Pressure Systems 9046 - Manual (Page 55)

Pressure Systems, Inc. Model 9046 User’s Manual
Page 49 www.PressureSystems.com
5.7.2 Command ’c’- Sub-command Index 01: Start Stream(s)
This sub-command is used to start the delivery of any previously configured host stream in a
module. If the stream started is "unbounded", then it will be necessary to use the Stop Stream
sub-command to stop it. Otherwise, a bounded stream will end automatically if a finite number
of scans has been specified for it. This sub-command may also be used to resume a previously
stopped host stream that has not transmitted all requested data scans. The sub-command’s
format is:
Command "c 01 st"
’c’ is the operation code
’01’ is the sub-command index (’ii’) for Start
Stream(s)
’st’ is the stream id digit (1, 2, or 3, or 0=all streams)
NOTE: all parameters are separated by a space
character.
Response "A" or "Nxx" ’A’ for acknowledge; ’N’ for negative
acknowledge, error code xx.
Autonomo
us Packet "tssss[pp] [dddd] .. [dddd]"
’t’ is a 1-byte binary (8-bit) value identifying the
stream number (1-3).
’ssss’ is a 4-byte binary integer (32-bit, big-endian)
scan sequence. number. Optional binary status may
follow the sequence number. (See "05" sub-
command.)
’pp’ is an optional 2-byte binary (16-bit, big-endian)
UTR Thermal Alarm Bit Map (one bit per channel 16-
1, left-to-right, 1=in alarm, 0=not in alarm)
’ dddd’ are the acquired datum values for each
selected channel of each selected group, in the
selected format. Each formatted datum is a 9, 13, or
17 byte ASCII string with one or more leading space
characters (except the binary formats (f=7 or 8) which
are contiguous 4-byte IEEE floats in big- or little-
endian, respectively)
Description : This sub-command starts a particular specified host stream (st=1-3), or starts all
configured host streams with a single command (st=0). Each autonomous host stream scan
begins with a 5-byte fixed-format (binary) data header (tssss). The first byte (t) identifies the
host stream, while a 32-bit unsigned binary (big-endian) sequence number (ssss) completes the
header. This sequence number will start at one (1) for the first scan returned by a stream and
increment for each other returned scan of that stream. In the case of an unbounded data
stream, the sequence number may overflow the maximum permissible 32-bit integer value. If
this occurs, the sequence number value will wrap around to zero (0) following the largest 32-bit
(unsigned) value (4294967295) and then continue to increment by one for each returned scan.
The sequence number field is intended to provide a mechanism for host software to ensure that
host data stream scans are processed or stored in the order in which they were obtained by the