Specifications

Functional Overview
ProLinx Communication Gateways, Inc. 12
HART Master Protocol Drive Manual
August 17, 2004
Poll Cmd 0
with addresses
1 to 15
Multidrop
Read and store
configuration
for a device
Poll each device
found for data
with CMD 3
P<X
P++
P>=X
C<Y
P=0, next device, if at past
end of device list, C++ &
1
st
device
C>=Y
No device
Device(s) Found
C=0, P=0, 1
st
device
*
Start
Communication
failure on all
devices
* - If user commands are ready to execute,
issue them at this time.
X = Poll counter value set in #define
HART_POLL_COUNTER.
Y = Configuration counter set in #define
HART_CONFIG_COUNTER.
In multidrop mode, the channel will poll for instruments 1 to the value set in the MAX
DEVICE COUNT parameter. For each device found, it will continuously poll for data
using command 3. After a certain number of iterations, the HART Driver will ready the
configuration data for the next device (if there is one). Each time configuration
information is acquired, it will be for a different slave device if more than 1 slave is
recognized by the channel. Less frequently, the channel will poll for devices not found in
the original search of the network using HART command 0. If communications is lost
with all devices, the module will try to establish communications with the devices using
command 0. If user commands are present and enabled, they will be executed after the
data polling of the devices.
Multidrop Mode Example
:
The intent is to show when using Multidrop mode how the Auto-Poll DB Address and Max
Device Count parameters should be used.
If the configuration file sets the following parameters:
Parameter Value Config File Section
DB Address Status 3660
Auto-Poll DB Address
400
Max Device Count 15
[HART PORT 0]
DB Address Status 3661
Auto-Poll DB Address 1200
Max Device Count 15
[HART PORT 1]
DB Address Status 3662
Where
P, C = loop iterators
X = Poll Counter (internal fixed value)
Y = HART configure counter (internal fixed value)