|The BSL command loads data into a bit array one bit at a time. The data is shifted through the array, then unloaded one bit at a time. An example for the use of this instruction might be for tracking bottles through a bottling line where each bottle constitutes a bit.|
The BSL command is an output instruction that loads data into a bit array one bit at a time. When the rung goes from false to true, the enable bit (EN bit 15) is set and the data block is shifted to the right (to a lower bit number) one bit position.The specified bit at the bit address is shifted into the last bit position. The first bit is shifted out of the array and stored in the unload bit (UL bit 10) in the status byte of the control element. The shift is completed immediately.This command is equivalent to the BSR command except for the fact that the designated register shifts in the opposite direction.
The following procedures occur when True.
The wraparound operation is completed when the position of the bit address is equal to the last bit of the array or to the UL bit, whichever applies.
Several parameters must be set when programming this instruction. A definition and explanation is given below for each parameter.
Develop a process using the BSL command.
An example of the BSL process is given along with the ladder logic. The enable bit , operated by sensor #2 (see figure below), loads a bit into the register sequetially. Sensor #1 (see figure below) labels the bit that is loaded with a high or low signal corresponding to the contents of the bottle. If the bottle is full, a high signal is stored in the shift register while a low signal is stored in the shift register if the bottle is empty. The Process Illustration shows an example of this process where the shift register, shown below the illustration, corresponds with the volume of fluid in the bottles. The enable bit then loads, labels, and stores more bits corresponding with the assembly line. An example of this ongoing process is shown in the Process Assembly Line illustrated below. The order of ongoing shifts are labeled from the left to the right in numerical order. The empty bottle "low signal" can be observed moving towards the ejector during the sequence of shifts. At the time when the empty bottle "low signal" reaches the output sensor, a low signal registers in the ejector bit. This low signal is passed through the ejector bit switch shown in the ladder logic and a single pulse is generated that triggers the ejector and ejects the bottle.