mirror of
https://git.rwth-aachen.de/acs/public/villas/node/
synced 2025-03-16 00:00:02 +01:00
252 lines
6.1 KiB
C++
252 lines
6.1 KiB
C++
/** Timestamp hook.
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*
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* @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
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* @copyright 2014-2020, Institute for Automation of Complex Power Systems, EONERC
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* @license GNU General Public License (version 3)
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*
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* VILLASnode
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*********************************************************************************/
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/** @addtogroup hooks Hook functions
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* @{
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*/
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#include <villas/hook.hpp>
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#include <villas/timing.h>
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#include <villas/sample.h>
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#include <villas/log.h>
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namespace villas {
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namespace node {
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class TimeSync {
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protected:
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//Algorithms stability parameters
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//Examples from Paper:
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//const double p = 0.99;
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//const double k1 = 1.1;
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//const double k2 = 1.0;
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//Tuned parameters:
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const double p = 1.2;
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const double k1 = 1.3;
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const double k2 = 0.9;
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const double c = 0.7; // ~= mü_max
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const double tau = 1.; //Time between synchronizations
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//We assume no skew of our internal clock
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const double r = 1.;
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//Time estimate
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uint64_t x;
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//Skew correction
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double s;
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//Dampening Factor
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double y;
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public:
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TimeSync() : x(0), s(1.), y(0.)
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{
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//Check stability
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assert( tau < (p*(k2-p*(k1-k2)))/
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(c*(k1-p*(k1-k2))*(k1-p*(k1-k2))) );
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assert( 2*k1/3*p > k1-k2 );
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assert( k1-k2 > 0 );
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assert( 2 > p && p > 0 );
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}
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/** Returns the current time Error
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*
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* @actualTime The actual time from an external clock
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* @nanoseconds the nanoseconds since the last synchronization event
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*/
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int64_t timeError(const uint64_t actualTime, const uint64_t nanoseconds)
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{
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uint64_t currentEstimate = timeFromNanoseconds(nanoseconds);
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return (int64_t)actualTime + (int64_t)tau*1e9 - (int64_t)currentEstimate;
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}
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/** synchronizes with external clock
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*
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* @actualTime nanoseconds at which event should occur
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* @return nanoseconds estimate
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*/
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uint64_t synchronize(const uint64_t actualTime, const uint64_t nanoseconds)
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{
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double t_err;
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uint64_t ret;
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//Time estimate
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x = timeFromNanoseconds(nanoseconds);
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//Time Error
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t_err = ((int64_t)actualTime + (int64_t)tau*1e9 - (int64_t)x)/1e9;
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//Skew correction or internal frequency / external frequency
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s = s + k1*(t_err) - k2*y;
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//Dampening Factor
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y = p*(t_err) + (1-p)*y;
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//Clip skew correction
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if (s > 1.1) {
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s = 1.1;
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} else if (s < 0.9) {
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s = 0.9;
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}
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printf("time error: %f, x: %lu, s: %f, y: %f\n", t_err, x, s, y);
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ret = x;
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//If time estimate gets too large, reset x
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if ( x > tau*1e9) {
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x -= tau*1e9;
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}
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return ret;
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}
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uint64_t time(const double partOfFullSecond)
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{
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return x + partOfFullSecond*tau*r*s*1e9;
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}
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/** Returns time estimate based on the nanoseconds that passed since
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* last synchrsonization
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*
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* @return nanoesecond estimate
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*/
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uint64_t timeFromNanoseconds(const uint64_t n)
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{
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return time(n / 1.e9);
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}
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};
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class PpsTsHook : public Hook {
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protected:
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double lastValue;
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double thresh;
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double periodTime;//Period of sample frequency (Villas samples)
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unsigned idx;
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uint64_t lastSeqNr;
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unsigned edgeCounter;
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double pll_gain;
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timespec realTime;
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uint64_t last_sequence;
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double y;
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TimeSync ts;
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public:
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PpsTsHook(struct vpath *p, struct vnode *n, int fl, int prio, bool en = true) :
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Hook(p, n, fl, prio, en),
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lastValue(0),
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thresh(1.5),
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periodTime(1),
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idx(0),
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lastSeqNr(0),
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edgeCounter(0),
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pll_gain(1),
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realTime({ 0, 0 }),
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last_sequence(0),
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y(0),
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ts()
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{
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}
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virtual void parse(json_t *cfg)
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{
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int ret;
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json_error_t err;
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assert(state != State::STARTED);
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Hook::parse(cfg);
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ret = json_unpack_ex(cfg, &err, 0, "{ s: i, s?: f, s?: f}",
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"signal_index", &idx,
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"threshold", &thresh,
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"pll_gain", &pll_gain
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);
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if (ret)
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throw ConfigError(cfg, err, "node-config-hook-pps_ts");
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info("parsed config thresh=%f signal_index=%d", thresh, idx);
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state = State::PARSED;
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}
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virtual villas::node::Hook::Reason process(sample *smp)
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{
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assert(state == State::STARTED);
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/* Get value of PPS signal */
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float value = smp->data[idx].f; // TODO check if it is really float
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uint64_t seqNr = smp->sequence;
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/* Detect Edge */
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bool isEdge = lastValue < thresh && value > thresh;
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lastValue = value;
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double timeErr;
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double changeVal;
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static const double targetVal = 0.5;
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auto now = time_now();
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realTime.tv_nsec = ts.timeFromNanoseconds(now.tv_nsec);
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if (realTime.tv_nsec >= 1e9) {
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realTime.tv_sec++;
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realTime.tv_nsec -= 1e9;
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}
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if (isEdge) {
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edgeCounter++;
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currentNanoseconds = now.tv_nsec;
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ts.synchronize(0.5e9, currentNanoseconds);
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}
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if(isEdge){
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info("Edge detected: seq=%lu, realTime.nsec=%lu, timeErr=%f , timePeriod=%f, changeVal=%f", seqNr,realTime.tv_nsec, timeErr, periodTime, changeVal);
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}
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if (edgeCounter < 2)
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return Hook::Reason::SKIP_SAMPLE;
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/* Update timestamp */
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smp->ts.origin = realTime;
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smp->flags |= (int) SampleFlags::HAS_TS_ORIGIN;
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if((smp->sequence - last_sequence) > 1 )
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warning("Samples missed: %li sampled missed", smp->sequence - last_sequence);
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last_sequence = smp->sequence;
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return Hook::Reason::OK;
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}
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~PpsTsHook(){
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}
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};
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/* Register hook */
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static char n[] = "pps_ts";
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static char d[] = "Timestamp samples based GPS PPS signal";
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static HookPlugin<PpsTsHook, n, d, (int) Hook::Flags::NODE_READ | (int) Hook::Flags::NODE_WRITE | (int) Hook::Flags::PATH> p;
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} /* namespace node */
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} /* namespace villas */
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/** @} */
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