Setup Software
Installation
Operation
& Specifications
Manual
620-0018 R1.1 © Microfl ex 2016, 2017
101-0029
MicroLinK HM
RS-232 HART Protocol Modem
HART Device to Modbus Accumulator
DIN Rail Mount
The MicroLink-HM 101-0029 is an RS-232 to HART® protocol modem with managed HART master timing to
function as either a primary or secondary HART master - eliminating the need for external CD monitoring and RTS
control. It can also be used as a HART to Modbus Concentrator polling up to 16 HART devices. Power can be taken
from the serial port DTR handshake line or an external 5 to 30 volts DC power supply.
When used as a HART protocol modem it provides the hardware interface between Highway Addressable Remote
Transducer devices (HART) and a computer with an RS-232 port. Unlike many HART modems, communications
direction control is handled internally so there is no need to handle tricky request-to-send (RTS) handshake timing,
greatly simplifying software development and enabling the MicroLink-HM modem to be compatible with common
USB to RS-232 serial converters. Serial port baud rates can be set from 1200 to 57,600 and parity can be odd, even,
or none. HART protocol communications between the MicroLink-HM and HART devices is always 1200 baud, odd
parity.
MicroLink-HM can be confi gured to poll up to 16 HART devices and save the HART device data into modbus reg-
isters. Modbus RTU commands can then be used to read the HART device data. Confi guration is simple using the
included MicroLink-HM Confi guration software. Settings are saved in modus registers so modbus RTU commands
can also be used to edit the MicroLink settings. No special confi guration cable is needed for setup as communica-
tions is done using the MicroLink-HM serial port.
