1. Introduction
MB2HAL is a generic userspace HAL component to communicate with one or more Modbus devices. So far, there are two options to comunicate with a Modbus device:
-
One option is to create a HAL component as a driver see VFD Modbus.
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Another option is to use Classic Ladder which has Modbus built in see ClassicLadder.
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Now there is a third option that consists of a "generic" driver configured by text file, this is called MB2HAL. Why MB2HAL ? Consider using Mb2hal if:
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You have to write a new driver and you don’t know anything about programming.
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You need to use Classic Ladder "only" to manage the Modbus connections.
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You have to discover and configure first time the Modbus transactions. Mb2hal have debug levels to facilitate the low level protocol debug.
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You have more than one device to connect. Mb2hal is very efficient managing multiple devices, transactions and links. Currently i am monitoring two axis drivers using a Rs232 port, a VFD driver using another Rs232 port, and a remote I/O using TCP/IP.
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You want a protocol to connect your Arduino to HAL. Look the included sample configuration file, sketch and library for Arduino Modbus.
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2. Usage
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Create a config file from the example below
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Set component name (optional)
Set
HAL_MODULE_NAME=mymodule
(defaultHAL_MODULE_NAME=mb2hal
) -
Load the modbus HAL userspace component
-
Default component name:
loadusr -W mb2hal config=config_file.ini
-
Custom component name:
loadusr -Wn mymodule mb2hal config=config_file.ini
-
3. Options
3.1. Init Section
[MB2HAL_INIT]
Value | Type | Required | Description |
---|---|---|---|
|
Integer |
No |
Debug level of init and INI file parsing. 0 = silent |
|
String |
No |
HAL module (component) name. Defaults to "mb2hal". |
|
Float |
No |
Insert a delay of "FLOAT seconds" between transactions in order to not to have a lot of logging
and facilitate the debugging.
Useful when using |
|
Integer |
Yes |
The number of total Modbus transactions. There is no maximum. |
3.2. Transaction Sections
One transaction section is required per transaction, starting at [TRANSACTION_00]
and counting up sequentially.
If there is a new link (not transaction), you must provide the REQUIRED parameters 1st time.
Warning: Any OPTIONAL parameter not specified are copied from the previous transaction.
Value | Type | Required | Description |
---|---|---|---|
|
String |
Yes |
You must specify either a "serial" or "tcp" link for the first transaction. Later transactions will use the previous transaction link if not specified. |
|
IP address |
If |
The Modbus slave device IP address. Ignored if |
|
Integer |
No |
The Modbus slave device TCP port. Defaults to 502. Ignored if |
|
String |
If |
The serial port. For example "/dev/ttyS0". Ignored if |
|
Integer |
If |
The baud rate. Ignored if |
|
Integer |
If |
Data bits. One of 5,6,7,8. Ignored if |
|
String |
If |
Data parity. One of: even, odd, none. Ignored if |
|
Integer |
If |
Stop bits. One of 1, 2. Ignored if |
|
Integer |
If |
Serial port delay in ms between transactions of this section only.
In ms. Defaults to 0. Ignored if |
|
Integer |
Yes |
Modbus slave number. |
|
Integer |
Yes |
The first element address. |
|
Integer |
Unless |
The number of elements. It is an error to specify both
|
|
List |
Unless |
A list of element names.
These names will be used for the pin names, e.g. mb2hal.plcin.cycle_start.
NOTE: there must be no white space characters in the list.
Example: |
|
String |
Yes |
Modbus transaction function code (see specifications): • fnct_01_read_coils |
|
Integer |
No |
Response timeout for this transaction. In ms. Defaults to 500 ms. This is how much to wait for 1st byte before raise an error. |
|
Integer |
No |
Byte timeout for this transaction. In ms. Defaults to 500 ms. This is how much to wait from byte to byte before raise an error. |
|
String |
No |
Instead of giving the transaction number, use a name. Example: |
|
Float |
No |
Maximum update rate in Hz. Defaults to 0.0 (0.0 = as soon as available = infinit).
NOTE: This is a maximum rate and the actual rate may be lower. If you want to calculate it in ms use (1000 / required_ms).
Example: 100 ms = |
|
String |
No |
Debug level for this transaction only. See |
3.3. Error codes
While debugging transactions, note the returned "ret[]
" value correspond to:
Modbus protocol exceptions:
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0x01 - ILLEGAL_FUNCTION - the FUNCTION code received in the query is not allowed or invalid.
-
0x02 - ILLEGAL_DATA_ADDRESS - the DATA ADDRESS received in the query is not an allowable address for the slave or is invalid.
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0x03 - ILLEGAL_DATA_VALUE - a VALUE contained in the data query field is not an allowable value or is invalid.
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0x04 - SLAVE_DEVICE_FAILURE - SLAVE (or MASTER) device unrecoverable FAILURE while attempting to perform the requested action.
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0x04 - SERVER_FAILURE - (see above).
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0x05 - ACKNOWLEDGE - This response is returned to PREVENT A TIMEOUT in the master. A long duration of time is required to process the request in the slave.
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0x06 - SLAVE_DEVICE_BUSY - The slave (or server) is BUSY. Retrasmit the request later.
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0x06 - SERVER_BUSY - (see above).
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0x07 - NEGATIVE_ACKNOWLEDGE - Unsuccessful programming request using function code 13 or 14.
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0x08 - MEMORY_PARITY_ERROR - SLAVE parity error in MEMORY.
-
0x0A (-10) - GATEWAY_PROBLEM_PATH - Gateway path(s) not available.
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0x0B (-11) - GATEWAY_PROBLEM_TARGET - The target device failed to repond (generated by master, not slave).
Program or connection:
-
0x0C (-12) - COMM_TIME_OUT
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0x0D (-13) - PORT_SOCKET_FAILURE
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0x0E (-14) - SELECT_FAILURE
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0x0F (-15) - TOO_MANY_DATAS
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0x10 (-16) - INVALID_CRC
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0x11 (-17) - INVALID_EXCEPTION_CODE
4. Example config file
Click here to download.
#This .INI file is also the HELP, MANUAL and HOW-TO file for mb2hal. #Load the modbus HAL userspace module as the examples below, #change to match your own HAL_MODULE_NAME and .ini file name #Using HAL_MODULE_NAME=mb2hal or nothing (default): loadusr -W mb2hal config=config_file.ini #Using HAL_MODULE_NAME=mymodule: loadusr -Wn mymodule mb2hal config=config_file.ini # ++++++++++++++++++++++++ # Common section # ++++++++++++++++++++++++ [MB2HAL_INIT] #OPTIONAL: Debug level of init and INI file parsing. # 0 = silent. # 1 = error messages (default). # 2 = OK confirmation messages. # 3 = debugging messages. # 4 = maximum debugging messages (only in transactions). INIT_DEBUG=3 #OPTIONAL: HAL module (component) name. Defaults to "mb2hal". HAL_MODULE_NAME=mb2hal #OPTIONAL: Insert a delay of "FLOAT seconds" between transactions in order #to not to have a lot of logging and facilitate the debugging. #Useful when using DEBUG=3 (NOT INIT_DEBUG=3) #It affects ALL transactions. #Use "0.0" for normal activity. SLOWDOWN=0.0 #REQUIRED: The number of total Modbus transactions. There is no maximum. TOTAL_TRANSACTIONS=7 # ++++++++++++++++++++++++ # Transactions # ++++++++++++++++++++++++ #One transaction section is required per transaction, starting at 00 and counting up sequentially. #If there is a new link (not transaction), you must provide the REQUIRED parameters 1st time. #Warning: Any OPTIONAL parameter not specified are copied from the previous transaction. [TRANSACTION_00] #REQUIRED: You must specify either a "serial" or "tcp" link for the first transaction. #Later transaction will use the previous transaction link if not specified. LINK_TYPE=tcp #if LINK_TYPE=tcp then REQUIRED (only 1st time): The Modbus slave device ip address. #if LINK_TYPE=serial then IGNORED TCP_IP=192.168.2.10 #if LINK_TYPE=tcp then OPTIONAL. #if LINK_TYPE=serial then IGNORED #The Modbus slave device tcp port. Defaults to 502. TCP_PORT=502 #if LINK_TYPE=serial then REQUIRED (only 1st time). #if LINK_TYPE=tcp then IGNORED #The serial port. SERIAL_PORT=/dev/ttyS0 #if LINK_TYPE=serial then REQUIRED (only 1st time). #if LINK_TYPE=tcp then IGNORED #The baud rate. SERIAL_BAUD=115200 #if LINK_TYPE=serial then REQUIRED (only 1st time). #if LINK_TYPE=tcp then IGNORED #Data bits. One of 5,6,7,8. SERIAL_BITS=8 #if LINK_TYPE=serial then REQUIRED (only 1st time). #if LINK_TYPE=tcp then IGNORED #Data parity. One of: even, odd, none. SERIAL_PARITY=none #if LINK_TYPE=serial then REQUIRED (only 1st time). #if LINK_TYPE=tcp then IGNORED #Stop bits. One of 1, 2. SERIAL_STOP=2 #if LINK_TYPE=serial then OPTIONAL: #if LINK_TYPE=tcp then IGNORED #Serial port delay between for this transaction only. #In ms. Defaults to 0. SERIAL_DELAY_MS=10 #REQUIRED (only 1st time). #Modbus slave number. MB_SLAVE_ID=1 #REQUIRED: The first element address. FIRST_ELEMENT=0 #REQUIRED unless PIN_NAMES is specified: The number of elements. #It is an error to specify both NELEMENTS and PIN_NAMES #The pin names will be sequential numbers e.g mb2hal.plcin.01 #NELEMENTS=4 #REQUIRED unless NELEMENTS is specified: A list of element names. #these names will be used for the pin names, e.g mb2hal.plcin.cycle_start #NOTE: there must be no white space characters in the list PIN_NAMES=cycle_start,stop,feed_hold #REQUIRED: Modbus transaction function code (see www.modbus.org specifications). # fnct_02_read_discrete_inputs (02 = 0x02) # fnct_03_read_holding_registers (03 = 0x03) # fnct_04_read_input_registers (04 = 0x04) # fnct_06_write_single_register (06 = 0x06) # fnct_15_write_multiple_coils (15 = 0x0F) # fnct_16_write_multiple_registers (16 = 0x10) # # Created pins: # fnct_02_read_discrete_inputs: # mb2hal.m.n (bit out) # fnct_03_read_holding_registers: # fnct_04_read_input_registers: # mb2hal.m.n.float (float out) # mb2hal.m.n.int (s32 out) # fnct_06_write_single_register: # mb2hal.m.n (float in) # NELEMENTS needs to be 1 or PIN_NAMES must contain just one name. # fnct_15_write_multiple_coils: # mb2hal.m.n (bit in) # fnct_16_write_multiple_registers: # mb2hal.m.n (float in) # # m = HAL_TX_NAME or transaction number if not set, n = element number (NELEMENTS) or name from PIN_NAMES # Example: mb2hal.00.01.<type> (transaction=00, second register=01 (00 is the first one)) # mb2hal.TxName.01.<type> (HAL_TX_NAME=TxName, second register=01 (00 is the first one)) MB_TX_CODE=fnct_03_read_holding_registers #OPTIONAL: Response timeout for this transaction. In INTEGER ms. Defaults to 500 ms. #This is how much to wait for 1st byte before raise an error. MB_RESPONSE_TIMEOUT_MS=500 #OPTIONAL: Byte timeout for this transaction. In INTEGER ms. Defaults to 500 ms. #This is how much to wait from byte to byte before raise an error. MB_BYTE_TIMEOUT_MS=500 #OPTIONAL: Instead of giving the transaction number, use a name. #Example: mb2hal.00.01 could become mb2hal.plcin.01 #The name must not exceed 28 characters. #NOTE: when using names be careful that you dont end up with two transactions #using the same name. HAL_TX_NAME=remoteIOcfg #OPTIONAL: Maximum update rate in HZ. Defaults to 0.0 (0.0 = as soon as available = infinit). #NOTE: This is a maximum rate and the actual rate may be lower. #If you want to calculate it in ms use (1000 / required_ms). #Example: 100 ms = MAX_UPDATE_RATE=10.0, because 1000.0 ms / 100.0 ms = 10.0 Hz MAX_UPDATE_RATE=0.0 #OPTIONAL: Debug level for this transaction only. #See INIT_DEBUG parameter above. DEBUG=1 #While DEBUGGING transactions note the returned "ret[]" value correspond to: #/* Modbus protocol exceptions */ #ILLEGAL_FUNCTION -0x01 the FUNCTION code received in the query is not allowed or invalid. #ILLEGAL_DATA_ADDRESS -0x02 the DATA ADDRESS received in the query is not an allowable address for the slave or is invalid. #ILLEGAL_DATA_VALUE -0x03 a VALUE contained in the data query field is not an allowable value or is invalid. #SLAVE_DEVICE_FAILURE -0x04 SLAVE (or MASTER) device unrecoverable FAILURE while attempting to perform the requested action. #SERVER_FAILURE -0x04 (see above). #ACKNOWLEDGE -0x05 This response is returned to PREVENT A TIMEOUT in the master. # A long duration of time is required to process the request in the slave. #SLAVE_DEVICE_BUSY -0x06 The slave (or server) is BUSY. Retrasmit the request later. #SERVER_BUSY -0x06 (see above). #NEGATIVE_ACKNOWLEDGE -0x07 Unsuccessful programming request using function code 13 or 14. #MEMORY_PARITY_ERROR -0x08 SLAVE parity error in MEMORY. #GATEWAY_PROBLEM_PATH -0x0A (-10) Gateway path(s) not available. #GATEWAY_PROBLEM_TARGET -0x0B (-11) The target device failed to repond (generated by master, not slave). #/* Program or connection */ #COMM_TIME_OUT -0x0C (-12) #PORT_SOCKET_FAILURE -0x0D (-13) #SELECT_FAILURE -0x0E (-14) #TOO_MANY_DATAS -0x0F (-15) #INVALID_CRC -0x10 (-16) #INVALID_EXCEPTION_CODE -0x11 (-17) [TRANSACTION_01] MB_TX_CODE=fnct_02_read_discrete_inputs FIRST_ELEMENT=1280 NELEMENTS=8 HAL_TX_NAME=readStatus MAX_UPDATE_RATE=0.0 [TRANSACTION_02] MB_TX_CODE=fnct_15_write_multiple_coils FIRST_ELEMENT=150 NELEMENTS=10 HAL_TX_NAME=remoteIOout MAX_UPDATE_RATE=0.0 [TRANSACTION_03] LINK_TYPE=serial SERIAL_PORT=/dev/ttyS0 SERIAL_BAUD=115200 SERIAL_BITS=8 SERIAL_PARITY=none SERIAL_STOP=2 SERIAL_DELAY_MS=50 MB_SLAVE_ID=1 MB_TX_CODE=fnct_03_read_holding_registers FIRST_ELEMENT=1 NELEMENTS=2 HAL_TX_NAME=XDrive01 MAX_UPDATE_RATE=0.0 DEBUG=1 [TRANSACTION_04] MB_TX_CODE=fnct_04_read_input_registers FIRST_ELEMENT=12 NELEMENTS=3 HAL_TX_NAME=XDrive02 MAX_UPDATE_RATE=10.0 DEBUG=1 [TRANSACTION_05] MB_TX_CODE=fnct_06_write_single_register FIRST_ELEMENT=20 NELEMENTS=1 HAL_TX_NAME=XDrive03 MAX_UPDATE_RATE=0.0 DEBUG=1 [TRANSACTION_06] MB_TX_CODE=fnct_16_write_multiple_registers FIRST_ELEMENT=55 NELEMENTS=8 HAL_TX_NAME=XDrive04 MAX_UPDATE_RATE=10.0 DEBUG=1
5. Pins
5.1. fnct_02_read_discrete_inputs
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mb2hal.m.n bit out
5.2. fnct_03_read_holding_registers
-
mb2hal.m.n.float float out
-
mb2hal.m.n.int s32 out
5.3. fnct_04_read_input_registers
-
mb2hal.m.n.float float out
-
mb2hal.m.n.int s32 out
5.4. fnct_06_write_single_register
-
mb2hal.m.n float in
NELEMENTS
needs to be 1 or PIN_NAMES
must contain just one name.
5.5. fnct_15_write_multiple_coils
-
mb2hal.m.n bit in
5.6. fnct_16_write_multiple_registers
-
mb2hal.m.n float in
m = HAL_TX_NAME
or transaction number if not set, n = element number (NELEMENTS
) or name from PIN_NAMES
Example:
-
mb2hal.00.01.<type>
(transaction=00, second register=01 (00 is the first one)) -
mb2hal.TxName.01.<type>
(HAL_TX_NAME=TxName, second register=01 (00 is the first one))