RoCon ® Series 6
Electronic rotational speed change sensor
How it Operates
A self-contained sensor is employed to sense blades on a target rotor mounted on the driven shaft.
The unit operates on a digital principle, the response time being inversely proportional to speed, i.e the higher the speed the shorter the response time.
Switching occurs when the frequency of the blades passing the sensor corresponds to the threshold frequency. On dropping below the threshold the sensor de-activates.
Standard Units
Allows a machine to 'run up to speed'. If normal running speed is not achieved within 10 seconds the sensor switching current is interrupted.
Pre-set to activate at the min speed of 0.8 rev/min. Adjustable on site. (On request, units can be supplied to activate at a specified speed.)
DSEAR/ATEX
The RoCon® Series 6 complies fully with the Dangerous Substances and Explosive Atmospheres Regulations 2002 and the requirements of Category 2 & 3 Equipment. It is suitable for use in Zone 21 & 22 conditions.
Approval
Sensor Design
The RoCon can be wired into the starter circuit of the control system, or used to give an input directly to a PLC.
The sensor provides an open circuit when de-energised operating from a 24 to 240V AC/DC 50 Hz supply.
For maximum safe operation wiring into the starter circuit is to be preferred as the RoCon is still functional if manual operation of the system can bypass the PLC control.
Connection to the sensor is two wire. Sensor Part Order No. 0048/3048
Sensor Specification
- Supply: 24-240 Volts AC/DC
- Fusing: Supply to be fused at 5A max
- Switching Capacity: 200mA max
- Saturation Voltage: 8 Volts Max. (Output On)
- Ambient Temperature: -15 to +50 ºC
- Output State: Normally closed above set speed
- Normally open below set speed
- Input Pulse Range: 10-3600 ppm
- Maximum Voltage Drop (closed): 8 Volts
- Maximum Leakage Current (open): 1.6mA
- Minimum Switching Current: 5mA
- Hysteresis: 1% typically
- Sensor Enclosure: ISO threaded 30mm by 1.5 pitch, PET/PEN co-polymer.
- Sensor Protection: IP65 Relative Humidity: 90% RH
- Red Input LED: Target sensed
- Coloured Output LED:
- Green: Normal Status
- Orange: Programming not accepted, unit has defaulted back to default setting and requires re-programming.
- Red: Sensor needs re-calibrating, follow recalibration procedure.
- Connections: 2 wire lead. See wiring diagram.
Typical Wiring Diagrams:
Directly Connected into Starter Circuits
Standard Units With Time Delay
The RoCon is wired in series with the stop push button and when operated the RoCon conducts for 10 seconds to allow the machine to run up to speed. After 10 seconds the machine rotation maintains the RoCon in a conducting state. If the machine’s speed drops below the switching speed the RoCon will cease conducting thus releasing the machine starter.
NOTE: The start up delay is initialised when the sensor is powered up from an open circuit condition.
Units Without Time Delay
Units are normally used with relays, timers and PLCs in automatic control circuits. Relay connection to the RoCon will energise when the machine reads the pre-set speed and will release in event of underspeed. RoCon can also be used to detect overspeed and a typical circuit shown.
WARNING: If the starter coil current is greater than 200mA, an interposing relay MUST be used or damage to the sensor will occur
RoCon Units For PLC Applications
Start-Up Delay
Most installations require machines to run up to speed and the standard RoCon (ref: 045/2080/01) has a 10 second delay to allow for this process. If the delay is to be programmed into the PLC then the version of the RoCon without an inbuilt delay (ref: 045/2080/11) should be used.
Interfacing with the PLC (and miniature relays)
AC circuits
The two wire sensor in the RoCon is directly applicable to AC input devices and relays provided the 5mA sensor switching current is exceeded and a leakage current of greater than 3mA does not inhibit the OFF state.
When leakage current causes a problem a 'Reactive Load Module' can be provided for wiring in parallel with the load. This unit is a Watt-less device that adds to the total load, but generates almost no heat. it is therefore preferable to ballast resistors and can be used where multiple devices are wired in close proximity.
DC circuits
For 24 Vdc circuits and less, a 1k Ohm, 1.5 Watt 'bleed' resistor should be wired in parallel with the load according to the diagram below. On request a suitable resistor can be provided free of charge.
Safety Information
- The electric cable must NOT be used to retain the rotation of the unit. The aluminium strap must be secured to the back of the unit with the bolt provided, and locked against a suitably secure structure.
- Any work on electrical parts may only be undertaken by suitably competent person, observing the relevant electrical safety regulations.
- The fixing bolt into the shaft MUST be tightly fitted. A standard 19mm A/F spanner should be used to tighten the unit onto the shaft.
- Unit must be installed in accordance with the design drawings of the plant and the installation drawings included with the unit.
- Do not apply any external loads to the unit when fitted.
- Injury may result from opening the unit whilst live or whilst in operation.
Features and Benefits
- MULTIVOLTAGE Operation
- Speed range of 0.4 to 720 rev/min
- The Security and Protection of both machinery and system in the event of a machine failure.
- Protection to IP657 BSEN 60529
- Speed change detection unit Detecting - Mechanical failure, Overspeeding, Underspeeding
- Supplied ready to fit
- Self-contained
- On-site adjustable speed switching
- Low cost installation
- Compatibility with PLC systems
Typical Applications
Rotation / no rotation detection of a shaft
In the event of machine failure the RoCon provides a control signal to stop and protect the machine. Used within single or multiple machine control systems.
Sequence interlocking at start-up
Ensures each machine in series is running before the preceding machine starts.
Automatic emergency shut down
The emergency stopping of one machine fitted with RoCon is signalled enabling preceding machines to be stopped so preventing a cumulative breakdown.
Variations and Optional Extras (a - d)
Without start-up delay
For use with relays, timers and PLC’s in automatic control circuits.
Low speed range
Used in conjunction with a ten-bladed sensor target, a selectable speed range of 0.4 to 50 rev/min is available.
Pre-set switching speed units
These units can be supplied to activate at any speed within the range.
- Foot mounting bracket
- Junction box
- Shaft connection guard
- Inspection test certificate
Unit Housing and Enclosure
The housing is moulded from corrosion resistant glass reinforced polyester resin. Colour Orange.
Enclosure protection is to IP657 to BSEN 60529 - temperature range -25 to +70°C and complies with temperature class T6 to BS 4683 and IEC 79.8.
Special units for hazardous areas
These units can be supplied for use with a client’s approved speed monitor to form an 'Intrinsically Safe System'. The technical details provided on this page would therefore Not Apply.
Please contact us for more details.
Sensor Adjustment & Recalibration
The sensor start-up delay and speed activation threshold can be adjusted on-site as follows:
- Start up machine and allow time for it to attain normal running speed.
- The sensor has two LEDs for information purposes, the input LED is red and flashes every time rotor passes the front face of the sensor. The output LED is tri-colour. Under normal conditions the output LED is green, under fault conditions the LED may br orange or red. See the specification table for fault codes.
- Whilst the magnet is placed against the target the output LED will flash at one second intervals, as a guide to the time delay. When the magnet is removed, the output LED will again flash at one second intervals, to confirm the start-up delay and at the same time the unit will self-calibrate to 20% under the monitored speed.
- If zero start-up delay required, allow the machine to reach running speed, then touch the target with the magnet and instantly remove.
Important Safety Information
Caution:
Danger from rotating internal parts
Danger from electric shock when live.
These instructions must be read prior to installation of the RoCon unit. Only suitably competent and authorised personnel should attempt to install or maintain this unit.
RoCon control units are an integrated part of the safety concept for the prevention of accidents worked out for our machines and plants.
Shipping / Packing Specification
- Net weight 1.1kg, gross weight 1.4kg
- Carton size 210 x 170 x 160mm
(approx. 4.2mb)