EAU-321 Multi Protocol Serial Port Card

By connecting port 3 (AutoFieldBus) to an external GPRS DTU or serial server via RS232, maintenance engineers can monitor the device status on the fieldbus in real-time on a remote computer, perform fault location or firmware upgrades, without the need to physically visit the site.

Troubleshooting and maintenance recommendations

Common problems and troubleshooting steps

Problem 1: Port 1/2 cannot communicate, but port 3/4 is normal

Check if the J5/J6 jumper settings are consistent with the required protocol

Confirm that the communication parameters (9600/8/N/1) of the third-party device match

Check the polarity of cable connections: RS422 requires T+to be connected to the other party R+, T - to be connected to the other party R -; RS485 requires A to be connected to A, B to be connected to B

For RS485 mode, ensure that there is at least one terminal resistor (approximately 120 Ω) on the bus at both ends

Problem 2: Redundant AutoCom does not switch

Confirm that both ports are connected to the target device

Check if the physical link of the backup port is intact when the primary port fails

Verify that the redundancy mode in the AutoSafe system software is enabled

Check if power fluctuations cause the board to reset

Question 3: AUTROLON download failed (port 4)

Confirm that the current panel is the 'Startup Panel' in a distributed system

Check if the serial cable from PC to port 4 is a crossover cable (or using a straight through cable with adapter)

Attempt to reduce the baud rate (although the specification is 9600, the download tool may support other rates)

Confirm that no other software is occupying the COM port

Problem 4: The system cannot detect EAU-321

Check if the PC/104 bus stack connection is secure and if there are any bent pins

Verify if the J7 address jumper is both A/B In (address 100h)

Confirm that the system units have not exceeded the limit of the number of communication boards (with/without batteries)

Measure whether the+5V power supply is within the range of 4.5V-5.5V

Question 5: Intermittent data errors

For RS422/RS485 long-distance lines, check if the shielding layer is single ended grounded

Check if the RS232 cable length exceeds 15 meters

Eliminate strong electromagnetic interference sources (such as frequency converters, high-power wireless transmitters)

Attempt to reduce communication speed (but AutoSafe is fixed at 9600, and third-party devices also need to be adjusted accordingly)

Maintenance Recommendations

EAU-321 uses solid-state circuits with no moving parts, theoretically requiring very low maintenance. However, considering that it is installed inside the fire alarm control panel, it is recommended to check during the annual system testing:

There is no dust accumulation or corrosion marks on the surface of the board

All jumper caps are not loose or oxidized

The terminal block screws are tightened without looseness or copper plating

PC/104 stacked connector without oxidation

The power supply voltage is stable within the range of+5V ± 5%

If there is a suspected hardware malfunction, on-site repair is not recommended. Autronica technical support should be contacted and spare parts should be replaced. The short-circuit protection design of EAU-321 makes it less susceptible to permanent damage due to wiring errors, but repeated overvoltage may damage the ESD protection diode.