FS24X/FS20X DTM Manual, Issue 1
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It may be necessary to DISCONNECT the Communication DTM and then CONNECT again
to successful establish communications.
• The HART polling address set in the device is not the same as set in the device DTM.
For details, see §4.1.2
• The device is connected to a HART Multiplexer and the Multiplexer configuration is not
prepared for this device. In most cases, the HART Multiplexer has to be triggered to
recognize the device at one of its loops. It does not scan loops the time. Many HART-
Multiplexer require the polling address of the device to the 0. For changing the address
of your device to 0, see §4.1.2
• The FSX-014
4.1.2 Setting HART polling address
The HART Technology is capable to connect more than one HART device to a single 4-20mA
loop. This is called multidrop-mode.
The identification of a HART device is done via its polling address. The valid range is 0-63,
while 0 is a special case:
Only for address 0, the loop current will be influenced by measuring and alarm of the
device, for any other address it stays at 4mA, independent of measuring or alarm. In-
fluencing the current also requires the device to be the only HART device in the loop.
Device and DTM must be set to the same polling address, and no other device attached to
this loop shall use this address. Using an address twice will lead to a broken HART commu-
nication for one or more devices.
In many cases multidrop-mode is not in use, and the address is “0”. This is the default address
of the DTMs.
Note:
The FSX-A014 (FS24X/FS20X) device does only support polling addresses between 0
and 15. Setting any higher address will lead to a broken communication that can’t be
set back via the DTM anymore.
4.1.2.1 Setting the polling address of a HART device
• Add the HART Commication DTM to your environment, if not already done.
• Set „End address“ to a higher value, e.g. „5“
• Adjust the COM-Port settings to get access to your HART-Modem (see §4.1.1)
• Establish a connection to the COM-Port: right click on the HART Communication DTM
and choose “Connect”. The “two plug”-Icon will change and now the plugs are con-
nected and green.
• Again, right click on the HART Communication DTM an choose “Additional func-
tions/Change device address”
• While opening the view, the HART bus is scanned for devices within the address range
between “start address” and “end address”: The result may look like this
• Here, a device is found at address “0”
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