Modbus is a protocol originally developed by Modicon for communicating with industrial PLCs (Program Logic Control). A Circon 400-series controller can communicate using the Modbus protocol using its built-in RS-485 port (supported on both the UHC-400 and SCC-410).
Modbus programming blocks allow a 400-series controller to communicate with Modbus slave devices using the Modbus RTU protocol. In doing so, the 400-series controller acts as a master device.
Modbus blocks can only be dropped on a “Modbus Device page”.
►To add a Modbus Device page:
▪Click File > New > Modbus Device Page.
A Modbus device page has the following properties:
Properties |
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Slots |
Description |
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SlaveAddr |
The address of the Modbus slave device. |
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Float32Format |
Specifies the byte order for 32‑bit floating point registers for use on a device that supports 32‑bit numbers. |
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SignedInt32Format |
Specifies the byte order for 32‑bit integer registers for use on a device that supports 32‑bit numbers. |
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Communication properties can be specified to control communications with the slave device using the following steps:
1.Click View > Modbus Service Configuration. This displays the Modbus Service Configuration dialog:
