Pulsar blackbox 134, Instruction Manual

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Latency
The time taken for the level
blackbox
134 to process a message and start the
transmission of a reply is called the latency. This does not include the time
taken to transmit the request or reply.
The parameter functions read 1 word (function code 03), write 1 word
(function code 06) and Loopback (function code 08) are processed within
the latency of between 20 and 100 ms.
For parameter functions, read N bits (function 01), read N words (function
03 or function 04) and write N words (function 16) the latency is
indeterminate. The latency will depend on the instrument activity and the
number of parameters being transferred and will take from 100 to 500 ms
approximately.
It is possible to artificially increase the latency by setting the Comms Delay
parameter in the Set Up configuration list. This is sometimes required to
allow a guaranteed gap between requests and responses needed by some
RS485 adapters to switch from transmit to receive states.
Message Transmission Time
The time required to transmit a message will depend on the length of the
message and the baud rate.
To find the number of bytes, refer to the relevant function code. The three
extra bytes are for the end of transmission characters
The number of bits per character will be ten, or eleven if a parity bit is used.
(For Modbus RTU: 1 start bit, 8 data bit, an optional parity bit and 1 stop
bit)
For example, reading a single word with the function code 03 at 19200 baud
no parity bit)
The wait period for this transmission will exceed 22.5 ms (6 + 6.5 + 10.0)
For a broadcast command (device address 0) the master would not expect a
reply. In this case the wait period will exceed 16 ms (6 + 10.0)
BaudRate
racter BitsPerCha tes NumberOfBy
onTime Transmissi
* ) 5 . 3 * (

ms on transmissi 6
19200
10 * ) 5 . 3 * 8 (
 
ms response 5 . 6
19200
10 * ) 5 . 3 * 9 (
 