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Siemens 505 Workshop, how to change a PID loop from auto to manual?

Created by: kaisrmaulo5 at: 6/9/2020 12:47 PM (3 Replies)

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6/9/2020 12:47 PM	Rate (0)
kaisrmaulo5 Posts: 1 Rating: (0)	I am upgrading this 20 year old HMI to a factory talk version of it. It is using a CVU10000 from TI that is the interface part, and there is a very large and old siemens PLC it is talking too. On my loops overview page in the old HMI there are some loops that can be changed from auto/manual, and I am confused if when they are in [snip] manual, if the PID is still "active" per say and they are just changing the PID output to manually control the valve position. Or, if they are changing it to manual by turning the PID off and controlling the valve some other way. I have looked in the run [snip] gs and found where it goes to manual/auto, but it seems to be controlled by the PID and not the HMI. Ex. When in auto mode, if the tank is above 50% it switches to manual, releasing medium to go below 50%, then once below 50% it kick to auto mode to try and maintain that 50% level. However, in startup, they need to be able to change it to manual and manually change the valve position (to 100%) to fill the tank to 80%. In in the HMI on the loop overview there is a (manual/auto) toggle they hit. I have gone behind the scenes on a computer that has the old HMI program but have yet to find out how that is taking place and w[snip] hat tag it is writing to in the PLC. Any help is appreciated!
kaisrmaulo5 Posts: 1 Rating: (0)	Last edited by: kaisrmaulo5 at: 06/10/2020 09:13:02 Last edited by: Jen_Moderator at: 06/22/2020 07:27:35 Removed links, because it's spam.
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6/9/2020 1:12 PM	Rate (0)
SamTheEagle Bronze-Expert Joined: 2/10/2006 Last visit: 10/8/2024 Posts: 148 Rating: (12)	Dear Sir, In the title you mention that you are using 505 workshop. Please note that 505 Workshop is not a Siemens Product. If you need support on 505 Workshop please contact support@napa.fr Kind regards, Carlo

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6/9/2020 1:26 PM	Rate (1)
SamTheEagle Bronze-Expert Joined: 2/10/2006 Last visit: 10/8/2024 Posts: 148 Rating: (12)	Further to your question: the way the auto/ manual state of a PID loop is controlled in a TI555 Controller is by means of the LVF attribute of the PID loop. Please see attached extract of the manual. The Loop V-flag is a 16 bit word. it can be configured as 1 v-memory or 16 consecutive C-coils. bit 1, 2 and 3 are used to set the PID loop state. Your CVU 10 000 is certainly writing to these bits. You can only set one of the 3 bits at a time, the other ones must be zero. bit 4 and 5 are read-only and used to determine the state of the PID loop. They will reflect if the command has been taken into account. Your CVU 10 000 will certainly read bit 4 & 5 to display the state of the PID Loop. So, yes the state of the PID is controlled inside the TI555 PLC and the CVU 10 000 merely works as an interface to change the command bits. Hope this helps, Regards, Carlo Attachment LVF.pdf (1138 Downloads)

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6/20/2020 11:44 PM	Rate (0)
sneazzy95 Regular Member Joined: 11/7/2019 Last visit: 12/27/2023 Posts: 3 Rating: (0)	Thanks a lot for the explanation and all the details, it helped me so much !
	Last edited by: sneazzy95 at: 08/07/2020 20:23:06 Last edited by: sneazzy95 at: 06/21/2021 22:18:19 Last edited by: sneazzy95 at: 02/19/2022 19:43:19
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This contribution was helpful to 1 thankful Users SamTheEagle

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