Hart Communication/Response Time Impact In A Dp Network - Honeywell Experion PKS User Manual

7 DEVICE SUPPORT BLOCK (DSB)
Under the DPV1 Data Records, configure the following:
9
In the Data Type (DPV1DATATYPE) list, select the data type as required from the list of supported
a
data types for each Parameter Name (DPV1PARAMNAME).
In the Value (DPV1PARAMVALUE) box, type the parameter value for writing or monitoring the DPV1
b
parameter value.
c In the Parameter Name (DPV1PARAMNAME) box, type the parameter name.
In the Byte Offset (DPV1BYTEOFFSET) box, type the byte offset value of the parameter, which needs
d
to be mapped from the DPV1 response.
In the Bit Offset (DPV1BITOFFSET) box, type the bit offset value of the parameter, which needs to
e
mapped from the DPV1 response.
10 Click OK.

7.2.2 HART communication/response time impact in a DP network

The following factors can impact the DPV1/ HOP scan time in a DP network.
HART devices that are distributed per slave
If there are more number of HART devices configured in a single slave, then PGM takes more time to complete
HOP scan than the slaves that contains less number of HART devices. This is because the DPV1 command for
each HART device needs to be sent only after the previous command response is received.
DP Network baud rate
DP Network baud rate has direct impact on any communication on the DP network. If the baud rate is high, then
the time taken to receive the response is less. Similarly, if the baud rate is less, then the time taken to receive the
response is more. In addition, if the baud rate is high, then more commands can be sent in allocated DPV1
bandwidth. If baud rate is low, then less number of command in the allocated DPV1 bandwidth.
Allocated DPV1 Bandwidth
The DPV1 requests are sent in a single cycle based on the configured DPV1 BANDWIDTH parameter value,
and hence DPV1BANDWIDTH value has direct impact on the scan time of DPV1 requests.
Slaves capability
Some of the slaves has the capability to serve more than one DPV1 request at a time and some of the slaves
supports only one request at a time.
Field Device Manager (FDM) requests
If the FDM is connected to the DP network and communicates to the devices that are configured, then the FDM
takes priority than the HOP and DPV1 requests. Therefore, the FDM requests also has a direct impact on the
HART communication.
Configured DPV1 Requests
The number of DPV1 requests that are configured for each slave and the priorities also have an impact on the
HART command response time-out since both the DPV1 and HOP requests are serviced.
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Attention
The Octet string data type is not supported.
Attention
This parameter is available for configuration only when the data type is configured as "Boolean."