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Minor updates and fixes.
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@interkosmos
interkosmos committed Jul 8, 2024
1 parent 3962685 commit 012d53f
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Showing 2 changed files with 106 additions and 46 deletions.
148 changes: 104 additions & 44 deletions src/dm_modbus.f90
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Original file line number Diff line number Diff line change
Expand Up @@ -3,11 +3,8 @@
module dm_modbus
!! Abstraction layer over _libmodbus_, for Modbus RTU/TCP communication.
!!
!! You may want to use functions available in module _dm_util_ to convert
!! unsigned and signed integers:
!!
!! * `dm_uint16_to_int32()`
!! * `dm_int32_to_uint16()`
!! You may want to use function `dm_to_signed()` available in module
!! `dm_compat` to convert unsigned to signed integers.
!!
!! Use Modbus function code `0x03` to read holding registers from a Modbus
!! RTU connection:
Expand All @@ -20,23 +17,23 @@ module dm_modbus
!! ! Create Modbus RTU context and connect to device 10.
!! rc = dm_modbus_create(modbus = modbus, &
!! path = '/dev/ttyUSB0', &
!! baud_rate = TTY_B115200, &
!! baud_rate = TTY_B19200, &
!! byte_size = TTY_BYTE_SIZE8, &
!! parity = TTY_PARITY_NONE, &
!! stop_bits = TTY_STOP_BITS2)
!! parity = TTY_PARITY_EVEN, &
!! stop_bits = TTY_STOP_BITS1)
!! rc = dm_modbus_connect(modbus)
!! rc = dm_modbus_set_slave(modbus, slave=10)
!!
!! ! Read and output two registers.
!! rc = dm_modbus_read_registers(modbus, address=0, registers=regs)
!! rc = dm_modbus_read_registers(modbus, address=50, registers=regs)
!!
!! do i = 1, size(registers)
!! s = dm_uint16_to_int32(regs(i))
!! s = dm_to_signed(regs(i))
!! print '("regs(", i0, ") = ", i0, " (0x", z0, ")")', i, s, s
!! end do
!!
!! ! Print the two registers as float.
!! print '(f12.8)', dm_modbus_get_float(regs)
!! ! Print the two registers as real in ABCD byte order.
!! print '(f12.8)', dm_modbus_get_real_abcd(regs)
!!
!! ! Disconnect and clean-up.
!! call dm_modbus_close(modbus)
Expand All @@ -53,6 +50,7 @@ module dm_modbus
use :: modbus
use :: modbus_rtu
use :: modbus_tcp
use :: dm_compat
use :: dm_error
use :: dm_kind
implicit none (type, external)
Expand All @@ -63,14 +61,22 @@ module dm_modbus
integer, parameter, public :: MODBUS_MODE_RTU = 1 !! Modbus RTU (Remote Terminal Unit).
integer, parameter, public :: MODBUS_MODE_TCP = 2 !! Modbus TCP (Transmission Control Protocol).

integer, parameter :: FALSE = 1
integer, parameter :: TRUE = 1
! Byte orders of 32-bit real values.
integer, parameter, public :: MODBUS_REAL_ABCD = 0 !! ABCD byte order.
integer, parameter, public :: MODBUS_REAL_BADC = 1 !! BADC byte order.
integer, parameter, public :: MODBUS_REAL_CDAB = 2 !! CDBA byte order.
integer, parameter, public :: MODBUS_REAL_DCBA = 3 !! DCBA byte order.

interface dm_modbus_create
!! Generic function to create Modbus RTU or TCP context.
module procedure :: dm_modbus_create_rtu
module procedure :: dm_modbus_create_tcp
end interface
character, parameter :: PARITY_NONE = 'N'
character, parameter :: PARITY_EVEN = 'E'
character, parameter :: PARITY_ODD = 'O'

! From module `modbus_rtu`.
public :: MODBUS_RTU_RS232
public :: MODBUS_RTU_RS485
public :: MODBUS_RTU_RTS_NONE
public :: MODBUS_RTU_RTS_UP
public :: MODBUS_RTU_RTS_DOWN

type, public :: modbus_type
!! Opaque Modbus RTU/TCP context type.
Expand All @@ -79,18 +85,22 @@ module dm_modbus
type(c_ptr) :: ctx = c_null_ptr !! C-pointer to Modbus context.
end type modbus_type

public :: MODBUS_RTU_RS232
public :: MODBUS_RTU_RS485
public :: MODBUS_RTU_RTS_NONE
public :: MODBUS_RTU_RTS_UP
public :: MODBUS_RTU_RTS_DOWN
interface dm_modbus_create
!! Generic function to create Modbus RTU or TCP context.
module procedure :: dm_modbus_create_rtu
module procedure :: dm_modbus_create_tcp
end interface

public :: dm_modbus_close
public :: dm_modbus_connect
public :: dm_modbus_destroy
public :: dm_modbus_error_message
public :: dm_modbus_flush
public :: dm_modbus_get_float
public :: dm_modbus_get_real
public :: dm_modbus_get_real_abcd
public :: dm_modbus_get_real_badc
public :: dm_modbus_get_real_cdab
public :: dm_modbus_get_real_dcba
public :: dm_modbus_get_serial_mode
public :: dm_modbus_get_slave
public :: dm_modbus_mode
Expand Down Expand Up @@ -134,7 +144,7 @@ integer function dm_modbus_create_rtu(modbus, path, baud_rate, byte_size, parity

type(modbus_type), intent(out) :: modbus !! Modbus type.
character(len=*), intent(in) :: path !! Device path.
integer, intent(in) :: baud_rate !! Baud rate enumerator (`TTY_B_*`).
integer, intent(in) :: baud_rate !! Baud rate enumerator (`TTY_B*`).
integer, intent(in) :: byte_size !! Byte size enumerator (`TTY_BYTE_SIZE*`).
integer, intent(in) :: parity !! Parity enumerator (`TTY_PARITY_*`).
integer, intent(in) :: stop_bits !! Stop bits enumerator (`TTY_STOP_BITS*`).
Expand All @@ -148,7 +158,7 @@ integer function dm_modbus_create_rtu(modbus, path, baud_rate, byte_size, parity
if (.not. dm_tty_valid_parity(parity)) return
if (.not. dm_tty_valid_stop_bits(stop_bits)) return

! Byte size (start bits).
! Byte size: 5, 6, 7, 8 (start bits).
select case (byte_size)
case (TTY_BYTE_SIZE5)
byte_size_ = 5
Expand All @@ -160,24 +170,24 @@ integer function dm_modbus_create_rtu(modbus, path, baud_rate, byte_size, parity
byte_size_ = 8
end select

! Stop bits.
! Parity: none, odd, even.
select case (parity)
case (TTY_PARITY_NONE)
parity_ = PARITY_NONE
case (TTY_PARITY_ODD)
parity_ = PARITY_ODD
case (TTY_PARITY_EVEN)
parity_ = PARITY_EVEN
end select

! Stop bits: 1, 2.
select case (stop_bits)
case (TTY_STOP_BITS1)
stop_bits_ = 1
case (TTY_STOP_BITS2)
stop_bits_ = 2
end select

! Parity.
select case (parity)
case (TTY_PARITY_NONE)
parity_ = 'N'
case (TTY_PARITY_EVEN)
parity_ = 'E'
case (TTY_PARITY_ODD)
parity_ = 'O'
end select

rc = E_MODBUS
modbus%mode = MODBUS_MODE_RTU
modbus%ctx = modbus_new_rtu(path, baud_rate, parity_, byte_size_, stop_bits_)
Expand Down Expand Up @@ -237,12 +247,63 @@ integer function dm_modbus_flush(modbus) result(rc)
rc = E_NONE
end function dm_modbus_flush

real function dm_modbus_get_float(registers) result(value)
integer function dm_modbus_get_real(registers, byte_order, value) result(rc)
!! Returns real value from two registers of given byte order in argument
!! `value`. The argument byte order must be one of the following:
!!
!! * `MODBUS_REAL_ABCD`
!! * `MODBUS_REAL_BADC`
!! * `MODBUS_REAL_CDAB`
!! * `MODBUS_REAL_DCBA`
!!
!! The function returns `E_INVALID` on any other value.
integer(kind=u2), intent(inout) :: registers(2) !! Registers to convert.
integer, intent(in) :: byte_order !! Byte order.
real, intent(out) :: value !! Returned real value.

rc = E_NONE

select case (byte_order)
case (MODBUS_REAL_ABCD)
value = modbus_get_float_abcd(registers)
case (MODBUS_REAL_BADC)
value = modbus_get_float_badc(registers)
case (MODBUS_REAL_CDAB)
value = modbus_get_float_cdab(registers)
case (MODBUS_REAL_DCBA)
value = modbus_get_float_dcba(registers)
case default
rc = E_INVALID
end select
end function dm_modbus_get_real

real function dm_modbus_get_real_abcd(registers) result(value)
!! Returns real value from two registers in ABCD byte order.
integer(kind=u2), intent(inout) :: registers(2) !! Registers to convert.

value = modbus_get_float_abcd(registers)
end function dm_modbus_get_real_abcd

real function dm_modbus_get_real_badc(registers) result(value)
!! Returns real value from two registers in BADC byte order.
integer(kind=u2), intent(inout) :: registers(2) !! Registers to convert.

value = modbus_get_float_badc(registers)
end function dm_modbus_get_real_badc

real function dm_modbus_get_real_cdab(registers) result(value)
!! Returns real value from two registers in CDAB byte order.
integer(kind=u2), intent(inout) :: registers(2) !! Registers to convert.

value = modbus_get_float_cdab(registers)
end function dm_modbus_get_real_cdab

real function dm_modbus_get_real_dcba(registers) result(value)
!! Returns real value from two registers in DCBA byte order.
integer(kind=u2), intent(inout) :: registers(2) !! Registers to convert.

value = modbus_get_float_dcba(registers)
end function dm_modbus_get_float
end function dm_modbus_get_real_dcba

integer function dm_modbus_get_serial_mode(modbus, mode) result(rc)
!! Gets the current Modbus RTU serial mode (RS-232 or RS-485).
Expand Down Expand Up @@ -341,13 +402,12 @@ integer function dm_modbus_set_debug(modbus, debug) result(rc)
type(modbus_type), intent(inout) :: modbus !! Modbus type.
logical, intent(in) :: debug !! Enable debug mode.

integer :: d
integer :: debug_

d = FALSE
if (debug) d = TRUE
debug_ = dm_f_c_logical(debug)

rc = E_MODBUS
if (modbus_set_debug(modbus%ctx, d) == -1) return
if (modbus_set_debug(modbus%ctx, debug_) == -1) return

rc = E_NONE
end function dm_modbus_set_debug
Expand Down
4 changes: 2 additions & 2 deletions test/dmtestmodbus.f90
View file
Original file line number Diff line number Diff line change
Expand Up @@ -59,8 +59,8 @@ logical function test02() result(stat)
stat = TEST_FAILED
regs = 0_u2

print *, 'Converting registers to float ...'
r = dm_modbus_get_float(regs)
print *, 'Converting registers to real ...'
r = dm_modbus_get_real_abcd(regs)
print '(" Value: ", f5.3)', r
if (.not. dm_equals(r, 0.0)) return

Expand Down

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