Page C-6
LiQuilaz II E and S Operations Manual
Appendix C Modbus TCP Protocol
Data Section
The
Data
section contains:
• Calibration Date
• Serial Number
• Device Status
• Device State
• Number of data samples in queue
• Sample Data information
The
Data
section starts with what would have normally been considered configuration
information - calibration date and serial number. This was added to allow for a single
contiguous read when this particular information was desired along with the regular
sample data. If not desired, then start reading at register 30212.
30201:
Calibration Date (Month)
A value between 1 and 12.
30202:
Calibration Date (Day)
A value between 1 and 31.
30203:
Calibration Date (Year)
A value representing the year (e.g., 2017)
30204 - 30211:
Serial Number
Serial number entered using ASCII bytes and positioned as
shown in the map.
30212 - 30213:
Device Status
Dual-register representation of device status. Integer bit mask
matching the current coil selections for convenience. The host
can use this to check for data availability, data format, etc
while reading the data. A separate coil read would not be
required. Values are defined in
30214:
Device State
Least Significant byte (LSB) is State. Most Significant Byte
(MSB) is sub-state. Values are defined in
.
30215:
Number of Data Samples in
the Queue
A value of zero is identical to no data available (coil 00/02 read
as zero).
The queue size setting will determine if the data register
section shows real-time data or stored data. If the queue size
setting has been set to one, the sample data will always
represent the last real-time data packet and the queue value
will be set to one if there is a data packet available. If the queue
size setting is set greater than one, the sample data will
represent the last data queued and the queue value will be set
to one if there is any queued data available.
The two types of data presentation are supported by the same
Modbus register map and are delineated by how the host
system processes the register/coil fields and the instrument
queue setting. The data register section can be forced to show
real-time data by setting the queue size to one or to show
queued data by setting the queue size greater than one.
Queued data is always presented oldest first. The queue size
command is “set queue #” where # is between 1 and 1440.
