I am trying with the interactive version of pymodbus (pip install pymodbus[repl]) to access a modbus device (UPS).
I had accessed it by using mbpoll tool, so the communication and device are both working.
I guess I am having problems to figure out what are the "right" parameters that match the equivalent mbpoll.
From documentation, I am trying to access the values starting at 30405 (page 864 liebert-intellislot-modbus-rtu-reference-guide-SL-28170_0.pdf) what I understand as holding registers as the function is 30xxx:
pg 864 - Vertiv™ | Liebert® IntelliSlot Modbus/BACnet Reference Guide
Table 3.118 Liebert® GXT5—Input and Holding (continued)
Data Label Input Holding # of Reg Scale Notes/Units
System Input Frequency 30405 — 1 10 Uint16
System Input Power Factor L1 30406 — 1 100 Uint16
System Input Power Factor L2 30407 — 1 100 Uint16
System Input Power Factor L3 30408 — 1 100 Uint16
System Input Max Voltage L1-N 30409 — 1 10 Uint16
System Input Min Voltage L1-N 30410 — 1 10 Uint16
System Input Max Voltage L2-N 30411 — 1 10 Uint16
System Input Min Voltage L2-N 30412 — 1 10 Uint16
System Input Max Voltage L3-N 30413 — 1 10 Uint16
Using the mbpool it returns values as expected:
mbpoll -r 396 -t 3 -c 125 -1 -q 192.168.160.1 | \grep -v "65535 (-1)"
-- Polling slave 1...
[396]: 2162
[402]: 7
[405]: 599
[406]: 53
[409]: 2279
[410]: 2048
[415]: 230
[416]: 27
[417]: 60
[418]: 1
[419]: 0
[420]: 190
[431]: 2163
[434]: 599
[435]: 230
[446]: 2
[447]: 0
[448]: 1
[449]: 0
[450]: 1
[451]: 0
[452]: 14446
...
Then I fired /usr/local/bin/pymodbus.console tcp --host 192.168.160.1 --port 502 and at prompt I've tried several combinations of client.read_holding_registers only to get the "message": "IllegalAddress" for all trials below (and others, varying count, unit, addresses, etc):
client.read_holding_registers address=30396 count=10 unit=1
client.read_holding_registers address=396 count=10 unit=1
client.read_holding_registers address=30396 count=10 unit=0
client.read_holding_registers address=396 count=10 unit=0
The complete return of one of theses client.read is:
> client.read_holding_registers address=396 count=10 unit=0
{
"original_function_code": "3 (0x3)",
"error_function_code": "131 (0x83)",
"exception code": 2,
"message": "IllegalAddress"
}
Since it is returning valid values from mbpoll, I suspect I am doing something wrong with the parameters of client.read_holding_registers, but I can't figure out where is the problem.
Both access are from the same machine, at the same time, running opensuse tumbleweed.
Accessing as root or normal user does not make any difference.
I appreciate any hints to deal with the register address with pymodbus module.
As per the comments the mbpoll command line options can cause some confusion:
-t 3:int16 16-bit input register data type with signed int display
-t 4 16-bit output (holding) register data type (default)
This is confusing because the modbus command to read an input register is 4 and for holding registers its 3 (so the reverse of the mbpoll arguments). This is mentioned in an issue.
So the command you need will be client.read_input_registers address=395 count=10 (as per the comments there is also an issue with register numbering - the "Modbus: When 40001 Really Means 1, or 0 Really Means 1 " section in this article explains this well).
Related
I'm looking for a method to generate a good seed for generating different series of random numbers in processes that starts at the same time.
I would like to avoid using one of the math or crypto libraries because I'm picking random numbers very frequently and my cpu resources are very limited.
I found few example for setting seeds. I tested them using the following method:
short program that picks 100 random numbers out of 5000 options. So each value has 2% chance to be selected.
run this program 100 times, so in theory, in a truly random environment, all possible values should be picked at least once.
count the number of values that were not selected at all.
This is the perl code I used. In each test I opt in only one method for generating seed:
#!/usr/bin/perl
#$seed=5432;
#$seed=(time ^ $$);
#$seed=($$ ^ unpack "%L*", `ps axww | gzip -f`);
$seed=(time ^ $$ ^ unpack "%L*", `ps axww | gzip -f`);
srand ($seed);
for ($i=0 ; $i< 100; $i++) {
printf ("%03d \n", rand (5000)+1000);
}
I ran the program 100 time and counted the values NOT selected using:
# run the program 100 times
for i in `seq 0 99`; do /tmp/rand_test.pl ; done > /tmp/list.txt
# test 1000 values (out of 5000). It should be good-enough representation.
for i in `seq 1000 1999`; do echo -n "$i "; grep -c $i /tmp/list.txt; done | grep " 0" | wc -l
The table shows the result of the tests (Lower value is better):
count Seed generation method
114 default - the line: "srand ($seed);" is commented ou
986 constant seed (5432)
122 time ^ $$
125 $$ ^ unpack "%L*", `ps axww | gzip -f`
163 time ^ $$ ^ unpack "%L*", `ps axww | gzip -f`
The constant seed method showed 986 or 1000 values not selected. In other words, only 1.4% of the possible values were selected. This is close enough to the 2% that was expected.
However, I expected that the last option that was recommended in few places, would be significantly better than the default.
Is there any better method to generate a seed for each of the processes?
I'm picking random numbers very frequently and my cpu resources are very limited.
You're worrying before you even have made a measurement.
Is there any better method to generate a seed for each of the processes?
Yes. You have to leave user space which is prone to manipulation. Simply use Crypt::URandom.
It is safe for any purpose, including fetching a seed.
It will use the kernel CSPRNG for each operating system (see source code) and hence avoid the problems shown in the article above.
It does not suffer from the documented rand weakness.
Don't generate a seed. Let Perl do it for you. Don't call srand (or call it without a parameter if you do).
Quote srand,
If srand is not called explicitly, it is called implicitly without a parameter at the first use of the rand operator
and
When called with a parameter, srand uses that for the seed; otherwise it (semi-)randomly chooses a seed.
It doesn't simply use the time as the seed.
$ perl -M5.014 -E'say for srand, srand'
2665271449
1007037147
Your goal seems to be how to generate random numbers rather than how to generate seeds. In most cases, just use a cryptographic RNG (such as Crypt::URandom in Perl) to generate the random numbers you want, rather than generate seeds for another RNG. (In general, cryptographic RNGs take care of seeding and other issues for you.) You should not use a weaker RNG unless—
the random values you generate aren't involved in information security (e.g., the random values are neither passwords nor nonces nor encryption keys), and
either—
you care about repeatable "randomness" (which is not the case here), or
you have measured the performance of your application and find random number generation to be a performance bottleneck.
Since you will generate random names for the purpose of querying a database, which may be in a remote location, it will be highly unlikely that the random number generation itself will be the performance bottleneck.
I really need your help to understand what the dl_type=0x0800 and the nw_proto=6 mean in this command of flowvisor:
$ fvctl -f /dev/null add-flowspace dpid1-port4-video-src 1 100 in_port=4,dl_type=0x0800,nw_proto=6,tp_src=9999 video=7
Thank you!
The conventions are the same as for the Open vSwitch ovs-ofctl tool, the manpage has all the information you are looking for.
The plaintext version of the manpage can be found here.
It mentions:
The following shorthand notations are also available:
(...)
tcp Same as dl_type=0x0800,nw_proto=6.
(...)
The full descriptions have more information:
dl_type=ethertype
Matches Ethernet protocol type ethertype, which is specified as
an integer between 0 and 65535, inclusive, either in decimal or
as a hexadecimal number prefixed by 0x (e.g. 0x0806 to match ARP
packets).
nw_proto=proto
ip_proto=proto
When ip or dl_type=0x0800 is specified, matches IP protocol type
proto, which is specified as a decimal number between 0 and 255,
inclusive (e.g. 1 to match ICMP packets or 6 to match TCP pack‐
ets).
When ipv6 or dl_type=0x86dd is specified, matches IPv6 header
type proto, which is specified as a decimal number between 0 and
255, inclusive (e.g. 58 to match ICMPv6 packets or 6 to match
TCP). The header type is the terminal header as described in
the DESIGN document.
When arp or dl_type=0x0806 is specified, matches the lower 8
bits of the ARP opcode. ARP opcodes greater than 255 are
treated as 0.
When rarp or dl_type=0x8035 is specified, matches the lower 8
bits of the ARP opcode. ARP opcodes greater than 255 are
treated as 0.
When dl_type is wildcarded or set to a value other than 0x0800,
0x0806, 0x8035 or 0x86dd, the value of nw_proto is ignored (see
Flow Syntax above).
My source file has multiple serial interfaces. I want to simply output each serial line "Serial0/2/0:0" and then the following drops, aborts, etc. on the next lines in the output file under each Serial interface. So far I have this:
get-childitem show-int.log | select-string -pattern drops | foreach {$_.line}
And simply run it with > todays-date. I am a network engineer so forgive how bad I am at ps. I've tried google and putting the many items in quotes but nothing works to my satisfaction.
Serial0/2/0:0 is up, line protocol is up
Hardware is DSX1
MTU 1500 bytes, BW 1536 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 33/255, rxload 133/255
Encapsulation PPP, LCP Open, multilink Open
Link is a member of Multilink bundle Multilink1, loopback not set
Keepalive set (10 sec)
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 1d18h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops:
381
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 805000 bits/sec, 188 packets/sec
5 minute output rate 200000 bits/sec, 153 packets/sec
8320454 packets input, 2999426407 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
22 runts, 0 giants, 0 throttles
30 input errors, 29 CRC, 0 frame, 1 overrun, 0 ignored, 0 abort
7629921 packets output, 1268811436 bytes, 0 underruns
0 output errors, 0 collisions, 4294967295 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
7 carrier transitions
Not precise, but easy:
Get-Content show-int.log | select-string 'Serial0/2/0:0' -Context 0,10
I have a quick question. Its most likely user error so I apologize before I begin.
I’m trying to setup threshold for a device so that it will alert us when one of our printers is in a certain state. (Jammed, out of toner, no paper etc) I’ve found the specific oid that handles this. (1.3.6.1.2.1.25.3.5.1.2.1) The specific oid is called hrPrinterDetectedErrorState under the HOST-RESOURCE-MIB. I’ve verified that I can see the oid via SNMPWALK. My problem is interpreting the data its spitting out. What i'm reading in the MIB and what i'm seeing via SNMPWALK are different.
Here is the description of oid from the MIB:
"This object represents any error conditions detected
by the printer. The error conditions are encoded as
bits in an octet string, with the following
definitions:
Condition Bit #
lowPaper 0
noPaper 1
lowToner 2
noToner 3
doorOpen 4
jammed 5
offline 6
serviceRequested 7
inputTrayMissing 8
outputTrayMissing 9
markerSupplyMissing 10
outputNearFull 11
outputFull 12
inputTrayEmpty 13
overduePreventMaint 14
Bits are numbered starting with the most significant
bit of the first byte being bit 0, the least
significant bit of the first byte being bit 7, the
most significant bit of the second byte being bit 8,
and so on. A one bit encodes that the condition was
detected, while a zero bit encodes that the condition
was not detected.
This object is useful for alerting an operator to
specific warning or error conditions that may occur,
especially those requiring human intervention."
The odd part is that SNMPWALK says the oid is a Hex-String while the MIB specifies that it should be a Octet-String. Are the two different? Do I need to convert the data that is output by SNMPWALK somehow to get it to match up with what the MIB is saying?
To test everything, I put the printer into several different “States.” I then ran an SNMPWALK on the device to see what the oid output. Here are the results. As you will see, these results don’t match up to what the MIB specifies.
Case 1: Opened the toner door
Expected Output based on MIB: 4
SNMP Output: 08
Case 2: Removed Toner & Closed the door
Expected Output based on MIB: 1
SNMP Output: 10
Case 3: Placed 1 sheet of paper and printed a 2 page document. The printer ran out of paper.
Expected Output based on MIB: 0 or 1
SNMP Output: #
I’m confused at the output. I just need to know how to read the oid so I can setup thresholds so that when it sees, for example, a 08 it performs a certain action.
Thanks for your help!
You are reading this wrong. The data you receive back should actually be interpreted as a bit array and every bit is its own value for the specific alarm in your case
Expected Output based on MIB: 4
SNMP Output: 08
You actually get back the output:
00001000 00000000
The first byte here covers those values
lowPaper 0
noPaper 1
lowToner 2
noToner 3
doorOpen 4
jammed 5
offline 6
serviceRequested 7
So lowPaper is bit 0, noPaper is bit 1, lowToner is bit 2, etc. And doorOpen is bit 4 and as you can see that bit is set, indicating that the door is open.
EDIT:
This is very dependent on the device and implementation. To know how to parse it right involves a lot of trial and error (at least from my experience). As an example if you get back the message 9104, this could be either be
91 and 04 are separate so you first translate 91 to binary from hex and then the
same thing with 04
91: 10010001
04: 00000100
Which would mean low paper, noToner, service requested and inputTrayEmpty. This looks like the most likely way this works.
If you only get one byte back this then means you should only look for alarms in the first 8 bits. As a example of things you need to look out for: If the only alarm present is doorOpen you could be getting back only 08 but it would actually be 0008 where the first 2 hex chars are actually the second part of the alarms but aren't shown because they are none present. So in your case you actually first have to switch the bytes (if there are 4) parse the first two and the second two on their own and then you get the actual result.
As I said there is no real standard here from what i have seen and you have to just work with it until you are sure you know how the data is sent and how to parse it.
Powershell function to interpret the hrPrinterDetectedErrorState octetstring. (I feel like there's some more often used way to do this?) I've been using this module, but it doesn't even resolve hostnames to ip addresses.
The data property returned is just a string not an octetstring type. None of the printers are snmp v3.
https://www.powershellgallery.com/packages/SNMP/1.0.0.1
A single byte would have to be padded with a zero. Most of the time only one byte is sent. The bytes are in the, I think confusing, order that it's documented in. Converting two bytes to an integer results in a different order (depending on big endian or little endian order).
function snmpmessage {
param($data)
[flags()] Enum hrPrinterDetectedErrorState
{
# more common group
LowPaper = 0x0080
NoPaper = 0x0040
LowToner = 0x0020
NoToner = 0x0010
DoorOpen = 0x0008
Jammed = 0x0004
Offline = 0x0002
ServiceRequested = 0x0001
InputTrayMissing = 0x8000
OutputTrayMissing = 0x4000
MarkerSupplyMissing = 0x2000
OutputNearFull = 0x1000
OutputFull = 0x0800
InputTrayEmpty = 0x0400
OverduePreventMaint = 0x0200
}
$bytes = [byte[]][char[]]$data
if ($bytes.count -eq 1) { $bytes = $bytes[0],0 } # pad 0
$code = [bitconverter]::ToUInt16($bytes, ($startIndex=0))
[hrPrinterDetectedErrorState]$code
}
snmpmessage -join [char[]](1,4)
ServiceRequested, InputTrayEmpty
snmpmessage '#' # 0x40
NoPaper
Or:
$hrPrinterDetectedErrorState = '1.3.6.1.2.1.25.3.5.1.2.1'
$hostname = 'myprinter01'
$ip = (Resolve-DnsName $hostname).ipaddress
$result = Get-SnmpData -ip $ip -oid $hrPrinterDetectedErrorState -v v1
snmpmessage $result.data
LowToner
# ?
# $octetstring = [Lextm.SharpSnmpLib.OctetString]::new($result.data)
I am trying to import certain data into my SAS datset using this piece of code:
Data Names_And_More;
Infile 'C:\Users\Admin\Desktop\Torrent Downloads\SAS 9.1.3 Portable\Names_and_More.txt';
Input Name & $20.
Phone : $20.
Height & $10.
Mixed & $10.;
run;
The data in the file is as below:
Roger Cody (908)782-1234 5ft. 10in. 50 1/8
Thomas Jefferson (315)848-8484 6ft. 1in. 23 1/2
Marco Polo (800)123-4567 5Ft. 6in. 40
Brian Watson (518)355-1766 5ft. 10in 89 3/4
Michael DeMarco (445)232-2233 6ft. 76 1/3
I have been trying to learn SAS and while going through Ron Cody's book Learning SAS by example,I found to import the kind of data above, we can use 'the ampersand (&) informat modifier. The ampersand, like the colon,says to use the supplied informat, but the delimiter is now two or more blanks instead of just one.' (Ron's words, not mine). However, while importing this the result (dataset) is as follows:
Name Phone Height Mixed
Roger Cody (908)782- Thomas Jefferson Marco Polo
Also, for further details the SAS log is as follows:
419 Data Names_And_More;
420 Infile 'C:\Users\Admin\Desktop\Torrent Downloads\SAS 9.1.3 Portable\Names_and_More.txt';
421 Input Name & $20.
422 Phone : $20.
423 Height & $10.
424 Mixed & $10.
425 ;run;
NOTE:
The infile 'C:\Users\Admin\Desktop\Torrent Downloads\SAS 9.1.3 Portable\Names_and_More.txt' is:
File Name=C:\Users\Admin\Desktop\Torrent Downloads\SAS 9.1.3 Portable\Names_and_More.txt,
RECFM=V,LRECL=256
NOTE:
LOST CARD.
Name=Brian Watson (518)35 Phone=Michael Height=DeMarco (4 Mixed= ERROR=1 N=2
NOTE: 5 records were read from the infile 'C:\Users\Admin\Desktop\Torrent Downloads\SAS 9.1.3
Portable\Names_and_More.txt'.
The minimum record length was 37.
The maximum record length was 47.
NOTE: SAS went to a new line when INPUT statement reached past the end of a line.
NOTE: The data set WORK.NAMES_AND_MORE has 1 observations and 4 variables.
NOTE: DATA statement used (Total process time):
real time 0.17 seconds
cpu time 0.14 seconds
I am looking for some help with this one. It'd be great if someone can explain what exactly is happening, what am I doing wrong and how to correct this error.
Thanks
The answer is in the explanation in Ron Cody's book. & means you need two spaces to separate varaibles; so you need a second space after the name (and other fields with &).
Wrong:
Roger Cody (908)782-1234 5ft. 10in. 50 1/8
Right:
Roger Cody (908)782-1234 5ft. 10in. 50 1/8