Operating Instructions OXY5500 Gas Analyzer
56 Endress+Hauser
6.1.3.2 Int32
All int32 values are 32 bit-wide integer values. The example given in the previous section applies here as well.
6.1.3.3 Character
The definition is as follows:
8 bit ASCII-Code table according to ISO-8859-1 (Latin-1 Western European)
A register always holds exactly 2 characters. Unused bytes are filled with zeros (ASCII: 0x00).
6.1.3.4 Boolean
Boolean registers are 16bit int32 registers with only 0 and 1 as allowed values.
6.1.4 Error response
The error response follows the Modbus definition, but only four exception codes are implemented:
• 1 (Illegal function): An unsupported function code was used.
• 2 (Illegal data address): The requested register is either not available or write-protected.
• 3 (Illegal data value): The value could not be set. The value was out of range. The last correct value will be
restored.
• 6 (Slave device busy): This code appears when there is an “active” USB connection (communication via software
is active).
6.1.5 Different communication channels
The OXY5500 has multiple ways to read and set its settings and measurement values:
• Modbus Communication
o RS-485
o RS-232
• Ethernet
• USB Service Port
• Via keypad and LCD
All options share the same fundamental memory. Changing the settings via one communication channel will alter
the expected result on another channel.
6.1.5.1 Recommendation
One channel should be used to set up the device completely. As the device will save every setting and allows
immediate checking of the results, it is recommended to do this via keypad and LCD and to use the other channels as
simple data-polling options.
If there is a Service Software connected (via USB), the Modbus write command 16 (“Write multiple registers”)
will always return error code 6.
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