HyQuest Solutions iRIS 350FX, Руководство пользователя

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iRIS 350FX Reference Manual V1.50
77 HyQuest Solutions (NZ) Ltd - PO Box 9466, Hamilton, New Zealand Tel: +64 7 857-0810 Email: support@hyquestsolutions.co.nz
11 Using Modbus Slave Mode
The Modbus protocol slave mode support is a feature supported by the standard iRIS 350FX program variants.
Custom variants do not have support for this feature as the RS232 port is often used by these in a different
way.
When enabled, the iRIS functions as a simple Modbus slave (server). Third party equipment is the master and
can write values to or read values from a set of predefined “holding registers”. In the case of the written
holding registers, the iRIS 350FX can be configured to access these values as sources for one or more sensor
channels.
In order to enable the Modbus operation on the shared RS232 port, the user must do this with the
keypad/LCD interface when on site. If Modbus mode is configured, a safety timeout switches back to Modbus
after a period of no activity on the port, in the event a user forgets to manually reselect that mode.
The iRIS 350FX operates in Modbus RTU mode (Modbus ASCII mode will be added at a later date). Supported
port speeds are 1200, 2400, 4800, 9600, 19200, 38400 and 115200bps. Parity in RTU mode is settable to
Even, Odd or None. In compliance with the Modbus specification, when parity is set to ‘None’, an extra stop
bit is inserted. In RTU mode, 8 data bits are used and in ASCII mode, 7 data bits are used.
If the RTU is writing values to the iRIS frequently, then the iRIS can log a period average and minimum and
maximum values during the log period as well.
There is also a basic write timeout where the holding registers are set to an invalid value after a
predetermined time of no write commands being received from the Modbus master. This can be disabled by
setting the timeout to zero.
Configuring iRIS 350FX to use Modbus
This section explains how to configure an iRIS 350FX to use Modbus input in iLink 2012.
Connect the logger using iLink 2012 and go to the General settings under the Configuration tab. Expand the
sensors tree. In the screenshot on the next page, sensor 12 (Modbus) is selected and the ‘Modbus 2 Byte
Short’ has been chosen from the source dropdown list. So it will use the values that are written to holding
register 40112 for logging (2 Byte Shorts are written in registers 40101-40120 and 4 Byte Floats are written
in registers 40201-40240).