Kamstrup MULTICAL 402, Техническое описание, Страница: 82 / 113

MULTICAL® 402
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Kamstrup A/S · Technical Description · 5512-742_M1_GB_01.2016
12 Data Communication
12.1 MULTICAL
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Internal data communication in MULTICAL
402 Data Protocol
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The KMP protocol is used in all Kamstrup consumption meters launched from 2006 onwards. The protocol is used
for the optical eye and via plug pins for the module area. Thus, modules with e.g. M-bus interface use the KMP
protocol internally and the M-bus protocol externally.
402 is based on the Kamstrup Meter Protocol (KMP) which provides a
quick and flexible reading structure and also fulfils future requirements to data reliability.
The KMP protocol has been designed to handle point to point communication in a master/slave system (e.g. a
bus system) and is used for data reading of Kamstrup energy meters.
Software and parameter protection
The meter’s software has been implemented in a Flash and cannot be changed, neither deliberately nor by
mistake. The legal parameters cannot be changed via data communication without breaking the legal seal and
short circuiting the ”total programming lock”.
Software conformity
Software check sum, based on CRC16, is available via data communication and in the display.
Integrity and authenticity of data
All data parameters include type, measuring unit, scaling factor and CRC16 check sum.
Every produced meter includes a unique identification number.
Two different formats are used in the communication between master and slave. Either a data frame format or an
application acknowledgement format.
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A request from master to slave is always sent in a data frame
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The response from the slave can either be sent in a data frame or as an application acknowledgement
The data frame is based on the OSI model using the physical layer, the data link layer and the application layer.
Number of bytes in
each field 1 1 1 0-? 2 1
Field designation
Start byte Destination
address
CID Data CRC Stop byte
OSI – layer Application layer
Data link layer
Physical layer
The protocol is based on half duplex serial synchroneous communication with setup: 8 data bits, no parity and 2
stop bits. The data bit rate is 1200 or 2400 baud. CRC16 is used in both request and response.
Data is transferred byte for byte in a binary data format, where the 8 data bits represent one byte of data.
Byte Stuffing is used for extending the value range.