Control Network Newsletter
Solutions for Expanding the Number of I/O Points in the Field
July 2014 - Contemporary Controls now offers BACnet MS/TP and Modbus RTU input and output modules to provide a convenient way for expanding the number of I/O points in the field. These modules, called "Cube I/O", are compact, cost-effective modules available with analog and digital inputs and outputs in varying combinations.
In a MS/TP application, if the controller is short a few I/O points, the Cube I/O is an easy addition. Wire the module to the MS/TP communication cable, use the existing 24 VAC power (assuming your other devices are half-wave rectified) and discover the points as standard objects via a BACnet client. You are now ready to build on your application.
Need some retentive inputs for counting utility pulses (gas, water, air, electricity) but your controller is not retentive, or cannot support an accumulator function, or has no free input points - no problem. Use the BMT-SI4 (4 independent points) accumulating pulses at a rate of 16 pulses per second. Expand the scope of the project with minimal additional expense.
The analog MS/TP and Modbus RTU input modules both support 10K type 3 thermistors, 0 to 10 VDC, and in addition Balco 500 RTD and PT and NI sensors. Cube analog input module provides support for a comprehensive variety of sensors for those applications requiring standard and specialty sensors.
Planning on using the BASgatewayLX to convert some Modbus data to BACnet/IP instances? If you need to pick up some additional points, either input or outputs the Cube I/O can be added to the BASgatewayLX and the head end BACnet/IP controller can read and write the added Cube I/O in addition to obtaining the data from the Modbus device(s). Need to add some retentive pulse accumulators? Use the Modbus RTU MR-SI4 to get the job done.
Use the Cube I/O with the BASremote. Need to add some I/O but don't need the flexibility of the universal inputs and outputs of the BASremote expansion module. Plan to use the appropriate Cube module(s) connected to the Modbus port of the BASremote. You can even power up the Cube I/O from the BASremote Auxiliary Power Output terminals. Clean and simple.
The BACnet MS/TP and Modbus RTU Cube I/O modules offer the following module combinations:
- 4 or 10 point input module
- 4 point retentive pulse input module
- 8 point analog input module
- 4 point relay output module
- 4 point analog output module
- 4 point input and 2 relay output module
Modules have the following operational specifications:
- operates at 20 to 28 V AC /DC
- selectable baud rate of 9,600 to 115,200 for both MS/TP and Modbus RTU
- 2 wire RS485 communications
- operating temperature of -5 to 55 Degree C
- DIN rail mounted
- LED's for bus activity, error indication and I/O status
- polarity reversal protection
- small size
The modules are designed to minimize wiring. If multiple Cube I/O modules are used in an installation each module can be jumped to the module next to it, and then the next module jumped to the next and so on. This provides a quick and clean installation. All power and communications are jumped between the modules. In fact the Cube line offers a 24 VDC power supply that can be the head end of a chain of jumped Cube I/O.
To learn more, visit the Cube I/O product page.
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