Derived tag, multiple bit to modbus tag

Ignition
1

Hi all,

Need some advice on how to solve this. We use derived tags to set and reset bits in a modbus int, command word. This works as long as we do bit by bit. But… I got some buttons that is intended to alter 3 bits at once. It seems that we run into some timing issues, as only the last instruction is done.

I have tried both system.tag.write and system.tag.writeAll on my 3 derived tags.

Button 1
Set bit 10
Res bit 11
Res bit 12

Button 2
Res bit 10
Set bit 11
Res bit 12

Button 3
Res bit 10
Res bit 11
Set bit 12

Example derived tag:

Read expression:
getBit(toInt({source}),12)

Write expression:
if({value},
toInt({source}) | (1 << 12),
toInt({source}) & ~(1 << 12))

IGN 8.0.9

Thanks in advance.

2

Enable the “Optimistic Writes” option for the tag group these tags belong to.

3

Hi Kevin,

We tried this with no luck.

4

Hi Kevin,

Restored the gateway on our test server and connected to a PLC on my desk.

Enabling optimistic write does nothing, first when we change optimistic write timeout from 0 to 3000 we see a difference. It works better, meaning two or more bit is not high at the same time - but the first press will most times only disable bits. It will require a second or more click to enable the bit we would like to set.

3 buttons, 3 bits that needs to be altered. All of them belong in a UDT. Tried to add derived tags without a UDT but still the same.

Script, event:

system.tag.write("[TKV_TagProvider]D52_HFS_Kjoling/HFS/OBJ/Kommando/Pri P2",False)
system.tag.write("[TKV_TagProvider]D52_HFS_Kjoling/HFS/OBJ/Kommando/Pri Alt",False)
system.tag.write("[TKV_TagProvider]D52_HFS_Kjoling/HFS/OBJ/Kommando/Pri P1",True)

5

Also tried writeAll, still the same.

6

It works for me when using writeBlocking:

tags = [
"[default]IntBits_Instance/Bit0",
"[default]IntBits_Instance/Bit1",
"[default]IntBits_Instance/Bit2",
"[default]IntBits_Instance/Bit3"
]

values = [1,1,1,1]

system.tag.writeBlocking(tags, values)

or

system.tag.writeBlocking(["[default]IntBits_Instance/Bit0"], [1])
system.tag.writeBlocking(["[default]IntBits_Instance/Bit1"], [1])
system.tag.writeBlocking(["[default]IntBits_Instance/Bit2"], [1])
system.tag.writeBlocking(["[default]IntBits_Instance/Bit3"], [1])

It didn’t work with individual async writes, though, and I’m not sure if that’s correct behavior or not. I’ll have to open a ticket and get someone to look into it this week.

7

Hi Kevin, thanks for writing back.

I tried using writeBlocking now. Its maybe a bit improved. I had to swap about 8-9 times before it failed again. My command word is set to zero.

Looking forward to what the ticket brings. Have a nice day.

8

Hi Kevin,

Do you have any news for us? :slightly_smiling_face:

9

Sorry, this fell off my radar. I just wrote up a ticket so it won’t get forgotten.

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