Industry Automation and Control Forum
This forum is addressing industrial automation design & engineering, operations, asset performance, cyber security and digital transformation for Plants & Machines.
Link copied. Please paste this link to share this article on your social media post.
Posted: 2020-01-14 06:14 AM . Last Modified: 2020-01-14 06:20 AM
Hi everyone
I am working in a Vijeo Citect v2015 application where I have LONG and ULONG data types variables, when mapped in graphic numiric representation these variables go crazy and show high value numbers instead of small correct value, I tried alteringlongdatatype parameter to all possible values, but still cant get the right values
I can use some advice
Regards
Link copied. Please paste this link to share this article on your social media post.
Link copied. Please paste this link to share this article on your social media post.
Posted: 2020-01-14 07:54 AM
Hello Osama,
This depends on the protocol used.In case of the MODNET protocol driver the Citect Help shows:
In the MODNET protocol, LONG data types default to a simplified implementation, with a shortened range of 0 to 99,999,999 for mode 0. | 0 - implies 10,000 * low register + high register |
Mode 2 has the same range as mode 0, but with the register order swapped. | 1 - implies 65,536 * low register + high register |
Mode 1 supports the complete LONG range of -2,147,483,648 to +2,147,483,647. Mode 3 has the same range as mode 1, but with the register order swapped. | 2 - implies 10,000 * high register + low register |
When using the MODBUS protocol, Citect SCADA combines two registers to store a long data type in a PLC. The way in which it does this is defined by this parameter. | 3 - implies 65,536 * high register + low register |
Note: This parameter is not applicable if you are using the protocol variant MODNET20 or MODNET30 to communicate with a device. Under these circumstances, a value of 3 will be hardcoded for this parameter.
With this parameter, you can set different values for specific I/O devices or groups of I/O devices. See Device/group-specific parameters.
Default is 3
br
Rene
Link copied. Please paste this link to share this article on your social media post.
Link copied. Please paste this link to share this article on your social media post.
Posted: 2020-01-14 08:21 AM
Hello Rene
Yes I am implementing the basic variant MODNET, and I already tried all these parameters for longdatatype set to 0,1,2 and 3 , I can read from the device with Modscan with no problems, Citect for some reason can not display the values correctly
Link copied. Please paste this link to share this article on your social media post.
Link copied. Please paste this link to share this article on your social media post.
Posted: 2020-01-14 04:17 PM
Well.. .. if you already tried all possible LongDataType and the data is still showing up crazy.. . . i can only think of a possible address shift.. Eg... if you are polling tag address 40001, try setting that to 40000 or 40002. See what happens.
Link copied. Please paste this link to share this article on your social media post.
Link copied. Please paste this link to share this article on your social media post.
Posted: 2020-01-15 03:06 AM
Hi Kingslim
I am sure that I am reading the meant registers
, this is really confusing
thanx for response
Link copied. Please paste this link to share this article on your social media post.
Link copied. Please paste this link to share this article on your social media post.
Posted: 2020-01-16 08:20 AM
It would still be worth trying to read what you think are the 'wrong' registers.
You wouldn't be the first person to be caught out by the Modbus address shift.
Link copied. Please paste this link to share this article on your social media post.
Link copied. Please paste this link to share this article on your social media post.
Posted: 2020-01-16 07:10 PM
Some modbus devices use 1-based addressing, others use 0-based addressing. When master and slave have different address base, the "shift" occurs. The fastest way to identify this issue is indeed by trial and error, since not all manufacturer state this in the modbus device manual.
Link copied. Please paste this link to share this article on your social media post.
Create your free account or log in to subscribe to the board - and gain access to more than 10,000+ support articles along with insights from experts and peers.