Heinzmann Triton OMD, Manual

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7 General communication functions overview
22 Triton OMD CAN protocol / Rev.-No. 03
7.4.1 Configuration parameter set
For sensor to be configured with valid OMD parameter set, master sends corresponding pa-
rameter values within special configuration telegram kSensorConfigDataTel1 to the sensor
device.
OMD Parameter Set is specified in the table below.
No. Indicated value External value range Unit Internal value range
117 OMConcAlaramLevel 0.00 – 20.00 mg/l 0 - 65535
118 OMConcPrealaramLevel 0.00 – 20.00 mg/l 0 - 65535
119 TempAlarmLevel -128.0 – 128.0 °C 0 - 65535
120 TempPrealarmLevel -128.0 – 128.0 °C 0 - 65535
Tab. 7.1 OMD parameter set
7.4.2 CRC check sum calculation
Both OMD devices, evaluator and sensor, use the same MCU type with embedded cyclic re-
dundancy check (CRC) module. The modules are configured for Standard CCITT CRC16
Check Sum with following specification:
• Width = 16 bits;
• Polynomial = 0x1021;
• Initial value (Seed) = 0xFFFF;
• Input data is 8bits at a time, providing all bytes continuously;
• Input data is not transposed;
• Output CRC is not transposed;
• No XOR is performed on the output CRC.
Values 0x0000 and 0xFFFF are not allowed as a final CRC value, calculated through desired
data set. In such cases 0x0001 is returned instead.