Overview
Data Format 1.0.0
At each trigger, the UDP Encoder sends one header structure followed by up to eight channel structures.
See the definitions of encoder_header_t and encoder_channel_t in github: UdpEncoder.hh
Zach writes:
...we’re currently taking the PLC’s internal encoder numerator, which is a floating point number less than zero, multiplying it by 10^6, and sending it as an integer. So, the “unit” of the output is baked into the protocol.
Data Format 2.0.0 🆕
Version 2.0.0 of encoder_channel_t adds a uint16_t field 'scaleDenom.' If nonzero, it is the denominator of a rational scale value.
'encoderValue' (shape: 1): 23563414
'timing' (shape: 1): 505870
'scale' (shape: 1): 1
'scaleDenom' (shape: 1): 150
'mode' (shape: 1): 0
'error' (shape: 1): 0
'majorVersion' (shape: 1): 2
'minorVersion' (shape: 1): 0
'microVersion' (shape: 1): 0
Zach writes:
...if the denominator is used, we do no pre or post multiplication of the values. If I need to express something like numerator = 1.16 and denominator = 5.0, I would send 116 and 500 which maintains the same ratio as the original.
In the specific case of this encoder, I send 1 and 150 exactly and your code on the other side simply doesn’t do the *1e-6 step because a denominator is present.
Testing With Encoder Simulator (sim_udpencoder)
To test with the simulator, run sim_udpencoder on the same host as drp_udpencoder and use the matching "-p <partition>" setting. The simulator sends packets to drp_udpencoder via localhost (127.0.0.1).
$ sim_udpencoder -h Usage: sim_udpencoder [options] Options: -r <rate> (0:929kHz,1:71kHz,..) -e <evcode> -p <partition> -d <data port> (default 5006) -v (verbose) Either -r or -e or -p is required
Send SIGUSR1 to the sim_udpecoder process to simulate a dropped UDP packet.
$ kill -USR1 pid
Send SIGUSR2 to the sim_udpecoder process to simulate 4 consecutive dropped UDP packets.
$ kill -USR2 pid
Testing With Loopback Mode (drp_udpencoder -L <loopback_port>)
Configuring TPR On DAQ Partition
You can get tprtrig to trigger the EVR on a DAQ partition, then sleep, like so:
$ tprtrig -t a -c 0 -o 1 -d 2 -w 10 -p 4 -z
programs EVR /dev/tpra (-t a) to generate a TTL trigger using logic channel 0 (-c 0) on output 0 (-o 1 [bit mask]) with delay of 2 119MHz clocks (-d 2) and width 10 119 MHz clocks (-w 10) for every L1Accept on partition 4 (-p 4).
Configuring TPR Standalone
Generate 1Hz triggers on output 0 with a width of 54 nanoseconds, then sleep.
$ tprtrig -t a -c 0 -o 1 -d 1 -w 10 -r 6 -z
Loopback Mode
In loopback mode no encoder or PLC or added process is required, as drp_udpencoder sends and receives simulated data via localhost.
Run drp_udpencoder with the -L <loopback_port> flag to enable loopback mode. For example, "-L 5007" loops back on localhost port 5007.
Monitoring UDP packets with netcat
-bash-4.2$ hostname drp-neh-cmp015 -bash-4.2$ nc -lvu 192.168.0.8 5006 Ncat: Version 7.50 ( https://nmap.org/ncat ) Ncat: Listening on 192.168.0.8:5006 Ncat: Connection from 192.168.0.3. 'plc-tst-proto6w? ?bdSimEncoder (plc-tst-proto6Q? ?zdSimEncoder )plc-tst-proto6+g ??dSimEncoder *plc-tst-proto6 ??dSimEncoder +plc-tst-proto6 ??dSimEncoder^C -bash-4.2$
Updates to rix.cnf file
$ diff rix.cnf rix.cnf.ENCODER
67a68,69
> { host: 'drp-neh-ctl002', id:'tprtrig', flags:'sp', cmd:'tprtrig -t a -c 0 -o 1 -d 2 -w 10 -z'},
> { host: 'drp-neh-cmp015', id:'encoder_0', flags:'spu', rtprio:50, cmd:f'drp_udpencoder -l 0x8 -o {data_dir} -P {hutch} -d /dev/datadev_0 -C {collect_host}'},
Recording Experiment rixdaq18 Run 23
rix-drp_udpencoder[70415]: <I> UDP receiver thread started rix-drp_udpencoder[70415]: <I> setting lane 0 rix-drp_udpencoder[70415]: <I> PGPReader saw Configure transition @ 985133577.575584342 (0004674c799500) rix-drp_udpencoder[70415]: <I> EbReceiver saw Configure transition @ 985133577.575584342 (0004674c799500) rix-drp_udpencoder[70415]: <I> received key = beginrun Opening file /ffb01/data/rix/rixdaq18/xtc/rixdaq18-r0023-s002-c000.xtc2 rix-drp_udpencoder[70415]: <I> Opening file '/ffb01/data/rix/rixdaq18/xtc/rixdaq18-r0023-s002-c000.xtc2' rix-drp_udpencoder[70415]: <I> Opening file '/ffb01/data/rix/rixdaq18/xtc/smalldata/rixdaq18-r0023-s002-c000.smd.xtc2' rix-drp_udpencoder[70415]: <I> PGPReader saw BeginRun transition @ 985133590.653839154 (0004674d32e3bd) rix-drp_udpencoder[70415]: <I> EbReceiver saw BeginRun transition @ 985133590.653839154 (0004674d32e3bd) rix-drp_udpencoder[70415]: <I> received key = beginstep rix-drp_udpencoder[70415]: <I> PGPReader saw BeginStep transition @ 985133595.531025432 (0004674d77fa30) rix-drp_udpencoder[70415]: <I> EbReceiver saw BeginStep transition @ 985133595.531025432 (0004674d77fa30) rix-drp_udpencoder[70415]: <I> received key = enable rix-drp_udpencoder[70415]: <I> PGPReader saw Enable transition @ 985133600.224320451 (0004674dba80e8) rix-drp_udpencoder[70415]: <I> EbReceiver saw Enable transition @ 985133600.224320451 (0004674dba80e8) rix-drp_udpencoder[70415]: <I> received key = disable rix-drp_udpencoder[70415]: <I> PGPReader saw Disable transition @ 985133613.263120215 (0004674e7336db) rix-drp_udpencoder[70415]: <I> EbReceiver saw Disable transition @ 985133613.263120215 (0004674e7336db) rix-drp_udpencoder[70415]: <I> received key = endstep rix-drp_udpencoder[70415]: <I> PGPReader saw EndStep transition @ 985133613.268625231 (0004674e734afa) rix-drp_udpencoder[70415]: <I> EbReceiver saw EndStep transition @ 985133613.268625231 (0004674e734afa) rix-drp_udpencoder[70415]: <I> received key = endrun rix-drp_udpencoder[70415]: <I> PGPReader saw EndRun transition @ 985133613.326952707 (0004674e742027) rix-drp_udpencoder[70415]: <I> EbReceiver saw EndRun transition @ 985133613.326952707 (0004674e742027) rix-drp_udpencoder[70415]: <I> received key = unconfigure rix-drp_udpencoder[70415]: <I> PGPReader saw Unconfigure transition @ 985133630.918879608 (0004674f6d5f9b) rix-drp_udpencoder[70415]: <I> EbReceiver saw Unconfigure transition @ 985133630.918879608 (0004674f6d5f9b)
Recording Experiment rixdaq18 Run 27
This was the first recording of the encoder at 120Hz.
$ xtcreader -d -w 1 -f /cds/data/psdm/rix/rixdaq18/xtc/rixdaq18-r0027-s000-c000.xtc2 | grep shape | head -16 'encoderValue' (shape: 1): 23563414 'timing' (shape: 1): 505870 'scale' (shape: 1): 6667 'mode' (shape: 1): 0 'error' (shape: 1): 0 'majorVersion' (shape: 1): 1 'minorVersion' (shape: 1): 0 'microVersion' (shape: 1): 0 'encoderValue' (shape: 1): 23563404 'timing' (shape: 1): 838450 'scale' (shape: 1): 6667 'mode' (shape: 1): 0 'error' (shape: 1): 0 'majorVersion' (shape: 1): 1 'minorVersion' (shape: 1): 0 'microVersion' (shape: 1): 0
Viewing Encoder Value in AMI
