DEV 1953, Руководство пользователя

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User Manual DEV 1953

Copyright DEV Systemtechnik GmbH 2015-2017 95
5.6 Control via Remote Interface: Sandar Prosan Protocol
5.6.1 Sandar Prosan Protocol Overview
Messages between the device and the host are transferred as records, i.e. data
between unique start and stop characters. Once a complete record is received, the
receiver returns the character
<ACK>
if the record is correctly received and recog-
nized. If the record is incorrectly received, not recognized, or not available, the
receiver returns a
<NAK>
character. If the transmitter receives
<NAK>
(or no answer
e.g. within two seconds), it retransmits the message. The number of retransmis-
sions and delays before a retransmission varies and depends on the current system.
Each record comprises a checksum that is inserted -as two characters in hexa-
decimal notation- between the last data character and the stop character of the
record. The checksum is calculated by the modulo 256 sum of all data characters in
the record.
The record start character
<STX>
, the record stop character
<ETX>
, the acknowledge
character
<ACK>
, and the not-acknowledge character
<NAK>
cannot be transmitted as
data characters.
Note:

The Sandar Prosan protocol is available only if "Prosan" is selected within the
CPH setup of the Web Interface; please refer to chapter 5.5.7.2.3. The protocol
is exclusively available via the serial interface; the settings of the serial inter-
face have to be configured accordingly (chapter 4.4.1.2).

If "Echo in Local Mode" is disabled (factory default), the device responds in
Local Mode with an
<ACK>
character to the commands
Q
,
XR
,
AM
,
AMA
,
S
, or
SA
,
only. If enabled, the responses are equivalent to the responses in
Remote Mode.
"Echo in Local Mode" can be disabled or enabled within the CPH setup of the
Web Interface or via the device specific
PME
y
commands (chapter 5.6.3.7).

The device specific
PM
xy
commands (chapters 5.6.3.6…5.6.3.9) are not part of
the protocol standard and can be executed in Remote Mode or in Auto Mode.

For testing purposes, the Sandar Prosan tool WinProTest v1.01 by Telecast
Norge AS may be used to issue Sandar Prosan commands.
5.6.2 Sandar Prosan Protocol Communication Structure
The basic command structure is:
Command:
<STX><command><checksum><ETX>
Notation:
<STX>
= record start character (=
0x02
)
<ETX>
= record stop character (=
0x03
)
<ACK>
= acknowledge (complete record received) character (=
0x06
)
<NAK>
= not-acknowledge (incorrect record received) character (=
0x15
)
Note:

(Initially) always a
<ACK>
or
<NAK>
character is returned as a response to a
command.

The switching command (
M
, chapter 5.6.3.5) can be executed in Remote Mode
only.