Chapter 6 - Heartbeat Protocol; Chapter 7 - Process Data Objects - Honeywell DPS CANopen User's & Technical Manual

Digital Pressure Sensor with CANopen

CHAPTER 6 - HEARTBEAT PROTOCOL

The NMT master will use the heartbeat message produced by
the Digital Pressure Sensor with CANopen
determine that the node is present on the network. The Model
DPS will send a heartbeat message every n mS, where n is
the heartbeat producer time available at object 0x1017. If the
heartbeat producer time is zero then no heartbeat message will
be transmitted. Table 15 depicts the Heartbeat message. The
default heartbeat producer time for the Digital Pressure Sensor
with CANopen , Model DPS, is zero.
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6.1 Heartbeat Message
Table 15. Digital Pressure Sensor with CANopen
Heartbeat Message
COB-ID(hex)
0x700+Node-ID
Where state can have any of the following values
Table 16. Heartbeat Protocol States
COB-ID(hex)
0
4
5
7F
12 sensing.honeywell.com
, Model DPS, to
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Byte 0
State
Byte 0
Boot-up
Stopped
Operational
Pre-operational
, Model DPS
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CHAPTER 7 - PROCESS DATA OBJECTS

The real-time process data transfer is performed by means of
process data objects (PDO). Upon entering the operational
state, the Digital Pressure Sensor with CANopen
starts transmitting the pressure in 32 bit signed integer format
at an update rate of 100 millisecs.
7.1 PDO Transmission Type
The transmission type parameter of a PDO specifies the
transmission mode (synchronous, event driven) as well as the
triggering mode.
Transmission modes:
• Synchronous
• Event-driven
Synchronous
For synchronous PDOs, the transmission type also speci-
fies the transmission rate in the form of a factor based on the
basic SYNC object transmission period. A transmission type
of 0 means that the message shall be transmitted after occur-
rence of the SYNC (acyclic – not periodically), only if an event
occurred before the SYNC. The transmission type 1 means
that the message shall be transmitted with every SYNC object
(cyclic). A transmission type of n means that the message shall
be transmitted with every n-th SYNC object.
Event-driven
Event-driven TPDOs are transmitted without any relation to the
SYNC object.
Triggering modes
In the Digital Pressure Sensors with CANopen
two message-triggering modes are distinguished:
• Event-driven
• Synchronously triggered
Event- and timer-driven
Message transmission is either triggered by the occurrence of
an application-specific event specified in manufacturer-specific
profile or if a specified time (event-time) has elapsed without
occurrence of an event.
Synchronously triggered
Message transmission is triggered by the occurrence of the
SYNC object. The trigger condition is the number of sync and
optionally an internal event. The Model DPS supports the trans-
mission types listed in the Table 17.
50085804, Rev. B
, Model DPS,
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, Model DPS,
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