More Info
The SRI chute height sensor measures the height of bagasse in a Donnelly chute above the mill, and is typically used in the control system for the flow of bagasse through a sugarcane crushing mill or, for the first mill, to control speed of the prepared cane feed elevator.
The height is measured via stainless steel electrodes installed in the chute wall. By measuring conductivity to determine the presence of material at each electrode, chute height control is an important regulating component that evens out bagasse flow through the mill.
Clients benefit from reduced energy usage and lower risk of mechanical failure as a result of the more consistent mill feed, improving productivity through higher extraction rates for mills with good chute height control.
Technical Features
Microprocessor technology measures the conductivity of material surrounding each electrode. The SRI chute height sensor determines the number of electrodes covered and updates the current output which is ramped to provide a pseudo analogue output. A number of detection algorithms allow the elimination of false sensing.
The SRI chute height system has the flexibility of being able to measure one chute with up to 16 electrodes, or two chutes with up to 8 electrodes in each chute. When operating in dual chute mode, two 4-20 mA analogue output signals are provided.
As well as analogue outputs, single pole single throw (SPST) relay outputs are provided for high/low level alarms or chute height indicator lights independent of the mill control system.
Commissioning
Most mills install and commission their SRI chute height sensors without external assistance. However we can provide commissioning assistance to help with configuration and calibration if preferred by clients.
Ongoing support
The SRI chute height sensor is a toughened product, designed to sustain the harsh environment typical of a sugar mill and provide many years of trouble-free service. In addition free support is provided by email, phone and fax for the life of the product.
In the unlikely event of breakdown, SRI also provides a “return to base” repair service. For further details, or to organise a repair please contact your nearest global representative or SRI direct.
Specifications
Absolute maximum ratings
| Supply voltage input: | 28 VDC |
| Voltage on sensor inputs: | 50 VDC |
| Voltage on current outputs: | 36 VDC |
| Relay contact current: | 2 A |
Recommended operating conditions
| Input supply voltage: | 24 VDC |
| Input supply voltage ripple: | max. 0.1 V |
| Power supply rating: | 15 W |
| Ambient temperature: | 20-30 °C |
| Ambient humidity: | 45-65%RH |
Electrode interface and conductivity detector
| Cable length to electrodes: | max. 25 metres |
| Detection signal frequency: | 1.92 kHz |
| Detection signal amplitude: | 5 Vpk-pk |
| Threshold adjustment limits: | max. 5 Vpk-pk |
| Sensor scan rate: | 24 Hz |
| Detection signal source impedance: | 360-50 kΩ |
| Sensitivity adjustment range: | 50 kΩ |
| Bagasse moisture content: | min. 45% |
Supply
| Operating supply voltage range: | 20-26 VDC |
| Ripple and noise at input: | max. 0.2 V |
| Supply current at 24 VDC: | 0.05-0.4 A |
| Voltage protection: clamping voltage: | 31-45 VDC |
| Self-resetting fuse break current at 20: | 1.8 A |
| Self-resetting fuse hold current at 20: | 0.9 A |
Analogue outputs
| Source voltage: | 24 VDC |
| Load resistance: | 0-1000 Ω (250 Ω typical) |
| Limits of zero (4 mA) adjustment: | 3.3-4.9 mA |
| Limits of full scale (20 mA) adjustment: | 19-22 mA |
Relay outputs
| Rated contact current: | max. 2 A |
| Rated contact power: | max. 60 W |
| Rated contact voltage (AC): | max. 24 VAC |
| Rated contact voltage (DC): | max. 30 VDC |
Environmental conditions
| Storage temperature range: | 0-70 °C |
| Operating temperature range: | 5-50 °C |
| Ambient humidity: | 20-70%RH |
| Vibration (10-60 Hz): | max. 0.02 G |
| Shock: | Not permissible |
Physical characteristics
| Dimensions: | 210 x 90 x 60 (mm) |
| Protection Rating: | IP00 |
| Material: | Polycarbonate |
| Mounting: | 35 mm DIN |
| Weight (approximate): | 0.3 kg |
AC power
| Output voltage: | 24 VDC |
| Output voltage tolerance: | 10% |
| Rated output current (no temp. derating): | min. 1 A |
| Output ripple at full load: | max. 0.2 VDC |