Efficient Networks Siemens Sinamics S120 - Manual (Page 249)

Function modules
7.8 Closed-loop position control
Drive Functions
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
249
● p2546 LR dynamic following error monitoring tolerance
● p2547 LR cam switching position 1
● p2548 LR cam switching position 2
● p2551 BI: LR setpoint message present
● p2554 BI: LR travel command message active
● r2563 CO: LR latest following error
● r2683.8 Actual position value <= cam switching position 1
● r2683.9 Actual position value <= cam switching position 2
● r2684 CO/BO: EPOS status word 2
7.8.5 Measuring probe evaluation and reference mark search
Description
The "Reference mark search" and "Measuring probe evaluation" functions can be initiated
and carried-out via binector input p2508 (activate reference mark search) and p2509
(activate measuring probe evaluation). Binector inputs p2510 (measurement probe selection)
and p2511 (measurement probe edge evaluation) define the mode for measurement probe
evaluation.
The probe signals are recorded via the encoder encoder status and control word. To speed
up signal processing, direct measuring probe evaluation can be activated by selecting the
input terminals for probes 1/2 via p2517 and p2518. Measuring probe evaluation is carried
out in the position controller cycle, whereby the set send clock cycle of the controller
(r2064[1]) must be an integer multiple of the position controller cycle (p0115[4]).
The system outputs a message if the same probe input is already being used (see also
p0488, p0489, p0580, and p0680).
The appropriate function is started using a 0/1 edge at the appropriate input p2508 (activate
reference mark search) or p2509 (activate measuring probe evaluation) via the encoder
control word. Status bit r2526.1 (reference function) signals that the function is active
(feedback from the encoder status word). Status bit r2526.2 (measurement value valid)
shows the presence of the measurement required r2523 (position for reference mark or
measurement probe).
Once the function is complete (position determined for reference mark or measurement
probe), r2526.1 (reference function active) and r2526.2 (measurement valid) continue to
remain active and the measurement is provided by r2523 (reference measurement) until the
corresponding input p2508 (activate reference mark searches) or p2509 (activate
measurement probe evaluation) is reset (0 signal).
If the function (reference mark search or measuring probe evaluation) has still not been
completed and the corresponding input p2508 or p2509 is reset, then the function is
interrupted via the encoder control word and status bit r2526.1 (reference function active) is
reset via the encoder status word.
If both binector inputs p2508 and p2509 are simultaneously set, this causes the active
function to be interrupted and no function is started. This is indicated using alarm A07495
"reference function interrupted" and remains until the signals at the binector inputs are reset.