"Polling Address 0" Appears On My YHC5150X?

Polling Address 0

If a HART™ device is connected to a YHC5150X communicator but "Polling Address 0" appears on the screen or the device is not in the table of found devices, follow these steps:

1. Make sure all connections are correct and secure.
2. Check for shorts, open circuits, and multiple grounds. 
3. Determine if the loop resistance is greater than 250 ohms and less than 1100 ohms. If less than 250 ohms, then use the supplied 250 ohms load resistor in series with the loop. (see graphic below)
4. Determine if any device is in "burst mode". Disable burst mode if possible during troubleshooting.
5. Check the polling address type and range selected from the system menus. If the polling address set on the transmitter is outside the range selected for the communicator, it cannot discover the device.
6. If multiple HART devices are in the loop, there could be an address conflict (two devices with the same address). Testing the devices individually is the best procedure.
7. Determine if there are multiple master devices on the loop. HART communication only permits one primary and one secondary master.
8. Remove all other secondary master devices from the loop for troubleshooting.

Wiring Diagram: Loop resistance < 250 ohms

For low loop resistance (less the 250 ohms), a 250 ohm resistor may be needed in the loop to ensure reliable HART communication. Yokogawa supplies a 250 ohm resistor in the form of a shunt resistor built into the standard wiring adapter.