Issue
What does Read & Print do and how is it set?
Description
In a normal production, products are personalized in the sequence given by the address file.
In Read & Print or Random Production, a key has to be read before one can even start to print. Reading is done by means of a Camera, OCR reader, barcode reader, magnetic reader, or any other reader.
To produce in a random mode, the address file must be first indexed with the key expected from the reader. Of course, this key or code must be in the address file supplied and must be unique.
In this production mode, you can actually pass the same product many times through the production line, it will be printed again and again with the same record.
Thus, always remember that this mode is only as good as the key delivered by the reader. That is, if your reader sends 09876, the record 09876 is going to be printed. If you setup the reader, for example a camera, that sometimes the “6” is taken for “8”, the controller will not print 09876 but 09878. DO NOT BLAME THE CONTROLLER FOR FALSE READER RESULTS! Remember you can use check digits, explained below.
If you know the sequence the cards should come, run Matching production mode.
If you don’t know the sequence the cards should come, run Random production mode.
The proprietary GT algorithm allows minimal time searching for the record associated with the key is below 50 microseconds. 180’000 p/h solid has been tested in the field with a fast inkjet.
Timing
Please check for bottlenecks using below points.
1) Time between trigger and result from reader.
If the reader is too slow to take the image, process it, and send the result, the whole speed is in jeopardy. Good barcode readers and cameras take around 20 milliseconds for this.
2) Time from getting the result to finding the data,
The search takes 50 microseconds, the complete handling 10 mS.
3) Sending the data to the inkjet or magnetic encoder
If the inkjet has a serial connection of say 19’200 baud, that is around 1’000 bytes/s with handshaking or 1 byte per mS. So, if the message is 200 bytes, it takes 200 mS to send the complete message.
4) Inkjet or magnetic encoder to process message.
This depends on the manufacturer. It is important that the receiving device (inkjet or magnetic encoder) buffers what the controllers sends. Handshaking nowadays is a waste of time, all electronics have plenty of buffers because it costs nothing.
New electronic begins to make the image as it receives the message. Very little time.
However, old electronic uses to handshake for lack of memory or creativity. A maximum product rate of 10’000 p/h can be attained.
Important note: if printing from any photocell other than Product Detect 1, you have to reference the inkjet to a photocell that is placed after the reader.
Setup
First the random production mode has to be selected. That tells the controller you want to produce depending on a random number sent by a reader and not like usually sequentially from an address file:
Second, you have to define the key in the address file. Obviously, it represents the same number that the reader is going to read and send to the controller. Usually a customer number, credit card number, etc.
Since the address file will be sorted or indexed with this number, it is called the Sort Key. After saving the definition, press [D] to make database. Select address file.
The EditorGT will index the database and show you the result.
Warning: please check that double is equal 0. If not, equal keys appear more than once per record. A sign that the address file or key is wrong !
Select database file if you want to check the database produced, enter a key.
Above, you see a typical configuration for read & print. First the reader and later the inkjet.
You see also a gate. Remember that a reader is not always successful reading. The EditorGT allows you to define a gate for products that could not be read and consequently could not be printed on. Every Read & Print application should have a divert gate !
Reader
The reader mode has to be set to Read and print. Trigger position and length depend on the position of the camera in reference to Product detect 1 in this case.
If you want to stop the machine after a number of errors in sequence, enter a number. If a reader does not read 3 times in a row, it is because there is a jam, the illumination is wrong, and many more reasons.
Since a reader can send a result that is longer than the key itself, the EditorGT allows you to extract from the result from a position in the string and a certain length. Match it allows you to take the “As is”, take “Just numbers” filter everything else out, “cut spaces” filter spaces out, Modulo10 digit ( camera send “56353271”, 5+6+3+5+3+2+7=31 mod 10 is 1 is OK, if the 6 was mistaken for an 8 by the camera, “58353271”, 5+8+3+5+3+2+7=33 mod 10 is 3 but 1 is NOK). With modulo, you can notice false readings !
Example:
If the product reads “52437”, the camera usually sends “52437” to the controller but it can mistake a 3 for an 8 and send “52487”.
Now, the controller does not know that a 3 was replaced with an 8 and just searches for “52487” instead of “52437”.
Two things can happen:
1) There is a record “52487” in the database and it will be printed once. Later, when the real record “52487” comes, it is printed another time, duplicate !!!
2) There is no record “52487” in the database, thus nothing will be printed and you’ll see in the log file a message: key “52487” not found.
Thus, if you’re not sure the reader reads always 100% accurate; you better add a check digit. By the way, that is what most barcodes have, a check digit to avoid this problem.
Time Trigger-result will tell the controller to expect a result from the camera in a certain time frame. Some readers do not send anything if they cannot read.
Other tips
You can setup the reader, by calling the test menu on the right side of the application.
Set a product below the reader and press the trigger.
You will see the result and the time it took the reader to read and transmit the result. This time tells you how fast the reader can read, ultimately how fast you can produce with this reader.
When you start production, you will see now that you can enter a key (here 0999) and search for the record in no time.
Good Read & Print !