UDP Encoder Interface (rix Mono Encoder)

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 usage

$ 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

tprtrig

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

tprtrig

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

encoder_0 log file

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 output

$ 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

Recording Experiment rixlx9720 Run 262

This was the first recording of the encoder using interface version 2.0.0.