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RC SYSTEMS
PRODUCTS |
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ST-60A ANALOG TO MODBUS RS-485 CONVERTER
- Accepts analog voltage or current inputs and transmits RS-485 data to a Modbus® Master device.
- The protocol is Modbus® RTU; supporting function codes 2 through 6.
- As many as 128 ST-60A converters may be multidropped onto the same twisted pair data highway.
- Transmitted data includes the analog value scaled for range & engineering units, discrete HIGH - WARN & FAULT alarm values, and a 16 character identification descriptor.
- Requires 12 or 24 VDC power.
- Available in general purpose high density DIN rail mount housing or an explosion-proof instrument enclosure suitable for Class 1, Groups B,C,D; Class 2, Groups E,F,G. Also meets NEMA 4 with included 'O' ring.
- Modbus compatible alarm controllers and displays are also available from R. C. Systems Co. Inc.
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The Model ST-60A is an analog to RS-485 Modbus® protocol converter. It accepts a voltage or current inputs and scales the signal into the appropriate range. Six engineering unit and sixteen channel identification characters may also be transmitted. In addition, HIGH, WARN & FAULT discrete alarm values are available. ST-60A’s are easily configured using a PC or a special hand held battery powered programmer. 128 ST-60A’s may be connected to the same twisted pair cable.
A primary advantage over traditional 4-20mA loops is much more information is available with Modbus®. When a receiver device accepts a 4-20mA signal, it does not receive the range, engineering units, location, or if a level alarm exists. All of this must be programmed into the receiver for each input. However, when a Modbus® master receiver device accepts data from an ST-60A, it simply displays the results. No determination must be made concerning alarms, range or location. Another advantage is that ST-60A wiring may be daisy chained with as many as 128 units on the same run of cable. Traditional analog systems require home runs containing at least 2 wires per signal.
A Modbus® master is required to interrogate ST-60’s. R. C. Systems Co. manufactures a complete family of controllers capable of operating as masters. Other examples of Modbus® masters are PC’s, DCS’s and PLC’s which may be equipped with Modbus® software drivers. ST-60A’s are packaged in high density DIN rail mount enclosures. Non-Volatile RAM retains all configuration data indefinitely.
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