How to incorporate quality into a dp function

Discussion about recent product features & solutions!
Search

Post Reply
3 posts • Page 1 of 1
User avatar
fmulder
Posts: 306
Joined: Wed Feb 03, 2010 8:46 am

How to incorporate quality into a dp function

Post by fmulder » Thu Aug 08, 2019 10:04 am

We are considering to read N variables from a PLC. The update rate will be a challenge and we're therefor considering to pack the bits into DWORDS and then use dp functions to extract the bits from the words
(Our license will be 'unlimited' so there can not be any commercial issues)

Example:
We transfer a word 'ReadWord' containing bits for 'ModeAuto' and an alarm called 'PumpFailure'. This means that the dp element 'ModeAuto' will have a dp function connected to 'ReadWord'. 'PumpFailure' will have a dp function connected to 'ReadWord'

The DP element 'ReadWord' will become invalid when we loose the connection to the PLC (This needs to be configured in the S7+ driver).

What dp function to I configure so that 'PumpFailure' becomes 'bad' then 'ReadWord' has the status bad. ( I believe that you can not choose '.._original.._bad' in the PARA )

Thanks for your answer

share the fun
Frenk Mulder

User avatar
leoknipp
Posts: 1869
Joined: Tue Aug 24, 2010 5:28 pm

Re: How to incorporate quality into a dp function

Post by leoknipp » Thu Aug 08, 2019 1:51 pm

I didn't test it but I'm pretty sure that you can connect to the statusbits in a dp function.
E.g. the following configuration should be possible:
p1 = DP1.value:_online.._value
p2 = DP1.value:_online.._userbit1
p3 = DP2.value:_online.._value
p4 = DP2.value:_online.._userbit1

You have to configure all attributes for the same element one after the other as shown in the example above.

Best Regards
Leopold Knipp
Senior Support Specialist

gschijndel
Posts: 71
Joined: Tue Jan 15, 2019 2:12 pm

Re: How to incorporate quality into a dp function

Post by gschijndel » Wed Aug 14, 2019 1:06 pm

The license should never be a reason to pack bits in dwords. Does your PLC not have enough subscriptions available to read all bits without packing them?

Transferring statusbits is only possible with statistical dp functions.

Post Reply
3 posts • Page 1 of 1