Wingpath to cease trading on 25 October 2025
From 25 October 2025 we will no longer be selling licences for our software products (ModSnmp, ModMultiSim, Modsak, ModSlaveSim, ModMaster and ModTest).
The website will remain operational until at least 2027 for reference purposes, and for the registration and transfer of product licences.
Modsak Manual v3.16 - 4. File Registers
File registers are used to store the values read and written by the Read File Record (function code 20) and Write File Record (function code 21) commands.
In slave mode, you must define some file registers if you want Modsak to send valid responses to Read File Record and Write File Record commands.
In master mode, you can send Read File Record and Write File Record commands using the Define Command page, without needing to define any file registers. Alternatively, you can define some file registers, as described in the following sections, and use the File Register Table buttons to request file register reads and writes.
Note that file registers are referred to by several different names in the Modbus specifications. They are variously called "file records", "registers" and "references" in the current Modbus specification, and they are called "General References" or "Extended Memory file (6x) references" in the original Modbus specification and the Modbus/TCP specification (with the corresponding commands being called "Read General Reference" and "Write General Reference").