SQO [Sequencer Output] Rockwell Software
Use the SQO instruction with the SQC instruction to transfer 16-bit data to word addresses for the control of sequential machine operations.
On successive false-to-true transitions, the SQO instruction moves a step through the programmed sequencer file, transferring step data through a mask to a destination word. The done bit is set when the last word of the sequencer file is transferred. On the next false-to-true transition, the instruction resets the position to step one.
You may use indexed or indirect addressing to represent addresses in this instruction.
You can use the reset (RES) instruction to reset a sequencer. All control bits (except FD) will be reset to zero. The position will also be reset to zero. Program the address of your control register in the RES.
Entering Parameters
File is the address of the sequencer file. Make sure to use the file indicator (#). This file stores the reference data for monitoring inputs.
Mask is a hexadecimal code or the address of the mask word or file through which the instruction moves data. If the mask is a file, its length will be equal to the length of the sequencer file. The two files track automatically.
You can enter the code in binary, decimal, or hexadecimal. RSLogix500 will make any necessary conversion and display the hexadecimal value. Click here for an example showing how to enter the Mask value using hexadecimal, binary, or decimal values.
Destination is the address of the output word or file for a SQO to which the instruction moves data from its sequencer file.
Control is the instruction’s address and control element (3 words) that stores the status byte of the instruction, the length of the file, and the position in the file. Do not use this address for any other instruction.
Status bits in the control file include:
11 = ER (error bit)
13 = DN (done bit)
15 = EN (enable bit)
The control element:
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Word 0 EN DN ER
Word 1 Length of sequencer file
Word 2 Position
Length is the number of steps of the sequencer file starting at position 1. Maximum = 255 words (104 words when using the MicroLogix controller). Position 0 is the startup position. The instruction resets (wraps) to position 1 at each cycle completion. For example, placing a 6 in this parameter means 6 elements beyond the starting address (total of 7 elements). A length value that points past the end of the programmed file causes a runtime major error to occur.
Position is the word location or step in the sequencer file from/to which the instruction moves data. A position value that points past the end of the programmed file causes a runtime major error to occur.
