Configuration and operation
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integrated sensors. The option is active by default. It can be deactivated by setting the
CJC
parameter to
Off
.
4.9 NTP protocol
The module supports the synchronization of the RTC with an NTP server v4. Open the
NTP
group to config-
ure NTP parameters.
Table 4.8. NTP parameters
Parameter
Description
Range
Default
value
Access
Enable
Enable NTP connection
On
/
Off
Off
RW
NTP server pool
IP or URL of NTP pool. If the server is located
in an external network, check the correct val-
ues for the parameters
Gateway
and
DNS
(
Network
group)
-
pool.ntp.org
RW
NTP server 1
IP or URL of the primary NTP server
-
192.168.1.1
RW
NTP server 2
IP or URL of the secondary NTP server
192.168.1.2
RW
Synchronization
period
Time synchronization period in seconds.
Ensure the set value is not less than the mini-
mum value for the selected NTP server.
5…65535 s
5
RW
Status
Server connection status
-
-
R
All specified NTP servers (including servers from the pool) have the same polling priority.
For more information see document:
4.10 MQTT protocol
4.10.1 Basics
The MQTT protocol defines two types of network entities: a message
broker
and a number of clients. Broker
is a server that receives all messages from the clients and then routes the messages to the appropriate des-
tination clients. Client can be
publisher
or / and
subscriber
.
Published messages are organized in a hierarchy of
topics
. When a publisher has a new data to distribute, it
sends a message with the data under the particular topic to the connected broker. The broker distributes the
message to any clients that have subscribed to that topic.
A topic is a UTF-8 encoded character string that the broker uses to filter messages for each connected cli-
ent. The topic consists of one or more topic
levels
. Each topic level is separated by a forward slash (topic
level separator).
When a client subscribes to a topic, it can subscribe to the exact topic of a published message or it can use
wildcards to subscribe to multiple topics simultaneously. There are two kinds of wildcard symbols:
single-
level
(+) and
multi-level
(#) (see Example 2).
4.10.2 Implementation
The module supports the MQTT protocol (v3.1.1) and can be used as client. It can publish information about
the status of its inputs and outputs and can be subscribed to topics which control its outputs.
To configure the MQTT parameters, open the
MQTT
group in the parameter tree.
NOTE
When using the MQTT protocol, it is recommended to set the parameter "Safe state
timeout" (“Modbus Slave” group) to 0, since writing is usually event-driven and not cyclic
in this case.
