Termination resistor for iEM3255

[AkihiroY]

Hello Community,

 I plan to instll PAS600L and serveral iEM3255 for our customer.

Communciation btw the devices will be done on Modbus RTU. If my understanding correct, when we connect the devices using RS485, we also need to care the termination resistor for the both end of the wiring.

I found that PAS has the functionality to prevent reflection and enabled it as a default. (URL)
Then, I still could not find the description about the requirement for termination resistor in the iEM3255 manual.
Is there any recommendation for it? Or don't we need care that for this device?

# In case of PM5300, I could find the descrption which request to use 120 ohm resistor.(Attached)
I could not similar description for iEM3255.

[Charles_Murison · Accepted solution]

Hello @AkihiroY ,

The size of the terminating register depends on the impedance of the cable used. 100-120 ohm is common.

Regards,

Charles