BECKHOFF KL2521-0000 - Manual (Page 17)

Access from the user program
KL2521 15
Control and Status Byte
Control Byte in process data exchange
The Control Byte is sent to the terminal from the controller. It can be used
in register mode (REG = 1) or in process data exchange (REG = 0).
Bit 7 6 5 4 3 2 1 0
Name Reg_Access 0 Cnt_Clr 0 0 Go_Counter Ramp_Dis Freq_Sel
Bit Name Function
7 Reg_Access 0: Register communication inactive (process data exchange)
5 Cnt_Clr The contents of the counter is cleared or set (Feature.10) by this
bit. Any overflow or underflow bits that might be set are also
cleared by this bit. The process can be edge triggered or level
triggered (Feature.4).
2 Go_Counter If travel distance control is active (Feature.9), then a pre-set
counter value is approached when the bit is set
1 Ramp_DisS Operation of the ramp function is cancelled, in spite of Feature.5
being active; if travel distance control is active, it is interrupted by
this bit
0 Freq_Sel Rapid change of the base frequency
(only if the ramp function is inactive)
0: Base frequency 1 (registers 36 / 37)
1: Base frequency 2 (registers 38 / 39)
Status Byte in process data exchange
The Status Byte is sent from the module to the controller.
Bit 7 6 5 4 3 2 1 0
Name Reg_Access Error Input_Z Input_T Overflow Underflow Ramp_Active
Sel_Ack/
End_Counter
Bit Name Function
7 Reg_Access 0: acknowledge for process data exchange
6 Error General error bit, included with overflow/underflow
5 Input_Z End position reached
4 Input_T The actual value when the device is connected does not agree
with the set value of the connected device.
3 Overflow This bit is set if the 16-bit counter overflows (65535 -> 0). It is
reset when the counter exceeds one third of its measuring range
(21845 -> 21846) or immediately an underflow occurs.
2 Underflow This bit is set if the 16-bit counter underflows (0 -> 65535). It is
reset when the counter drops below two thirds of its measuring
range (43690 -> 43689) or immediately an overflow occurs.
1 Ramp_Active Ramp is currently being followed
0 Sel_Ack/
End_Counter
Confirms the change of base frequency.
At
activated travel distance control:
target counter value reached
The change of the base frequency needs a reset for activation.