9-36
ET 200U Distributed I/O Station
EWA 4NEB 812 6087–02b
Starting the Counter
The counter is reset and started by setting the SYNC bit in the diagnostics
byte during the reference point approach operation. The active pulses are
counted according to the rotation direction of the position encoder. The count
value is incremented during a positive count direction, and decremented dur-
ing a negative count direction.
Enabling the Outputs – Reaching the Setpoints – Resetting the Out-
puts
A positive pulse edge at the enable input enables the two outputs for switch-
ing.
An output and the associated diagnostics bit “setpoint reached” are set if all
of the following statements are true:
The position decoder was synchronized (SYNC bit = 1 and overflow
bit = 0).
The enable signal (terminal 3 on the terminal block) is set to 1.
The actual value corresponds to the selected setpoint.
The setpoint can be reached in the up–count or down–count direction.
ÉÉ
ÉÉ
ÉÉ
ÉÉ
ÉÉ
ÉÉ
Counter Status
Counting Pulses
Enable
Input
Output Q0 (Set–
point 1 Reached)
Output Q1 (Set–
point 2 Reached)
ÉÉ
ÉÉ
ÉÉ
ÉÉ
É
É
ÉÉ
ÉÉ
Measured Counting Pulse
Counter Is Still Disabled
0
1
2
3
4 5
6 7
8 9 10
–10 –9 –8 –7 –6
–4 –3 –2 –1 0 1
Up–Count Direction
SYNC Bit Is Set at the Start
Down–Count Direction
SYNC Bit Is Constantly Set
SYNC Bit (In
Diagnostics Byte
–5
Figure 9-21 Enabling the Outputs – Reaching the Setpoints – Resetting the Outputs
Function Modules
