What is BRAIN instruments?

BRAIN=Broadcast Rapid Access Intelligent Network

The BRAIN communication protocol or Smart field devices was Yokogawa’s implementation or version of the frequency modulation method. Like HART, it superimposes a frequency over a 4 to 20 mA signal in order to transmit digital data…A 0 is represented by a 2400 Hz frequency and a 1 with a null frequency. So the baud rate is 1200 bps. It requires a BRAIN loop resistance of 250 Ohms and is what you’d call a sort of Japanese HART. Since it is a proprietary protocol, it didn’t had the widespread acceptance of HART. A similar history to Foxboro’s Foxcomm protocol.

Yokogawa still sells the BT200 a BRAIN compatible handheld, and even has a BRAIN Comm DTM to make possible the use of FDT frameworks for BRAIN devices setup and configuration

In order to configure a BRAIN device, you’ll need a BRAIN handheld communicator like the Yokogawa BT200. Otherwise you can use a BRAIN modem. Yokogawa has a USB modem that is compatible both with HART devices and BRAIN devices. But in that case you’ll need a PC with the Fieldmate device configuration software. As far as I know Yokogawa has both BRAIN and HART versions of its field devices. Although the communication concept is the same the protocol is different.