Page B-10
LiQuilaz II E and S Operations Manual
Appendix B RS-485 Communication Protocol
Fast Protocol
The Fast communication protocol allows the Data Display System to acquire the most
recent data for the sample in progress. This mode operates concurrently with, and
independently of, the Slow protocol mode. To initiate a Fast poll, the Data Display
System need only transmit the address of the desired device. The address of a device
that supports the Fast communication mode is the same as the address of the Slow
mode, except that the most significant bit of the address will be set. For example: if the
device’s network address is 1, the address for the Fast mode is 129).
The following information is transmitted back to the Data Display System per each
poll:
1) ADDRESS
A one-byte device address.
2) SAMPLE_INTERVAL
A 4-byte unsigned number that is the time elapsed since the start of the
sample. (56th of a second)
3) LASER/FLOW STATUS
bit n.1
=
Laser Status 1 = Laser Good
Laser Status 0 = Laser Bad
bit n.2
=
Not Used
bit n.3
=
Flow Rate 1 = Flow Rate Good
Flow Rate 0 = Flow Rate Bad
bit n.4
=
Not Used
bit n.5
=
Not Used
bit n.6
=
Not Used
bit n.7
=
Not Used
bit n.8
=
Not Used
NOTE:
The bit n.3 is only valid in the time-based mode.
The bit n.3 is the sample signal line for the sample-based
mode.
4) SAMPLE_STATUS
Time-base mode only:
A 1-byte number. The most significant bit represents the sampling
status. The low 7 bits represents the Queue Count. The Queue Count in
the Slow and Fast protocols are identical.
Sampler base mode:
Status=1
Sampling
Status=0
Not Sampling
5) DC_LIGHT
A 2-byte unsigned numberDC Light that is the DC Light voltage in steps
of 2.44 mv/bit (i.e., 4095 = 10 Volts).
6) NUMBER_CHANNELS
A 1 byte number that is the number of channels currently programmed
into the device.
7) unsigned long CHANNELn
A 4-byte number that is the number of particles found in the nth
channel. CHANNEL 1 has the smallest size threshold. Each channel is an
unsigned long counter. If the device is programmed to have n = 16
channels, a total of 64 bytes can be expected back in this field. See the
examples on pages page
8) CHECK_SUM
A 2-byte value that is the sum of all the bytes in the “unformatted data
packet” with the exception of the STX, ETX, and checksum itself. The
carry bit in the addition is ignored. It is transmitted as Low Byte, High
Byte.
