Routine:        Chk3    
Function:       Checks that minimum motor speed < maximum motor speed
Called by:      Range   
Calls:          Error
Entry:          Mtrmin, Mtrmax have been set by Chk1 and Chk2
Exit:           C flag is set on error
Preserved:      None


CHK3    LD      A,(MTRMAX)
        LD      B,A
        LD      A,(MTRMIN)
        SUB     A,8
; Make sure that the difference between the maximum and minimum motor speeds is positive and greater than 8.
        CP      B
        JR      Z,CHK3A
        JR      C,CHK3A
        RET
CHK3A   LD      A,5
; Signal an error if the range is too small or the minimum speed greater than the maximum speed.
        CALL    ERROR
        SCF     
        RET