PSE

Incremental Shaft Encoders

Pliant Technology Specialists
Pliant : readily yielding to influence

Picture of the PSE-SDI


A PSE at work on the Gull River in Minden, Ontario

Interface Options

Standard Features

Shaft encoder water level sensors use a float and counterweight mounted to either end of a punched stainless steel tape. This tape engages a pulley which is mounted on the shaft of the sensor. These sensors are characterized by greater resolution than typical pressure transducers used for the same purpose.

PSE optical shaft encoders are intelligent sensors providing data through a communications port (SDI-12, MODBus RTU, ...) in engineering units using user-programmable OFFSET and SCALE (units per revolution) settings. Hardware includes a +10.5 to14V input for external battery, charger or solar panel and a 9 V alkaline battery to provide a total of approximately 240 hours of backup in the event of power supply interruption. The shaft is mounted on precision, zero-resistance bearings and is compatible to our pulleys.

Inquire about our pulleys and punched tapes which are Leupold & Stevens compatible!

The PSE shaft encoders also include a relay output which is controlled by user-programmable high and low levels. This output provides an ALARM control for conditions which typically correspond to drought and flood. The hysteresis for each of the trigger points is also user-programmable.

SDI-12 Interface: the "PSE-SDI"

The PSE-SDI provides a standard SDI-12 interface, version 1.3. SDI-12 commands allow the user to initiate a single sample of the water level or to calculate the average value based on a user-specified sampling period and number of samples.
The SDI-12 host is generally a data logger such as the PDAS-II but an interface between your PC and the shaft encoder is possible by ordering the PCOM-SDI.

MODBUS RTU Interface: the "PSE/RTU"

The PSE/RTU provides MODBUS registers that include the water level to 3 decimal places, OFFSET, Units per revolution (SCALE), Alarm trigger points. Distances of up to 4000' are supported between the PSE/RTU and the host using two twisted pairs (full duplex).

Modem-based Communications

The PSE shaft encoder can be equipped with a leased-line or dial-up modem. This allows practically unlimited distances between the sensor and the polling device.

The PSE/RTU/MDMLL provides a built-in leased-line modem. This must be purchased in conjunction with a Remote Terminal Unit (RTU) with Display and built-in leased-line modem (the PRTU/RTU/MDMLL). The PRTU/RTU/MDMLL polls the remote sensor at a fixed frequency of once per second. It then displays the real-time readings on an LED digital display and makes the data available to a MODBus host such as a SCADA or PLC, or an analog device using a 4-20mA loop (Option "/4-20").

The PSE/RTU/MDM provides a built-in dial-up modem. This must be purchased in conjunction with a Remote Terminal Unit (RTU) with Display and built-in dial-up modem (PRTU/RTU/MDM). The PRTU/RTU/MDM calls and polls the remote sensor at a fixed frequency. It then displays the real-time readings on an LED digital display and makes the data available to a MODBus host such as a SCADA or PLC, or an analog device using a 4-20mA loop (Option "/4-20").

"/4-20" Option: 4-20mA Output

The "/4-20" option provides a 4-20mA current loop output which is proportional to the current water level. The analog output makes use of a 16-bit DAC.
The water levels corresponding to an output of 4mA and 20mA are user-configurable from the digital display. Also, although the DAC is factory-calibrated, the unit features a calibration mode whereby 4mA and 20mA current levels are provided as a reference for fine adjustment of the device if necessary.


Note that the "/4-20" option must be purchased with the Digital Display option described below.

"/D" Option: Digital Display Interface

The PSE shaft encoders are available with a display and interface that allows the user to display as well as set up parameters without a host device. Therefore, in addition to the SDI-12, MODBUS or modem communications, the shaft encoder has two double-position switches and 8-digit display that can be used to view the current fluid level as well as set up the following parameters: the encoder SCALE and OFFSET, the device address and the ALARM trigger points.
Note that although the fluid level is readily accessible from the display, the setup parameters are in fact password-protected thus ensuring the integrity of your results.

Specifications

Processor : Atmel 89S8252 @ 3.6864 MHz.
Word Size : 8 bit data - 8 bit instruction
Memory : 89S8252, 256 bytes RAM
EEPROM 2 kbytes

Shaft Encoder

C-Model
Sensor type - two channel optical incremental encoder 100 x 4 counts per revolution
Resolution - 400 counts per revolution;
software conversion to engineering units provided in firmware. ( Units per revolution )

Range

+/- 30.7 meters with .375 meter circumference pulley
+/- 81.9 feet with 1.00 foot circumference pulley

Max. Response Speed

2.5 rev/sec.

Output

SDI-12 protocol

Power Supply

Configured for external 12 V lead-acid battery
9 V 565 mAHr alkaline battery backup
(Only if 9 pin connector is mounted)
 

Connectors

9 pin and 8 pin AMP CPC Connectors
Current Carrying Capability - 1.5 Amp rating
Dielectric Withstanding Voltage >1500V

Power Consumption

< 5 ma. quiescent current
maximum current : < 30 ma.

Mechanical Interface

Threaded shaft

1/4 x 32 thread; Float pulley mounts using three bolts in a non-conductive Delrin hub;
#303 stainless
A clamping assembly is available as an option.

Maximum safe load

10 lb (4.5 kg)

Starting Torque

0.65 inch-oz (47 cm-g) max.

Physical Characteristics

Height : 152.0 mm. (6.0 in.)
Width : 114.0 mm. (4.5 in.)
Depth : 70.0 mm. (2.75 in.)
Weight : 1.35 Kg (3.0 lb.)
Mounting : Four Mounting brackets, Standard height - 8mm. (0.31 in.)

Environmental Characteristics

Operating : -40 to +55 C
Storage : -60 to +100C
Humidity : <= 100% non-condensing
 


 

The above information is believed to be true at the time of printing. AMASS Data Technologies Inc. reserves the right to modify specifications without notice. All trademarks are owned by their respective companies.

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