
Read/write
see more in baud rate table
40035
2
parity bit
Read/write
see more in parity bit table
40036
2
Lower limit register
Read/write
0-65535（Lower limit register must be less
than the Upper limit register . After the
configuration, channel 1-4 will be the
range of upper and lower limits.
40037
2
Upper limit register
Read/write
40038
2
Conversion value for
channel 1
Read only
The original data value transformed by
the analog quantity of channel 1
40039
2
Conversion value for
channel 2
Read only
The original data value transformed by
the analog quantity of channel 2
40040
2
Conversion value for
channel 3
Read only
The original data value transformed by
the analog quantity of channel 3
40041
2
Conversion value for
channel 3
Read only
The original data value transformed by
the analog quantity of channel 4

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4. Instruction format
4.1 Input“03”to read the command of single register
Users input”03” to read the command of register value. Below is the command to read the value of baud rate:
01
03
00 21
00 01
D4 00
ModBus Address
To read command
To read the address
of register
To read the length of
register
CRC parity code
Send above command via the serial assistant to module, then below value will be returned:
01
03
02
00 03
F8 48
ModBus
Address
To read command
To read the return
bytes
The value of 40034 is 3，
which means the baud
rate is 9600，see more
details in baud rate value
table.
CRC parity code
Note: With the known baud rate, to use FF monitoring address can read the unremembered register value,
Such as, send FF 03 00 21 00 01 c1de to read the address of device. CRC parity check code can be calculated by
CRC16 system, the assistant software can be downloaded in official website.
4.2 Input“03”to read the command of multiple registers
Users input”03” to read the command of register value. Below is the command to read the address of 40034
to 40036:
01
03
00 21
00 03
55 C1
ModBus
address
To read command
To read the address of
register
To read the length of
register
CRC parity code
Send above command via the serial assistant to module, then below value will be returned:
01
03
06
00 03
00 00
00 00
65 75
ModBus
address
To read
command
To read the
return
bytes
The value of
40034 is 3，
which means the
baud rate is
9600，see more
details in baud
The value of
40035 is 0, the
parity bit of
device is no
parity, see more
details in parity
The value of
40036 is 0
CRC parity
code

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rate value table.
check code
table.
4.3 Input “06” to write the command of register
Input “06”to write single command, below is the command to change the baud rate as 19200：
01
06
00 21
00 04
D8 03
ModBus
address
To write
command
Write in 40034 register
The write value of 40034
is 4, the corresponding
baud rate is 19200, see
more details in baud rate
table
CRC parity code
If the revision is successful, module will return 01 06 00 21 00 04 d803.
4.4 Factory default value
Device address
Baud rate
Voltage for
reference
Parity check code
40033 address is 1
9600，that is, 40034
address is 3
2400
No parity check：40035 address is 0
5. Software instructions
5.1.MoBusCRC16 calculator
Ebyte will provide the MoBusCRC16 calculator for your convenience, which will automatically add the
CRC16 parity check code after the input data. Please pay attention to the format, if it’s less than f, then should
add 0 in the front, such as 01, 06, and each digit should followed by a blank.
5.2.E820 testing software
In the upper monitor software, the start address of register is set in the address column, the length should
be from start address to end address. For example, address is 1, which means to read from 40001. The length
of 49 should read 49 registers from 40001-40049. Analog quantity input(1,2,3,4) should be the real current
value input by the current channel. Channel (1,2,3,4) conversion value shows that the analog signal of current
channel converted to the original value after collection.