iNDTelect i-chAMP RPG 1.0-1
2-channel IEPE charge amplier with RS485 interface
iNDTact GmbH
©
2015
Date: February 10, 2015
1 Summary
1.2 Applications
ˆ Amplication / buering of sensor signals
1.1 Features
ˆ Preamplication for ADC
ˆ Low noise signal conditioning
Type
Channels
Gain
...
...
...
Bandwidth
lower corner freq.
upper corner freq.
IEPE current
IEPE voltage
Supply voltage
Supply current
...
...
...
...
...
...
...
IEPE charge amplier
2
Variable
-56dB to 0dB
0,0016 - 1mV/pC
11kHz
22mHz
11kHz
4mA
2-24V
5V
40mA
ˆ Active ltering
1.3 Description
The i-chAMP RPG 1.0-1 is a charge amplier according to the IEPE principle with RS485 interface. It
oers two congurable channels. The gain can be
set independently for each channel. The amplier
i-chAMP RPG 1.0-1 is designed specically for the
iNDTact sensors and allows easy and exible signal
conditioning.
1
Contents
i-chAMP RPG 1.0-1
Contents
1 Summary
1
2 Absolute Maximum Ratings
3
3 Electrical Characteristics
3
4 Pin Conguration
3
5 Typical Performance Characteristics
4
6 Block Diagram
5
1.1
1.2
1.3
4.1
4.2
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8-pole Lumberg 0315-2 08-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7 Serial Port Protocol
7.1
7.2
7.3
7.4
MODBUS Addressing rules . . .
MODBUS ASCII Message Frame
LRC Checking . . . . . . . . . .
i-chAMP RPG 1.0-1 functions . .
Error codes . . . . . . . . . . . .
Set new MODBUS slave address
Unlock MODBUS slave address .
Restart device . . . . . . . . . . .
Set test mode on/o . . . . . . .
Get temperature . . . . . . . . .
Set IEPE gain value . . . . . . .
Get IEPE gain value . . . . . . .
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1
1
1
3
3
5
6
6
6
7
7
8
9
10
11
12
13
14
8 Revision History
15
9 Disclaimer Of Warranty
15
2
4 PIN CONFIGURATION
i-chAMP RPG 1.0-1
2 Absolute Maximum Ratings
Vdd
RS485A, RS485B
IEPE CH1, IEPE CH2
ESD for all pins
..........
..........
..........
..........
Storage temperature
Operating temperature
0V to 5,5V
-7V to 12V
0V to 27V
air 15kV
contact 8kV
(IEC61000-4-2)
..........
..........
-40°C to 150°C
-40°C to 85°C
3 Electrical Characteristics
Parameter
Supply voltage Vdd
Supply current Idd
Power consumption
IEPE Oset @ +20°C
... @ -20°C
... @ +55°C
IEPE signal voltage
Min
4,5
9,0
5,0
14,0
2
Typ
5,0
40
200
10,5
6,5
15,5
Max
5,5
12,0
8,0
17,0
24
Unit
V
mA
mW
V
V
V
V
4 Pin Conguration
4.1 8-pole Lumberg 0315-2 08-1
Seen from the solder side.
Pin
Name
1
2
3
4
5
6
7
8
IEPE CH1
RS485 B
IEPE CH2
IEPE GND
DGND
Vdd
NC
RS485 A
4.2 Pin Description
Pin
Name
1
IEPE CH1
2
RS485 B
3
IEPE CH2
4
5
6
7
8
IEPE GND
DGND
Vdd
NC
RS485 A
Description
Positive IEPE line of channel number one. This line must be supplied with
the IEPE current for IEPE functionality.
Inverting serial data line of the RS485 interface.
Positive IEPE line of channel number two. This line must be supplied with
the IEPE current for IEPE functionality.
Common negative IEPE line for both IEPE channels.
Digital ground.
Digital supply voltage.
Not connected.
Noninverting serial data line of the RS485 interface.
3
5 TYPICAL PERFORMANCE CHARACTERISTICS
i-chAMP RPG 1.0-1
5 Typical Performance Characteristics
Normalized transfer vs. frequency
Normalized transfer vs. frequency
3
T r a n s fe r fu n c tio n n o r m a liz e d
T r a n s fe r fu n c tio n n o r m a liz e d
0
1 ,0
0 ,8
A m p litu d e [A /A
A m p litu d e [d B ]
0
]
-3
-6
-9
-1 2
0 ,6
0 ,4
-1 5
0 ,2
-1 8
0 ,0
1 0 m
1 0 0 m
1
1 0
1 0 0
1 k
1 0 k
1 0 0 k
1 0 m
1 0 0 m
1
1 0
F re q u e n c y [H z ]
Gain dependent transfer vs. frequency
G a in
G a in
G a in
G a in
G a in
1 m
1 k
1 0 k
1 0 0 k
= 0 x
= 0 x
= 0 x
= 0 x
= 0 x
Gain dependent transfer vs. frequency
0 0
0 1
G a in
G a in
G a in
G a in
G a in
1 0 0 µ
0 2
0 3
0 4
= 0 x
= 0 x
= 0 x
= 0 x
= 0 x
0 5
0 6
0 7
0 8
0 9
8 0 µ
T ra n s fe r [V /p C ]
8 0 0 µ
T ra n s fe r [V /p C ]
1 0 0
F re q u e n c y [H z ]
6 0 0 µ
4 0 0 µ
2 0 0 µ
6 0 µ
4 0 µ
0
1 0 0 m
2 0 µ
1
1 0
1 0 0
1 k
1 0 k
1 0 0 k
0
1 0 0 m
1 M
1
1 0
1 0 0
F re q u e n c y [H z ]
1 k
1 0 k
1 0 0 k
1 M
F re q u e n c y [H z ]
Gain dependent transfer vs. frequency
G a in
G a in
G a in
G a in
G a in
1 0 ,0 µ
= 0 x
= 0 x
= 0 x
= 0 x
= 0 x
Gain variation vs. frequency
1 0
0 A
0 B
0 C
0 D
5
0 E
G a in v a r ia tio n [% ]
T ra n s fe r [V /p C ]
8 ,0 µ
6 ,0 µ
4 ,0 µ
2 ,0 µ
0 ,0
1 0 0 m
0
-5
-1 0
M a x im
A v e ra
A v e ra
M a x im
1
-1 5
1 0
1 0 0
1 k
1 0 k
1 0 0 k
-2 0
1 0 0 m
1 M
F re q u e n c y [H z ]
1
1 0
1 0 0
F re q u e n c y [H z ]
4
u m
g e p
g e n
u m
1 k
p o
o s
e g
n e
s itiv v a r ia tio n
itiv v a r ia tio n
a tiv v a r ia tio n
g a tiv v a r ia tio n
1 0 k
1 0 0 k
7 SERIAL PORT PROTOCOL
i-chAMP RPG 1.0-1
6 Block Diagram
i‐chAMP RPG
IEPE
interface
IEPE GND
Electronic decoupling layer
RS485
interface
RS485 A
RS485 B
Control logic
DGND
7 Serial Port Protocol
The i-chAMP RPG 1.0-1 has a RS485 interface to adjust gain settings, read the chassis temperatur etc. The
physical interface specication are as follows:
Bits per second
Data bits
Parity type
Stop bits
Flow control
:
:
:
:
:
9600 Baud
7
Even
1
None
The physical interface specications as well as the communication protocol correspond to the MODBUS over
serial line specications version 1.02 as specied in the following online documentation:
http://modbus.org/docs/Modbus_over_serial_line_V1_02.pdf
More detailed information can be found in the MODBUS Application Protocol Specication V1.1b3:
http://modbus.org/docs/Modbus_Application_Protocol_V1_1b3.pdf
The only mode supported is the ASCII
are those found in this document.
Transmission Mode.
And the only request functions supported
In ASCII Transmission Mode every byte is send as its two character long hexadecimal representation. Example : The byte 0x5B is encoded as two characters : 0x35 and 0x42 ( 0x35 ="5", and 0x42 ="B" in
ASCII).
5
7 SERIAL PORT PROTOCOL
i-chAMP RPG 1.0-1
7.1 MODBUS Addressing rules
0
Broadcast address
From 1 to 247
Slave individual addresses
From 248 to 255
Reserved
The MODBUS addressing space comprises 256 dierent addresses. The Address 0 is reserved as the broadcast
address. All slave nodes must recognise the broadcast address. The MODBUS Master node has no specic
address, only the slave nodes must have an address. This address must be unique on a MODBUS serial bus.
7.2 MODBUS ASCII Message Frame
A MODBUS message is placed by the transmitting device into a frame that has a known beginning and
ending point. This allows devices that receive a new frame to begin at the start of the message, and to know
when the message is completed.
In ASCII mode, a message is delimited by specic characters as Start-of-frames and End-of-frames. A
message must start with a `colon' ( : ) character (ASCII 3A hex), and end with a `carriage return line
feed' (CRLF) pair (ASCII 0D and 0A hex).
The allowable characters transmitted for all other elds are hexadecimal 09, AF (ASCII coded).
Start
1 Chars
:
Address
2 Chars
Function
2 Chars
Data
0 bis 2x252 Chars
LRC
2 Chars
End
2 Chars
CR LF
7.3 LRC Checking
In ASCII mode, messages include an errorchecking eld that is based on a Longitudinal Redundancy
Checking (LRC) calculation that is performed on the message contents, exclusive of the beginning `colon'
and terminating CRLF pair characters. It is applied regardless of any parity checking method used for the
individual characters of the message.
The LRC eld is one byte, containing an 8bit binary value. The LRC value is calculated by the device that
emits, which appends the LRC to the message. The device that receives calculates an LRC during receipt of
the message, and compares the calculated value to the actual value it received in the LRC eld. If the two
values are not equal, an error results.
The LRC is calculated by adding together successive 8bit bytes of the message, discarding any carries, and
then two's complementing the result. It is performed on the bytes of the message, before the encoding of
each byte in the two ASCII characters corresponding to the hexadecimal representation of each nibble. The
computation does not include the 'colon' character that begins the message, and does not include the CRLF
pair at the end of the message. The resulting LRC is ASCII encoded into two bytes and placed at the end
of the ASCII mode frame before the CRLF.
6
7 SERIAL PORT PROTOCOL
i-chAMP RPG 1.0-1
7.4 i-chAMP RPG 1.0-1 functions
Function name
Function code
Unlock Address
0x48
New Address
0x41
Description
Unlock MODBUS slave address. You have to execute this
function immediatly before executing New Address
function.
Set new MODBUS slave address.
CAUTION! Hardware damage can be
induced by improper use of this function!
Reset
Set Testmode
Get Temperature
Set Gain
Get Gain
0x42
0x43
0x44
0x64
0x65
Restart device.
Set test mode on/o. (for internal use)
Get temperature.
Set IEPE gain value.
Get IEPE gain value.
Error codes
The following error codes can be returned from the device:
Code
Name
01
ILLEGAL FUNCTION
03
ILLEGAL DATA VALUE
04
SERVER DEVICE FAILURE
Meaning
The function code received in the query is not an allowable
action for the server.
A value contained in the query data eld is not an
allowable value for server. This indicates a fault in the
structure of the remainder of a complex request, such as
that the implied length is incorrect or the data value is out
of expected range.
An unrecoverable error occurred while the server was
attempting to perform the requested action.
7
7 SERIAL PORT PROTOCOL
i-chAMP RPG 1.0-1
Set new MODBUS slave address
Warning
In case of improper usage of this function the addressed device as well as other
devices in the transmission line can be set in a nonreversible faulty state!
Description
This function requests a MODBUS slave address change. The slave address is locked in normal operation.
Before you can request a change you have to unlock the address. See Unlock Address function for more
information.
It is recommended to check whether the new target address already exists in the system before it is assigned.
It can be checked e.g. by trying to read the temperature from the new address. If you get an answer the
target address is already in use and you must not assign this address to a second device.
Request
Parameter
Slave address
Function code
Data block
Size
Valid data
2 Chars
2 Chars
2 Chars
0x01 to 0xF7
0x41
0x01 to 0xF7
Description
Slave address. No broadcasting support.
New slave address to assign.
CAUTION: Do not assign a slave
address that already exists on this
serial line! It will be impossible to
seperate these devices without
physically unplugging all devices
but one off the transmission line.
Response
Parameter
Slave address
Function code
Data block
Size
Data
Description
2 Chars
2 Chars
2 Chars
0x01 to 0xF7
0x41
0x01 to 0xF7
Old slave address.
New slave address assigned.
Error
Parameter
Slave address
Error code
Data block
Size
Data
Description
2 Chars
2 Chars
2 Chars
0x01 to 0xF7
0xC1
0x01 to 0x04
Slave address.
Function code + 0x80
Error Code
0x04 SERVER_DEVICE_FAILURE if address
is locked.
Example
Parameter
Slave address
Function code
Data block
Complete request
Size
Data
2 Chars 0x01
2 Chars 0x41
2 Chars 0x02
:014102BC\r\n
Description
Slave address.
New slave address to assign.
Complete request with start of frame, LRC and
end of frame
8
7 SERIAL PORT PROTOCOL
i-chAMP RPG 1.0-1
Unlock MODBUS slave address
Description
Unlocks the MODBUS slave address of the device. In normal operation mode the slave address of the device
is locked to prevent it from being accidentally changed. If you want to change the address you have to unlock
it. After successfully requesting this function the address will be unlocked for one function request. If this
one request is the Set Address function, it will succeed. Any other request will relock the address.
Request
Parameter
Slave address
Function code
Data block
Size
Valid data
2 Chars
2 Chars
0x01 to 0xF7
0x48
Size
Data
2 Chars
2 Chars
0x01 to 0xF7
0x48
Description
Slave address. No broadcasting support.
No data.
Response
Parameter
Slave address
Function code
Data block
Description
Slave address.
No data.
Error
Parameter
Slave address
Error code
Data block
Size
Data
Description
2 Chars
2 Chars
2 Chars
0x01 to 0xF7
0xC8
0x01 to 0x04
Slave address.
Function code + 0x80
Error Code
Example
Parameter
Slave address
Function code
Data block
Complete request
Size
Data
2 Chars 0x01
2 Chars 0x48
:0148B7\r\n
Description
Slave address.
No data.
Complete request with start of frame, LRC and
end of frame
9
7 SERIAL PORT PROTOCOL
i-chAMP RPG 1.0-1
Restart device
Description
Restarts the device (Softreset).
Request
Parameter
Slave address
Function code
Data block
Size
Valid data
2 Chars
2 Chars
0x00 to 0xF7
0x42
Size
Data
2 Chars
2 Chars
0x01 to 0xF7
0x42
Description
Broadcast or specic slave address.
No data.
Response
Parameter
Slave address
Function code
Data block
Description
Slave address.
No data.
Error
Parameter
Slave address
Error code
Data block
Size
Data
Description
2 Chars
2 Chars
2 Chars
0x01 to 0xF7
0xC2
0x01 to 0x04
Slave address.
Function code + 0x80
Error Code
Example
Parameter
Slave address
Function code
Data block
Complete request
Size
Data
2 Chars 0x01
2 Chars 0x42
:0142BD\r\n
Description
Slave address.
No data.
Complete request with start of frame, LRC and
end of frame
10
7 SERIAL PORT PROTOCOL
i-chAMP RPG 1.0-1
Set test mode on/o
Description
Sets the testmode on or o. In testmode the device will cycle continuously through all available congurations.
Normal operation is not possible with testmode on.
Request
Parameter
Slave address
Function code
Data block
Size
Valid data
2 Chars
2 Chars
2 Chars
0x00 to 0xF7
0x43
0x00 or 0x01
Size
Data
2 Chars
2 Chars
2 Chars
0x01 to 0xF7
0x43
0x00 or 0x01
Description
Broadcast or specic slave address.
0x00 ... Testmode OFF
0x01 ... Testmode ON
Response
Parameter
Slave address
Function code
Data block
Description
Slave address.
0x00 ... Testmode OFF
0x01 ... Testmode ON
Error
Parameter
Slave address
Error code
Data block
Size
Data
Description
2 Chars
2 Chars
2 Chars
0x01 to 0xF7
0xC3
0x01 to 0x04
Slave address.
Function code + 0x80
Error Code
Example
Parameter
Slave address
Function code
Data block
Complete request
Size
Data
2 Chars 0x01
2 Chars 0x43
2 Chars 0x00
:014300BC\r\n
Description
Slave address.
Testmode OFF
Complete request with start of frame, LRC and
end of frame
11
7 SERIAL PORT PROTOCOL
i-chAMP RPG 1.0-1
Get temperature
Description
Requests a temperature reading.
Request
Parameter
Slave address
Function code
Data block
Size
Valid data
2 Chars
2 Chars
0x01 to 0xF7
0x44
Description
Slave address. No broadcasting support.
No data.
Response
Parameter
Slave address
Function code
Data block
Size
Data
Description
2 Chars
2 Chars
4 Chars
0x01 to 0xF7
0x44
0x0000 to 0x00FF
Slave address.
Char 1+2 (1. Byte): Always null.
Char 3+4 (2. Byte): Temperatur in °C to read
as 8bit signed integer.
Error
Parameter
Slave address
Error code
Data block
Size
Data
Description
2 Chars
2 Chars
2 Chars
0x01 to 0xF7
0xC4
0x01 to 0x04
Slave address.
Function code + 0x80
Error Code
Example
Parameter
Slave address
Function code
Data block
Complete request
Size
Data
2 Chars 0x01
2 Chars 0x44
:0144BB\r\n
Description
Slave address.
No data.
Complete request with start of frame, LRC and
end of frame
12
7 SERIAL PORT PROTOCOL
i-chAMP RPG 1.0-1
Set IEPE gain value
Description
Sets the gain of the IEPE amplier. See Typical Performance Characteristics for more details on the specic
gain settings.
Request
Parameter
Slave address
Function code
Data block
Size
Valid data
2 Chars
2 Chars
2 Chars
0x00 to 0xF7
0x64
0x00 to 0x0E
Description
Broadcast or specic slave address.
Gain setting parameter.
0x00 ... 0dB ... 1mV/pC
0x01 ... -4dB
0x02 ... -8dB
0x03 ... -12dB
..
.
0x05 ... -20dB ... 0,1mV/pC
..
.
0x0A ... -40dB ... 0,01mV/pC
..
.
0x0E ... -56dB
Response
Parameter
Slave address
Function code
Data block
Size
Data
Description
2 Chars
2 Chars
2 Chars
0x01 to 0xF7
0x64
0x00 to 0x0E
Slave address.
Gain setting parameter.
Error
Parameter
Slave address
Error code
Data block
Size
Data
Description
2 Chars
2 Chars
2 Chars
0x01 to 0xF7
0xE4
0x01 to 0x04
Slave address.
Function code + 0x80
Error Code
Example
Parameter
Slave address
Function code
Data block
Complete request
Size
Data
2 Chars 0x01
2 Chars 0x64
2 Chars 0x00
:0164009B\r\n
Description
Slave address.
Gain setting parameter.
Complete request with start of frame, LRC and
end of frame
13
7 SERIAL PORT PROTOCOL
i-chAMP RPG 1.0-1
Get IEPE gain value
Description
Gets the actual gain of the IEPE amplier. See Typical Performance Characteristics for more details on the
specic gain settings.
Request
Parameter
Slave address
Function code
Data block
Size
Valid data
2 Chars
2 Chars
0x01 to 0xF7
0x65
Size
Data
2 Chars
2 Chars
2 Chars
0x01 to 0xF7
0x65
0x00 to 0x0E
Description
Slave address. No broadcasting support.
No data.
Response
Parameter
Slave address
Function code
Data block
Description
Old slave address.
Actual gain settings parameter.
Error
Parameter
Slave address
Error code
Data block
Size
Data
Description
2 Chars
2 Chars
2 Chars
0x01 to 0xF7
0xE5
0x01 to 0x04
Slave address.
Function code + 0x80
Error Code
Example
Parameter
Slave address
Function code
Data block
Complete request
Size
Data
2 Chars 0x01
2 Chars 0x65
:01659A\r\n
Description
Slave address.
No data.
Complete request with start of frame, LRC and
end of frame
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9 DISCLAIMER OF WARRANTY
i-chAMP RPG 1.0-1
8 Revision History
Revision
Date
Change
Description
A
02/15
Document created.
9 Disclaimer Of Warranty
This is an advanced prototype. It is designed for test purposes only. Any use of the i-chAMP RPG 1.0-1 other
than for the purpose intended excludes iNDTact GmbH from any possible liability.
15