SHM Modbus - Getting Started

SHM Modbus > Getting Started

“This getting started section demonstrates setting up a Shared Memory Modbus client and simulating register data.”

1. Start Modbus client

modbus-tcp-client-shm --semaphore modbus -p 5020

This command starts a shared memory Modbus TCP client listening on port 5020. It creates the shared memories modbus_DO, modbus_DI, modbus_AO and modbus_AI, and creates the semaphore modbus to protect the shared memory from simultaneous access.

For more details about using the Modbus clients see modbus-tcp-client-shm and modbus-rtu-client-shm.

2. Interact with the shared memory

SHM Modbus provides tools to inspect and manipulate the Modbus client data.

Write data

• write-shm: write any data to a shared memory. (available via the GUI)
• shared-mem-random: write random data to a shared memory (available via the GUI)
• stdin-to-modbus-shm: write values (with specified data type) to registers.
• shm-modbus-signal-gen: signal generator that generates input for stdin-to-modbus-shm

Inspect data

• dump-shm: outputs shared memory data to stdout. Can be used in combination with the hexdump command to create a hexdump of a shared memory. (The hexdump functionality is available via the GUI.)
• shm-format: reads data with a specified data type from shared memory.