Torque dump controllers

Axon manufacture two styles of controller that can be used to stop a piece of equipment when a user set value is reached.

These units were devised for use initially on large rotary torque machines such as are shown in the stroking torque machine section of this site.

STC 6000

Features

The simplest controller, shown below here is the STC 6000 unit which is based around a standard DIN mounted display.

The The unit operates with five-digit resolution and a dummy 6th digit can be supplied for machines reading over 99,999-ft lbs. The display can be calibrated in one of two modes either 0-99,999 ft lbs. or 10 to 999,990 ft lbs.

Display resolution is 1 ft lb. from 0-99,999 and 10 ft lb. when set up for greater than 99,999. The display can be set to use either two point simple straight-line calibration or a corrected 24-point calibration.

The controller has three controls. The way it is set for dump control is that the Run/Set switch is turned to the set position. The display now reads the value current set for torque shut down. Turning the 10 turn dial will alter this value. Once the display is reading the desired set value then the run/set switch is returned to the run position. The reset trip button is pressed and the system is primed and ready to run. The operator then increases the torque on the joint and when it reaches the set torque the dump valve will be fired and will stay off until the reset button is pressed again. If on pressing reset the torque is still above the set torque the valve will trip again.

The dump control requires no other calibration or set up, and uses the calibration of the display. The dump control is designed to be fast and does not rely on the reading update rate of the display for trip operation. The display has a configurable peak display function which may be used to store the maximum torque read during the torque operation.

The STC 6000 has a flexible dump valve drive capability. It can be factory configured to provide both normally powered or normally off supply for the dump valve, and can also be set to supply 110 or 240 volts AC power to the valve, and also 12 or 24 volts DC. These settings are factory configured although they can be changed in the field if required. The STC 6000 operates using 100 or 240 volts AC power, which is fed into the unit using a sealed connector on the rear of the unit.

The STC unit is panel mounted and being relatively light requires nothing other than the four front panel screws to secure it. There is a cover to allow access to the internals of the unit, which can be removed once it is pulled from the panel. The STC 6000 requires a panel cut out of 185X126 mm, and requires clearance of 290 mm at the rear.

The front panel is powder painted with a lacquer finish, for scratch free operation. The unit is sealed to IP55, and should be kept out of direct rainfall, or excessive dust.

There are two basic options for sensing the torque applied (or any parameter you wish). The first is using a load cell. The device is only designed for a single load cell. It will cope with a load cell, which reverses direction, and using the linearisation function can have a corrected calibration for forward and reverse. A pressure transducer can also be used to measure applied torque. The dump control only operates with a single transducer. If corrected readings for breakout are required this would have to be done by creating a second "scale" on the display unit. This would allow the unit to have different calibration in breakout than makeup.