Printed in the Federal Republic of Germany
TR-Electronic GmbH 2018, All Rights Reserved
06/21/2018
TR - ELA - BA - DGB - 0028 - 00
Page 63 of 84
4.4 Switching on the supply voltage
After the connection and all hardware settings have been carried out, the supply
voltage can be switched on.
The measuring system is initialized first of all and is then in
NMT_CS_NOT_ACTIVE
state. In this state the measuring system is passive (listen only), observes the network
traffic, does not send any frames and is waiting for MN commands. The measuring
system can be gradually transferred to
NMT_CS_OPERATIONAL
state according to the
NMT CN State Machine
via the MN:
NMT_CS_PRE_OPERATIONAL_1
With a
SoA
or a
SoC
frame the measuring system is switched into
NMT_CS_PRE_OPERATIONAL_1
. In this state the measuring system sends a frame
only if the MN has authorized it to do so by a
SoA AsyncInvite
command. The
inactive measuring system is requested by the MN over an
IdentRequest
service
for identification. The measuring system responses with an
IdentResponse
, a
special type of the
ASnd
frame. With reception of the
IdentResponse
the measuring
system is switched actively and can be accessed in the isochronous data
communication phase with a
PReq
frame.
Initially, in
NMT_CS_PRE_OPERATIONAL_1
status only a parameterization via Service
Data Objects is possible. However, it is possible to configure PDOs using SDOs.
NMT_CS_PRE_OPERATIONAL_2
With
a
SoC
frame
the
measuring
system
is
switched
into
NMT_CS_PRE_OPERATIONAL_2
. At first the measuring system waits until the
configuration is finished completely, then the node can be accessed with a
PReq
frame by
the MN. The measuring system responses with a “Dummy
PRes
”, which
contains no process data, the data are marked as invalid. No process data processing
is performed.
NMT_CS_READY_TO_OPERATE
With the NMT command
NMTEnableReadyToOperate
the measuring system is
switched into
NMT_CS_READY_TO_OPERATE
and signals its readiness to operation to
the MN. With the reception of a
PReq
frame by the MN the measuring system is
included into the cyclic data exchange.
Output process data (PReq frames) to the measuring system are already valid, sent
input data (PRes frames) to the MN are marked as invalid. The process data
correspond to the mapping configuration.
NMT_CS_OPERATIONAL
With the NMT state command
NMTStartNode
the measuring system is switched into
NMT_CS_OPERATIONAL
. This is the normal operating state of the measuring system.
Now, active process data exchange between MN and measuring system over
PReq
and
PRes
messages is possible. The process data correspond to the mapping
configuration.
