Communication with ID 200/C-PDP 39/84
3 842 540 399/2016-11, MIT: ID 200,
Bosch Rexroth AG
With status FFh (command detected), the second byte of the reply also corresponds
to the second byte of the command call. In the actual reply (status not FFh), the
second byte contains the parameters for the reply, i.e. the number of words of the
reply and the channel the reply comes from. This means that, after a read command, a
reply with status 00 in the reply parameter “Number of words” contains the number of
words of the reply telegram (this is therefore the same as the command call).
With a reply to a write command, the number of words is 0000b, as the reply
contains no (user) data, but just the status. In this case, the second byte of the reply
is not the same as the second byte of the command call. With fixed code commands,
the number of words in the reply is always 0000b. With commands to all connected
antennas (RFIDChannel = 111b), three replies are received: The first reply (status =
FFh) is followed by two replies with the status of the individual channels. Here, the
parameter “RFIDChannel” in the reply telegram contains the number of the relevant
channel (001,010).
If new reply data is available, the previous data is overwritten. The parameterizable
Data Hold Time can be used to define the minimum length of time for which the old
data should be kept before it is overwritten with new data. The basic setting for the
timer value is 0.
New commands may only be sent to the device if the reply for the previous command
has been collected.
“Enhanced” commands are repeated for as long as the commands are in the output
data field. The execution only stops when a new command for the channel on which
the “enhanced” command is executed is written in the output data field.
The reply counter has the value 00h upon switch-on, which is incremented with each
change of the reply data field. This also applies for a change in the status to FFh or
from 00h to 05h (for “enhanced” commands: data carrier leaves the detection area).
In the event of an overflow, the counter jumps from FFh to 01h.
7.3.4
Command types
When using the commands, we differentiate between the two operation modes
“single mode” and “enhanced mode”.
Single mode
The command is carried out once. A reply is given right away.
Enhanced mode
The command remains permanently active until it is cancelled by the user or an error
message. A reply is given right away.
The command remains active after the reply. Data is only transmitted if data carriers
change. Data carriers are not read twice. If a data carrier leaves the read area, the
status ‘5’ is output.
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