Ams trex™ Device Communicator

3.17
Polling options for HART devices
The Field Communicator application uses the HART polling options to search for
connected devices. By default, the Trex unit searches for a device at address zero and
automatically connects to the device, if it is detected. Most HART device installations
contain one device per HART loop and the device address is zero. Multidrop mode is
enabled by changing the address from zero to any address between 1 and 63. See the
device documentation for more information about changing a device address.
If the Trex unit cannot find the device at address zero, the device connection wizard
displays a message asking if you want to change the polling option.
The Trex unit can poll by:
•
Address - Select an address (0-63).
•
Tag - Enter the tag of the device.
•
Long Tag - Enter the long tag of the device.
Note
If the Trex unit polls addresses greater than 15 on a loop with HART Universal Revision 5
devices, those devices may appear at multiple addresses.
Note
If you have two devices on a HART loop and one device is at address zero, disable the 
Auto-
Connect
option in the Trex Settings. Otherwise, the Trex unit automatically connects to
the device at address zero and does not detect the second device.
3.17.1
Set the polling options for HART devices
When you connect to a device, the Trex unit by default automatically polls address zero
and connects to the device at that address. If the Trex unit does not find a device at
address zero, you are prompted to change the polling address in the device connection
wizard.
If you change the polling option, the selected option is not saved. You need to select the
desired option each time you connect to a device.
Note
If you have two devices on a HART loop and one device is at address zero, disable the 
Auto-
Connect
option in the Trex Settings. Otherwise, the Trex unit automatically connects to
the device at address zero and does not detect the second device.
Procedure
1. Connect the lead set to the Trex unit and to the device.
2. Open the Field Communicator application.
3. If the Trex unit does not automatically connect to the device, tap 
HART
.
4. Follow the prompts to connect to the device.
Field Communicator application
User Guide
September 2021
98
User Guide

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5. Tap 
Yes
when prompted if you want to change the polling option.
6. Select a polling option at the top of the screen.