Protocols for position value output
Leuze electronic
BPS 8
107
TNT
35/7-2
4
V
9.4.4
Binary protocol 4 request sequences
Cyclical request of position data
The simplest request sequence is the cyclical request with the function identifier
90
d
(5A
h
)
Request position data
. An answer is sent within 4 ms.
With positioning mode enabled, the response contains the defined status information and
the position data. If no valid position data can be determined, the status bit
OUT
is set to 1.
If positioning mode is deactivated, the BUSY response is sent; i.e. the bits
DIA0
to
DIA3
and
the bit
OUT
are set to 1 in the status byte of the response telegram. 0 is sent as a position
value.
Requesting a one-time transmission of position data
In order to obtain as short a response time as possible, the following sequence must be
performed with positioning mode deactivated:
• Request telegram is sent with the function identifier
92
d
(5C
h
) Activate positioning
mode
.
• The BPS activates positioning mode and sends the defined BUSY response within
4 ms.
• After
≥
35ms, a request telegram is sent with the function identifier
91
d
(5B
h
)
Request one-time transmission of position data
.
• Position data are present in the BPS, and the response telegram is sent within 4 ms.
Positioning mode is automatically deactivated.
This sequence is especially suited to position data determination over long distances; i.e.
where position data are required at greater time intervals (100 ... 1,000 ms) and with
reduced precision.
Advantages
:
• Due to the combination of the requests
Activate positioning mode
and
Request
one-time transmission of position data
, a response is sent within 4 ms. With
request cycle times of
≥
35ms, an alternating request from
Activate positioning
mode
and
Request one-time transmission of position data
can be implemented.
• The BPS does not work permanently in positioning mode for requests with the func-
tion identifier
Request one-time transmission of position data
.
Disadvantages
:
• The polling sequence must be actively controlled in the control.