Modbus RTU Digital I/O card


Thread Starter

Andrew Chiang

Can anyone tell me where to get a cheap Modbus RTU Digital I/O controller card (no need for additional configuration software) ? I just want to turn fan coil unit on/off using Modbus RTU protocol (for which we have our own software).

Andrew ST Chiang

Robert Dusza


Try Acromag at . They have some new MODBUS I/O Modules on the market. They are around $300 US. Will need the programming software
for them.

Good luck,


Robert J. Dusza, Jr.
Treatment Manager
(V) 1-860-647-3219
(F) 1-860-647-3150
E-mail - [email protected]
Manchester Water & Sewer Dept.
125 Spring St. P.O. Box 191
Manchester, CT 06045-0191
Try modules with Modbus protocol mfd by DGH CORPORATION USA.All utility software to set-up the module comes free with each shipment of DGH modules; if factory defualt settings are not suiatble.
For less than the cost of most of the other I/O modules you could use a Modicon Momentum Combo Base 170 ADM 350 10 (I think) and a low end Momentum PLC a 171 CCS 700 00. This would give 16 DIN and 16 DOUT for around $300. The PLC would need a configuration loaded in it but you may be able to get the distributor or someone else to load the configuration in its EEPROM so you wouldn't need Modsoft look for momentum.