SN65LBC179 for multipoint communication on RS485 bus.

Erwan Coton

Other Parts Discussed in Thread: SN65LBC179

For a new design I use the part SN65LBC179 for RS485 communication with one master and six slaves.

The communication is OK when there is one master and one slave but when I add one slave on the bus I loss the communication.

I see that the signal Z (pin 6 on the part for the slave) is collapsed, so the difference between Y and Z is less than 2V.

My question is : THe part SN65LBC179, is it OK for communication RS485 with mulitipoint ?

0 Thomas Kugelstadt over 12 years ago

For multi-point communication you need to have the capability to turn driver and receiver off.

You cannot do this with the LBC179. I recommend it therefore for poit-to-point links.

Are you open to other suggestions?

Do you use a half- or full-duplex bus?

What's the data rate requires?

We have several hundreds of devices. I'm sure we can find one fitting your application needs.

Regards, Thomas

0 Erwan Coton over 12 years ago in reply to Thomas Kugelstadt

Thank you Thomas.

I use full duplex bus 4 wires. I undestand that I need to disable other receiver.

What part could you propose ?

I use on my board SO8 footprint and I have to keep 4 wires. datarate = 38400 bauds.

Regards,

Erwan

0 Thomas Kugelstadt over 12 years ago in reply to Erwan Coton

Erwan,

I'm sorry for the late response. I was still on vacation.

The device I suggest is the SN65HVD3080 (see data sheet attached).

more modern design providing less power consumption and a more robust design.

let me know how it goes.

best regards, Thomas

sn65hvd3080e.pdf

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