Project: pump station with sequence

This week gave you all the building blocks for a step sequence: the state in a register, the jump table with a catch, the time per state and a fault that has to be acknowledged. The project puts them together into a plant that stands in many bases: a basin that is filled at the push of a button, held for a while and drained again – for example a buffer tank in which hot gas is meant to cool down before it moves on.

The plant#

The step sequence#

If the analyzer is missing, the plant goes from every state into the fault state with cause 3, all pumps off. An unknown state leads to cause 4. The display “Ursache” shows the first cause until it is acknowledged.

Setting the cause in the state block#

The only new thing is that a transition into the fault state brings its reason along. For that the block sets a second register reason, which starts at 0 every tick:

s_filling:
sgt tmp ticks MAXFILL
select next tmp FAULT next
select reason tmp C_FILL reason
sge tmp pressure FULL
select next tmp HOLDING next
j output

In the output you only take over reason if the plant really goes into the fault state. If the basin does fill up in the last allowed tick, success wins and the cause stays empty. After that you latch as on day 137: select cause cause cause reason.

Milestones#

1. Start fills the basin, a full basin moves on to Holding
2. Holding lasts 10 s, then the basin is drained, and empty means Ready again
3. Filling takes too long: fault with cause 1, pumps off, flashing light on, Start has no effect
4. Draining takes too long: fault with cause 2
5. Unknown state: fault with cause 4, acknowledging leads back to Ready
6. Analyzer gone: fault with cause 3, all pumps off, acknowledging has no effect