ICC ETH-1000, Инструкция по эксплуатации

Страница: 255 / 281

254
ICC
successfully receiving the unit’s response. The reason for this is because
the gateway will then experience an error when attempting to respond via the
now-closed socket, which will immediately trigger the timeout action. Always
be sure to manage socket life cycles “gracefully”, and do not abandon
outstanding requests.
•
If a socket timeout occurs (regardless of whether it was due to a
communication lapse or abnormal socket error), the driver will trigger a
timeout event as described in section 8.3.
•
32-bit register accesses are supported in a variety of options and formats.
11.12.1.2.2 Holding & Input Register Mappings
The Modbus/TCP server driver provides read/write support for holding registers
(4X references) and read-only support for input registers (3X references). Both
holding registers and input registers access the same data. For example, reading
Holding Register 4 returns the same data as reading Input Register 4. By default,
registers are mapped into the database using the following scheme:
Register 1 is mapped to address 0,
Register 2 is mapped to address 2,
Register 3 is mapped to address 4,
:
Arithmetically, the register-to-address relationship can be described via Equation
7:
) ( 1 register 2 address
− × =
Equation 7
Additionally, a register remap object can be created to map a register to a
different address in the database, or to map a register that is outside of the
default mapping into the database. Refer to section 8.7.12.3 for more information
on configuring register remap objects.
For clarity, let’s use Equation 7 in a calculation example with a remap object.
Let’s assume we have defined a register remap object to remap register 25 to
database address 62. This means that instead of register 25 mapping to address
48 (as it would with the default mapping), it will now map to address 62. Now say
we wish to read registers 24 and 25. We already know that register 25 maps to
database address 62, so we must use Equation 7 to calculate what address
register 24 is mapped to. Using the equation, we can determine that register 24 is
mapped to database address 46. So reading registers 24 and 25 will return data
from addresses 46 and 62 in the database, respectively.
11.12.1.2.3 Coil & Discrete Input Mappings
The Modbus/TCP server driver provides read/write support for coils (0X
references) and read-only support for discrete inputs (1X references). These will
collectively be referred to from here on out as simply “discretes”. Accessing