Mixing
Convert Bits to Bytes in Node-Red
I'm new to JavaScript and I use Node-Red to read an write from a Database.
I receive from the database an object that contains the status of 8 digital inputs.
Each inputs is represented as a bit.
I'm looking for a method to combine each bits into a byte.
This is the object that I receive from the database:
array[1]
0: object
idx: 10
ts: "2018-11-21T06:12:45.000Z"
in_0: 1
in_1: 1
in_2: 1
in_3: 1
in_4: 1
in_5: 1
in_6: 1
in_7: 1
in_x represent the input position.
As out I would like to receive a byte that represent the combination of each single byte.
For example:
in0: 0,
in1: 1,
in2: 0,
in3: 0,
in4: 0,
in5: 1,
in6: 0,
in7: 0,
The output byte will be: 00100001 in binary that converted to byte is 33
Any suggestions?
Thanks in advance.
javascript bit-manipulation node-red
asked Nov 21 '18 at 8:52
FedericoFederico
3141519
add a comment |
I'm new to JavaScript and I use Node-Red to read an write from a Database.
I receive from the database an object that contains the status of 8 digital inputs.
Each inputs is represented as a bit.
I'm looking for a method to combine each bits into a byte.
This is the object that I receive from the database:
array[1]
0: object
idx: 10
ts: "2018-11-21T06:12:45.000Z"
in_0: 1
in_1: 1
in_2: 1
in_3: 1
in_4: 1
in_5: 1
in_6: 1
in_7: 1
in_x represent the input position.
As out I would like to receive a byte that represent the combination of each single byte.
For example:
in0: 0,
in1: 1,
in2: 0,
in3: 0,
in4: 0,
in5: 1,
in6: 0,
in7: 0,
The output byte will be: 00100001 in binary that converted to byte is 33
Any suggestions?
Thanks in advance.
javascript bit-manipulation node-red
asked Nov 21 '18 at 8:52
FedericoFederico
3141519
Will you please explain a bit, what exactly you are expecting in output.
– Anki
Nov 21 '18 at 8:55
What have you already tried? Also what representation is the data in LSB, MSB, 2's complement binary?
– hardillb
Nov 21 '18 at 8:57
add a comment |
I'm new to JavaScript and I use Node-Red to read an write from a Database.
I receive from the database an object that contains the status of 8 digital inputs.
Each inputs is represented as a bit.
I'm looking for a method to combine each bits into a byte.
This is the object that I receive from the database:
array[1]
0: object
idx: 10
ts: "2018-11-21T06:12:45.000Z"
in_0: 1
in_1: 1
in_2: 1
in_3: 1
in_4: 1
in_5: 1
in_6: 1
in_7: 1
in_x represent the input position.
As out I would like to receive a byte that represent the combination of each single byte.
For example:
in0: 0,
in1: 1,
in2: 0,
in3: 0,
in4: 0,
in5: 1,
in6: 0,
in7: 0,
The output byte will be: 00100001 in binary that converted to byte is 33
Any suggestions?
Thanks in advance.
javascript bit-manipulation node-red
asked Nov 21 '18 at 8:52
FedericoFederico
3141519
I'm new to JavaScript and I use Node-Red to read an write from a Database.
I receive from the database an object that contains the status of 8 digital inputs.
Each inputs is represented as a bit.
I'm looking for a method to combine each bits into a byte.
This is the object that I receive from the database:
array[1]
0: object
idx: 10
ts: "2018-11-21T06:12:45.000Z"
in_0: 1
in_1: 1
in_2: 1
in_3: 1
in_4: 1
in_5: 1
in_6: 1
in_7: 1
in_x represent the input position.
As out I would like to receive a byte that represent the combination of each single byte.
For example:
in0: 0,
in1: 1,
in2: 0,
in3: 0,
in4: 0,
in5: 1,
in6: 0,
in7: 0,
The output byte will be: 00100001 in binary that converted to byte is 33
Any suggestions?
Thanks in advance.
javascript bit-manipulation node-red
javascript bit-manipulation node-red
asked Nov 21 '18 at 8:52
FedericoFederico
3141519
asked Nov 21 '18 at 8:52
FedericoFederico
3141519
edited Nov 21 '18 at 11:05
Federico
asked Nov 21 '18 at 8:52
FedericoFederico
3141519
asked Nov 21 '18 at 8:52
FedericoFederico
3141519
asked Nov 21 '18 at 8:52
FedericoFederico
3141519
3141519
Will you please explain a bit, what exactly you are expecting in output.
– Anki
Nov 21 '18 at 8:55
What have you already tried? Also what representation is the data in LSB, MSB, 2's complement binary?
– hardillb
Nov 21 '18 at 8:57
add a comment |
Will you please explain a bit, what exactly you are expecting in output.
– Anki
Nov 21 '18 at 8:55
What have you already tried? Also what representation is the data in LSB, MSB, 2's complement binary?
– hardillb
Nov 21 '18 at 8:57
Will you please explain a bit, what exactly you are expecting in output.
– Anki
Nov 21 '18 at 8:55
Will you please explain a bit, what exactly you are expecting in output.
– Anki
Nov 21 '18 at 8:55
What have you already tried? Also what representation is the data in LSB, MSB, 2's complement binary?
– hardillb
Nov 21 '18 at 8:57
What have you already tried? Also what representation is the data in LSB, MSB, 2's complement binary?
– hardillb
Nov 21 '18 at 8:57
add a comment |
1 Answer
1
active
oldest
votes
The following code works as you requested*:
var output =
arr[0].in_0 +
(arr[0].in_1 << 1) +
(arr[0].in_2 << 2) +
(arr[0].in_3 << 3) +
(arr[0].in_4 << 4) +
(arr[0].in_5 << 5) +
(arr[0].in_6 << 6) +
(arr[0].in_7 << 7);
This code assumes that each variable can only be a 1 or a 0. Anything else will result in nonsense.
I have used the Left Bit Shift operator (<<) to obtain the power of two for each on bit.
You have specified that in_7 is the Most Significant Bit. If it is actually the Least Significant Bit, reverse the order of the in_x variables.
*The result is not a byte, but it does contain the number that I think you're expecting.
answered Nov 21 '18 at 9:34
Gary OttGary Ott
20128
Thanks for the reply but as output I need a byte obtained with Bit Shift. This because the byte will be sent to a Shift Register in order to enable relays.
– Federico
Nov 21 '18 at 10:46
Can you provide any more details on the requirements of whatever system you're trying to enter the data into? Perhaps it expects input in a Uint8 Array?
– Gary Ott
Nov 21 '18 at 11:16
See developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Gary Ott
Nov 21 '18 at 11:16
The byte obtained will be sent to a PLC via node-red. So I need an integer.
– Federico
Nov 21 '18 at 12:06
1
I'm sorry I misinterpreted the answer. It's works! Thank you very much
– Federico
Nov 21 '18 at 13:59
|
show 2 more comments
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
The following code works as you requested*:
var output =
arr[0].in_0 +
(arr[0].in_1 << 1) +
(arr[0].in_2 << 2) +
(arr[0].in_3 << 3) +
(arr[0].in_4 << 4) +
(arr[0].in_5 << 5) +
(arr[0].in_6 << 6) +
(arr[0].in_7 << 7);
This code assumes that each variable can only be a 1 or a 0. Anything else will result in nonsense.
I have used the Left Bit Shift operator (<<) to obtain the power of two for each on bit.
You have specified that in_7 is the Most Significant Bit. If it is actually the Least Significant Bit, reverse the order of the in_x variables.
*The result is not a byte, but it does contain the number that I think you're expecting.
answered Nov 21 '18 at 9:34
Gary OttGary Ott
20128
Thanks for the reply but as output I need a byte obtained with Bit Shift. This because the byte will be sent to a Shift Register in order to enable relays.
– Federico
Nov 21 '18 at 10:46
Can you provide any more details on the requirements of whatever system you're trying to enter the data into? Perhaps it expects input in a Uint8 Array?
– Gary Ott
Nov 21 '18 at 11:16
See developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Gary Ott
Nov 21 '18 at 11:16
The byte obtained will be sent to a PLC via node-red. So I need an integer.
– Federico
Nov 21 '18 at 12:06
1
I'm sorry I misinterpreted the answer. It's works! Thank you very much
– Federico
Nov 21 '18 at 13:59
|
show 2 more comments
The following code works as you requested*:
var output =
arr[0].in_0 +
(arr[0].in_1 << 1) +
(arr[0].in_2 << 2) +
(arr[0].in_3 << 3) +
(arr[0].in_4 << 4) +
(arr[0].in_5 << 5) +
(arr[0].in_6 << 6) +
(arr[0].in_7 << 7);
This code assumes that each variable can only be a 1 or a 0. Anything else will result in nonsense.
I have used the Left Bit Shift operator (<<) to obtain the power of two for each on bit.
You have specified that in_7 is the Most Significant Bit. If it is actually the Least Significant Bit, reverse the order of the in_x variables.
*The result is not a byte, but it does contain the number that I think you're expecting.
answered Nov 21 '18 at 9:34
Gary OttGary Ott
20128
Thanks for the reply but as output I need a byte obtained with Bit Shift. This because the byte will be sent to a Shift Register in order to enable relays.
– Federico
Nov 21 '18 at 10:46
Can you provide any more details on the requirements of whatever system you're trying to enter the data into? Perhaps it expects input in a Uint8 Array?
– Gary Ott
Nov 21 '18 at 11:16
See developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Gary Ott
Nov 21 '18 at 11:16
The byte obtained will be sent to a PLC via node-red. So I need an integer.
– Federico
Nov 21 '18 at 12:06
1
I'm sorry I misinterpreted the answer. It's works! Thank you very much
– Federico
Nov 21 '18 at 13:59
|
show 2 more comments
The following code works as you requested*:
var output =
arr[0].in_0 +
(arr[0].in_1 << 1) +
(arr[0].in_2 << 2) +
(arr[0].in_3 << 3) +
(arr[0].in_4 << 4) +
(arr[0].in_5 << 5) +
(arr[0].in_6 << 6) +
(arr[0].in_7 << 7);
This code assumes that each variable can only be a 1 or a 0. Anything else will result in nonsense.
I have used the Left Bit Shift operator (<<) to obtain the power of two for each on bit.
You have specified that in_7 is the Most Significant Bit. If it is actually the Least Significant Bit, reverse the order of the in_x variables.
*The result is not a byte, but it does contain the number that I think you're expecting.
answered Nov 21 '18 at 9:34
Gary OttGary Ott
20128
The following code works as you requested*:
var output =
arr[0].in_0 +
(arr[0].in_1 << 1) +
(arr[0].in_2 << 2) +
(arr[0].in_3 << 3) +
(arr[0].in_4 << 4) +
(arr[0].in_5 << 5) +
(arr[0].in_6 << 6) +
(arr[0].in_7 << 7);
This code assumes that each variable can only be a 1 or a 0. Anything else will result in nonsense.
I have used the Left Bit Shift operator (<<) to obtain the power of two for each on bit.
You have specified that in_7 is the Most Significant Bit. If it is actually the Least Significant Bit, reverse the order of the in_x variables.
*The result is not a byte, but it does contain the number that I think you're expecting.
answered Nov 21 '18 at 9:34
Gary OttGary Ott
20128
edited Nov 21 '18 at 9:41
answered Nov 21 '18 at 9:34
Gary OttGary Ott
20128
answered Nov 21 '18 at 9:34
Gary OttGary Ott
20128
answered Nov 21 '18 at 9:34
Gary OttGary Ott
20128
20128
Thanks for the reply but as output I need a byte obtained with Bit Shift. This because the byte will be sent to a Shift Register in order to enable relays.
– Federico
Nov 21 '18 at 10:46
Can you provide any more details on the requirements of whatever system you're trying to enter the data into? Perhaps it expects input in a Uint8 Array?
– Gary Ott
Nov 21 '18 at 11:16
See developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Gary Ott
Nov 21 '18 at 11:16
The byte obtained will be sent to a PLC via node-red. So I need an integer.
– Federico
Nov 21 '18 at 12:06
1
I'm sorry I misinterpreted the answer. It's works! Thank you very much
– Federico
Nov 21 '18 at 13:59
|
show 2 more comments
Thanks for the reply but as output I need a byte obtained with Bit Shift. This because the byte will be sent to a Shift Register in order to enable relays.
– Federico
Nov 21 '18 at 10:46
Can you provide any more details on the requirements of whatever system you're trying to enter the data into? Perhaps it expects input in a Uint8 Array?
– Gary Ott
Nov 21 '18 at 11:16
See developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Gary Ott
Nov 21 '18 at 11:16
The byte obtained will be sent to a PLC via node-red. So I need an integer.
– Federico
Nov 21 '18 at 12:06
1
I'm sorry I misinterpreted the answer. It's works! Thank you very much
– Federico
Nov 21 '18 at 13:59
Thanks for the reply but as output I need a byte obtained with Bit Shift. This because the byte will be sent to a Shift Register in order to enable relays.
– Federico
Nov 21 '18 at 10:46
Thanks for the reply but as output I need a byte obtained with Bit Shift. This because the byte will be sent to a Shift Register in order to enable relays.
– Federico
Nov 21 '18 at 10:46
Can you provide any more details on the requirements of whatever system you're trying to enter the data into? Perhaps it expects input in a Uint8 Array?
– Gary Ott
Nov 21 '18 at 11:16
Can you provide any more details on the requirements of whatever system you're trying to enter the data into? Perhaps it expects input in a Uint8 Array?
– Gary Ott
Nov 21 '18 at 11:16
See developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Gary Ott
Nov 21 '18 at 11:16
See developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Gary Ott
Nov 21 '18 at 11:16
The byte obtained will be sent to a PLC via node-red. So I need an integer.
– Federico
Nov 21 '18 at 12:06
The byte obtained will be sent to a PLC via node-red. So I need an integer.
– Federico
Nov 21 '18 at 12:06
1
1
I'm sorry I misinterpreted the answer. It's works! Thank you very much
– Federico
Nov 21 '18 at 13:59
I'm sorry I misinterpreted the answer. It's works! Thank you very much
– Federico
Nov 21 '18 at 13:59
|
show 2 more comments
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Will you please explain a bit, what exactly you are expecting in output.
– Anki
Nov 21 '18 at 8:55
What have you already tried? Also what representation is the data in LSB, MSB, 2's complement binary?
– hardillb
Nov 21 '18 at 8:57