Productivity3000: How do I reset multiple C bits at once?

Skip the quick fixes that burn the shift

The goal is to clear a block of internal Boolean tags such as C-000001 through on a Productivity3000 (P3000) controller without writing one reset coil per bit. Three quick fixes come up first, and each one costs time.

• Sixteen RST coils in a column. It works, but every added bit means another edit, and it is easy to miss one. It also does not scale past a screen or two.
• Hunting for a range RST. DirectSOFT5 on the older DirectLOGIC CPUs accepts a start and end address on one coil (C1 to C16 with RST). Do not spend time looking for that form in the P3000 software. The P3000 approach is a data-move instruction that writes a list of Boolean tags in one pass.
• Converting everything to an array for 16 bits. A 1-D Boolean array with Fill Array works, but it means re-tagging existing logic. It is only worth doing for large blocks, which Check 4 covers.

What restores production fastest is UnpackBits (UPKB) with a constant source of 0. CopyData (CPD) with one source and a list of destinations is the second choice. Get it running with one of these, then clean it up properly.

Check 1: Count the bits and read the tag names

Before you pick an instruction, open the Tag Database and write down two things.

1. How many bits need to change. UPKB handles up to 32 Boolean destinations per instruction.
2. Whether the tag names are sequential. For example, check whether they run C-000001, , and so on, with no gaps.

UPKB and CPD write only the tags you list. That lets you skip bits, for example resetting every other one, without extra instructions. A DS5-style range reset clears the whole block, so skipping bits there needs several coils.

Check 2: Decide whether every bit goes to the same state

Look at what the logic needs after the reset event.

• All bits OFF: use a source constant of 0 on UPKB. Every listed bit goes to 0. Go to the Procedure.
• Some ON, some OFF: you need a pattern word. Go to Check 3.
• All ON: use a source with every relevant bit set, for example 65535 for 16 destinations. Go to the Procedure.

Mechanism you need here: UPKB takes an integer source and copies bit 0 to the first tag in the list, bit 1 to the second, and so on. It writes every listed destination every scan the rung is true. It is not a reset-only instruction. A bit whose source position is 1 gets turned ON.

If other logic SETs any of these C bits, an UPKB on an always-true rung will overwrite them every scan. Drive the rung from a one-shot or an edge contact on the reset condition, not a maintained contact.

Check 3: Build the pattern word for a mixed ON/OFF result

Each position in the UPKB destination list has a binary weight. Position n (counting from 1) has weight 2^(n-1). Add up the weights of the positions you want ON. That sum is your source value.

Worked examples, with C-000001 as position 1:

• First three bits ON, the rest OFF: 1 + 2 + 4 = 7.
• Bits 7, 8, and 9 ON: 64 + 128 + 256 = 448.

Pitfall: writing the pattern as a binary number. Suppose you want "first three ON, last six OFF" and write it as 111000000. Read as binary, that is 448, which turns ON positions 7, 8, and 9. That is the opposite end of the list.

Binary notation puts the least significant bit on the right. UPKB puts the least significant bit in the first list position. For the first three ON, the binary form is 000000111, which is 7.

For a fixed pattern, use a constant source. For a pattern operators or recipes change at runtime, use a 16-bit or 32-bit integer tag as the source. Make that tag retentive if the pattern must survive a power cycle.

Check 4: Pick the instruction for large, scattered, or mixed-type writes

A practical CPD use is a single fault-latch reset. One instruction clears a group of alarm bits, writes a new error code to an integer tag, and loads a string into a message-board tag.

Use one source for many destinations. You do not need a separate source entry per destination. If a list mixes types, keep the Booleans at the top so the conversion from the source value is predictable.

Once the count passes 32, stop stacking UPKB instructions. Define the bits as a 1-D Boolean array and clear the whole array with Fill Array and a value of 0. Only take this route if you can re-tag the existing references during a planned change, not at 3 a.m. with the line down.

Build the UnpackBits reset rung

1. Open the task that owns the reset logic and add a rung with your reset condition, for example a reset pushbutton or an HMI reset bit.
2. Put a one-shot or edge contact on the condition so the instruction fires once per reset request. It must not rewrite the bits every scan.
3. Insert UnpackBits (UPKB) as the output.
4. Set the source to constant 0 for a full reset. For a pattern, use the value from Check 3 or an integer tag.
5. Click the first destination field and enter C-000001.
6. Press Ctrl-Enter to auto-fill the next sequential tag names down to . The maximum is 32 destinations per instruction.
7. Delete any positions you want to leave untouched, or re-point them to other tags. The list does not have to be contiguous.
8. Accept the instruction, run a project check, and transfer to the CPU using your site's download procedure.
9. Delete the old stack of individual RST coils only after verification passes.

The CPD version follows the same steps. Enter one source (0) and list the C bits as destinations. Add integer or string destinations after the Booleans if the reset should also clear a fault code or message.

Verify the fix before you leave the machine

1. Open a Data View with every destination tag and the source tag, if you used one.
2. Force or set several of the C bits ON manually.
3. Trigger the reset condition once.
4. Confirm every listed bit reads 0, or matches your pattern, and that unlisted bits did not change.
5. For a pattern word, compare each destination against the weight table. Position 1 must follow the least significant bit.
6. Let the machine run a full cycle. Confirm that bits set by process logic after the reset stay set. If they drop back to 0 immediately, the UPKB rung is not one-shot.

FAQ