FRSA-00 ABB RS-485 Adapter Board for ACS350 Modbus-RTU Drives

FRSA-00 | ABB RS-485 Adapter Board for ACS350 Modbus-RTU

The FRSA-00 is an RS-485 adapter board from ABB. It adds a two-wire Modbus-RTU link to the ACS350 drive family. The board carries a built-in 120 ohm termination resistor. It works alongside the FMBA-01 Modbus RTU adapter module. The link is asynchronous, half-duplex RS-485. Top speed is 115.2 kb/s. Use shielded twisted pair cable with 100 to 150 ohm impedance. The board fits trunk-line networks with short drop lines. Engineers pick it for legacy ACS350 panels that need a simple serial fieldbus connection.

Serial Link Characteristics

• Physical layer: two-wire RS-485 with signal ground.
• Mode: asynchronous, half-duplex, multipoint.
• Protocol: Modbus-RTU.
• Topology: trunk line; drop lines allowed.
• Cable: shielded twisted pair, 100 to 150 ohms.
• Termination: 120 ohms, built into the FRSA board.
• Max transfer rate: 115.2 kb/s.
• Bus bias: applied voltage between -7 V and +12 V DC.

Grounding and Bus Integrity

• Tie the RS-485 signal ground of every node to one common potential.
• Long runs can build large ground voltage differences.
• Ground offset plus data swing must stay inside the bus window.
• Excess offset can drop data or damage the port.
• Follow TSB89, Application Guidelines for TIA-EIA-485-A.

Technical Data

• Model: FRSA-00
• Brand: ABB
• Type: RS-485 adapter board
• Protocol support: Modbus-RTU
• Partner module: FMBA-01 Modbus RTU adapter
• Drive family: ACS350
• Max speed: 115.2 kb/s
• Termination: 120 ohms, on board

Shipping, Warranty and Stock

• We dispatch in 24-28 hours.
• Shipment runs through FedEx, UPS and DHL.
• Every board carries a 12-month warranty.
• We verify each unit before it leaves.
• Ask us for current stock and lead time.

FAQ

Q: Does the FRSA-00 include the 120 ohm resistor?
A: Yes. The termination is built into the board. You still need a resistor at the far end of the trunk if that node has none.

Q: Can I mix FRSA-00 and FMBA-01 on one network?
A: Yes. Both support two-wire RS-485 Modbus-RTU. Set the same baud rate and parity on every node.

Q: My bus drops data on long cable runs. What should I check?
A: Measure the ground potential difference between nodes first. Add a signal ground wire and check termination. Keep the pair away from VFD output cables.

Q: Which cable should I buy for an ACS350 network?
A: Use shielded twisted pair with 100 to 150 ohm impedance. Belden 3105A or similar works well. Ground the shield at one end.

Q: Is FRSA-00 still the right choice for a new build?
A: For ACS350 panels already on Modbus, yes. For new designs, send us the drive model and we will confirm the best serial or fieldbus option.