t
1
= (10 X # of characters) / baud rate
At the start of time interval t
2
, the controller starts the interpretation of the
command and when complete, performs the command function. This time
interval varies from 2 msec to 100 msec. If no response from the controller is
expected, the controller is ready to accept another command at the end of t
2
.A
minimum delay of 100 msec for period t
2
must be observed before sending
another command to the same controller.
If the controller is to reply with data, the time interval t
2
is controlled by the
use of the command terminating character. The standard command line
terminating character is ‘*’. This terminating character results in a response
time window of 100 msec minimum and 200 msec maximum. This allows
sufficient time for the release of the bus by the transmitter. Terminating the
command line with ‘$’ results in a response time window (t
2
)of2msec
minimum and 100 msec maximum. The faster response time of this
terminating character requires that the transmitter release within 2 msec after
the terminating character is received.
At the beginning of time interval t
3
, the controller responds with the first
character of the reply. As with t
1
, the time duration of t
3
is dependent on the
number of characters and baud rate of the channel.
t
3
= (10 X # of characters) / baud rate.
The number of response characters varies depending on the setting of the
full / abbreviated transmissions parameter. At the end of t
3
, the controller is
ready to receive the next command.
The maximum serial throughput of the controller is limited to the sum of:
t
1
,t
2
and t
3
.
Full Field Controller Transmission Byte Format
The first two characters transmitted are the node address, unless the node
address assigned = 0, in which case spaces are substituted. A space follows
the node address field. The next three characters are the register ID. The
numeric data is transmitted next. The numeric field is 5-6 characters long. If
the decimal point is present, the field is 6 characters. Negative values have a
leading minus sign. The data field is right justified with leading spaces.
Engineering Units byte is next. The end of the response string is terminated
with a carriage return <CR> and line feed<LF>. When print block
transmission is finished, an extra <SP><CR><LF> is used to provide
separation between the blocks.
Byte Description
1-2 2 byte Node Address field [00-99]
3 <SP> (Space)
4-6 3 byte Register ID field
7-12 6 byte data field, 4 bytes for number, one byte for sign, one byte
for decimal point
13 1 byte Engineering Units
14 <CR>
15 <LF>
16 <SP>(Space). This character only appears in the last line of a print
block.
17 <CR> This character only appears in the last line of a print block.
18 <LF> This character only appears in the last line of a print block.
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