![FMC Technologies Smith Meter microFlow.net Liquid Manual Download Page 27](http://html.mh-extra.com/html/fmc-technologies/smith-meter-microflow-net-liquid/smith-meter-microflow-net-liquid_manual_2312633027.webp)
Issue/Rev. 0.1 (9/13) ║ MNFL003 • Page 27
microFlow.net Liquid Modbus Communications Manual
Appendix
4.52 Address
The address is the first field in the frame and consists of one byte (eight bits) of informa-
tion. The address is the unique identification of the microFlow.net Liquid (slave) that is to
receive the message that is sent via the supervisory system (master). Each microFlow.
net Liquid address must be unique so that only the addressed slave will respond to a
query. The address is also part of the response message sent back to the master from
the microFlow.net Liquid when data is requested. By returning the address as part of the
response, the master can tell which of the microFlow.net Liquids the data is coming from.
4.6
Query Responses
The first two fields of the response to the read only message are identical to the com-
mand. The microFlow.net Liquid returns the address and the function code that was
transmitted to the unit. The next field is the byte count.
4.61
Byte Count
The byte count is sent to the master (supervisory system) indicating how much data is
being sent from the microFlow.net Liquid. In the example shown, the command requested
data from these registers and each register contains two bytes of data.
4.62
Data Register
Each of the data registers of unsigned characters contains two bytes of data. The
response message returns the data with the most significant byte of data first and the
least significant byte second. Data can be requested and returned from a number of
registers with a single interrogation message. The limit on the amount of data returned
from the microFlow.net Liquid to the master is 256 bytes. The data lengths for the data
types currently used by the microFlow.net Liquid are as follows:
Data Length
Type
Binary
Double
8 bytes
Integer
2 bytes
Long Integer
4 bytes
Text String
variable length
Character
2 bytes (high order byte set to zero)
CRC-16
2 bytes
Float
4 bytes
Unsigned Integer
2 bytes
Unsigned Long
4 bytes
Unsigned Character
2 bytes (high order byte set to zero)
The error checking sequence is the same as described in the paragraph under Read
Only Message.