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Application Article
Spinal Decompression Device utilizes 2 Smart-PAK PLUS ePLCs
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Controller used - Smart-PAK PLUS (1 as master, 1 as slave)
Total Digital Inputs - 16
Total Digital Outputs - 12
Total Analog Inputs - 10 @ 0-10 VDC
Total Analog Outputs - 2 @ 0-10 VDC
Communication Protocol - ModBus RTU
Operator Interface - Computer via Graphical User Interface, interfaced via RS232 ASCII
Our customer is utilizing two Smart-PAK PLUS ePLCs for their application. The controllers are networked in a Master / Slave configuration, utilizing Entertron's ModBus RTU protocol. In addition, one of the RS232 serial ports is configured for Entertron's ASCII protocol and interfacing directly to a command computer for control by the doctor. The Smart-PAK PLUS can be ordered with a MODASCII protocol, combining ModBus and ASCII. The protocol is determined through an internal relay in the ladder program for each serial port.
The spinal decompression device treatment procedure combines spinal extension of the lumbar spine with traction from the patient's body weight. The device was first designed to relieve a patient's chronic lower back pain and degenerative disc disease. Now, the device is also used as an exceptional stretching apparatus to increase flexibility, spinal mobilization and improve posture for athletes.
The digital inputs are used for switches to control the device, independent of the computer. The patient / customer can operate the table via the hand grip buttons. This feature enables our customer to market their device to fitness and training centers. The additional digital inputs are tied to an 8 switch remote that allows the operator to control the machine manually.
Three of the digital outputs are interfaced to relays to control motor starters. Nine are interfaced to solenoids and control the table movement through hydraulics.
The Smart-PAK PLUS controls all movement of the table. The 8 analog inputs are interfaced to potentiometers to provide multiple axis position control of the table. In addition to movement, 2 analog inputs, are interfaced to two load cells for the patient's body weight.
The two analog outputs are used to display the values of the load cells to the operator / doctor.
The two Smart-PAK PLUS controllers are networked via ModBus RTU. Specific registers are utilized for transmitting and receiving data from the master and slave. Two controllers were required due to the amount of analog required for their application.
The table is set up with three preprogrammed routines. Custom routines can be created and stored by patient name in the computer.
