File view

IO_Site_Config_Matrix.md

      
            # PLC-5000 I/O Site Configuration Matrix
          
            ## Hardware Constraints
          
            | Resource          | Max | Define         |
          
            |-------------------|-----|----------------|
          
            | Output Bits       | 8   | `N_OUTPUTS`    |
          
            | IS Input Bits     | 8   | `N_INPUTS`     |
          
            | AC Input Bits     | 8   | `N_AC_INPUTS`  |
          
            | Channels/Turbines | 4   | `N_ISM`        |
          
            | Products          | 4   | `N_PROD`       |
          
            | Piston Switches   | 4   | `N_PRES_INPUTS`|
          
            | Auth Inputs       | 4   | `N_AUTH_INPUTS` |
          
            Compile-time flags assumed (current defaults from `PLC.c`):
          
            - `MODBUS_M_ON = 1` (LDN pressure via Modbus master)
          
            - `ALARM_PER_PROD = 1` (one alarm output per product, not per channel)
          
            - `CV_ON = 1` (control valves enabled)
          
            - `RESET_ALL_INPUT = 1` (last free AC input = Reset All)
          
            - `DISABLE_INPUT = 0` (auth inputs are NOT used as disable)
          
            ---
          
            ## General Output Mapping Formula (Bits 0-7)
          
            ```
          
            Bit Range                           | Function
          
            ------------------------------------|--------------------------------------------
          
            0  to  T-1                          | Turbine Pump outputs (1 per turbine)
          
            T  to  3                            | UNUSED (gap if T < 4)
          
            4  to  4+C-1                        | Control Valve outputs (CV_OFFSET = 4)
          
            4+C  to  4+C+P-1                    | Alarm outputs (1 per product)*
          
            ```
          
            Where:
          
            - **T** = total turbines across all products (`Config.N_Turbines`)
          
            - **C** = total control valves across all products (`Config.N_CVs` = sum of all SCV+PCV+DCV)
          
            - **P** = number of products (`Config.N_Products`)
          
            ### CV Output Sub-ordering (within the CV range)
          
            For each product sequentially:
          
            1. **SCV** (Solenoid Control Valves) first
          
            2. **PCV** (Pressure Control Valves) next
          
            3. **DCV** (Demand Control Valves) last
          
            ```
          
            Product 0 SCVs → Product 0 PCVs → Product 0 DCVs → Product 1 SCVs → Product 1 PCVs → ...
          
            ```
          
            ### Alarm Output Overflow Rules
          
            | Condition                  | Behavior                                      |
          
            |----------------------------|-----------------------------------------------|
          
            | `C <= 4 - P`              | Individual alarm output per product at bit 4+C+i |
          
            | `4 - P < C < 4`           | Combined alarm for all products at bit 7      |
          
            | `C >= 4`                  | NO alarm output (all output bits consumed by CVs) |
          
            *Source: `WriteOutputs()` in `plc_outputs.lib`*
          
            ---
          
            ## General Input Mapping Formula
          
            ### IS Inputs (Intrinsically Safe - `Inputs[]` array)
          
            ```
          
            Bit Range         | Function
          
            ------------------|--------------------------------------------------
          
            0  to  PS-1       | Sump Sensor + High Pressure Switch (per piston switch)
          
            PS to  7          | UNUSED
          
            ```
          
            Where **PS** = total piston switches across all products (`Config.N_PS`).
          
            Each piston switch gets one IS input. Turbines within a product that exceed the piston switch count share the previous turbine's IS input (via `Channel[j].IOPS`).
          
            With `MODBUS_M_ON = 1`:
          
            - Primary pressure readings come from LDN sensors via Modbus, NOT from IS inputs
          
            - The IS input serves as: **Sump sensor** (if `NoSumpFlag = 0`) AND **high pressure switch confirmation**
          
            - Both use the same physical input bit (`SUMP_OFFSET = 0`)
          
            ### AC Inputs (Authorization - `AC_Inputs[]` array)
          
            ```
          
            Bit Range         | Function
          
            ------------------|--------------------------------------------------
          
            0  to  T-1        | Authorization input (1 per turbine/channel)
          
            T  to  2          | UNUSED (if T < 3)
          
            3                 | Reset All* (if T < 4)
          
            4  to  7          | UNUSED
          
            ```
          
            Where **T** = total turbines.
          
            *Reset All is only available when `Config.N_Turbines < N_AUTH_INPUTS (4)` and `RESET_ALL_INPUT = 1`. It uses `AC_Inputs[3]` (index `AUTH_OFFSET + N_AUTH_INPUTS - 1`).*
          
            **DCV Demand Note:** When a product has DCVs, the AC auth inputs for that product's turbines also serve as DCV demand signals. `ACInputs[Product[i].FirstTurbine + j]` controls `DCV[j]`. The same physical signal that authorizes a turbine also opens its corresponding DCV.
          
            ---
          
            ## Output Matrix by Site Configuration (Max 2 Products)
          
            ### Legend
          
            - **P1T1** = Product 1, Turbine 1 Pump output
          
            - **P1-SCV1** = Product 1, Solenoid Control Valve 1
          
            - **P1-ALM** = Product 1, Alarm output
          
            - **COMBINED-ALM** = Shared alarm output for all products
          
            - `—` = Unused
          
            ### 1-Product Configurations
          
            | Output Bit | 1P/1T/0CV | 1P/2T/0CV | 1P/2T/1SCV | 1P/2T/1S+1P | 1P/3T/0CV | 1P/4T/0CV | 1P/4T/1SCV | 1P/4T/2SCV | 1P/4T/3SCV |
          
            |:----------:|:---------:|:---------:|:----------:|:------------:|:---------:|:---------:|:----------:|:----------:|:----------:|
          
            | **0**      | P1T1      | P1T1      | P1T1       | P1T1         | P1T1      | P1T1      | P1T1       | P1T1       | P1T1       |
          
            | **1**      | —         | P1T2      | P1T2       | P1T2         | P1T2      | P1T2      | P1T2       | P1T2       | P1T2       |
          
            | **2**      | —         | —         | —          | —            | P1T3      | P1T3      | P1T3       | P1T3       | P1T3       |
          
            | **3**      | —         | —         | —          | —            | —         | P1T4      | P1T4       | P1T4       | P1T4       |
          
            | **4**      | P1-ALM    | P1-ALM    | P1-SCV1    | P1-SCV1      | P1-ALM    | P1-ALM    | P1-SCV1    | P1-SCV1    | P1-SCV1    |
          
            | **5**      | —         | —         | P1-ALM     | P1-PCV1      | —         | —         | P1-ALM     | P1-SCV2    | P1-SCV2    |
          
            | **6**      | —         | —         | —          | P1-ALM       | —         | —         | —          | P1-ALM     | P1-SCV3    |
          
            | **7**      | —         | —         | —          | —            | —         | —         | —          | —          | COMB-ALM   |
          
            ### 2-Product Configurations
          
            | Output Bit | 2P/1+1T/0CV | 2P/1+1T/1+1SCV | 2P/2+1T/0CV | 2P/2+2T/0CV | 2P/2+2T/1+1SCV |
          
            |:----------:|:-----------:|:---------------:|:-----------:|:-----------:|:---------------:|
          
            | **0**      | P1T1        | P1T1            | P1T1        | P1T1        | P1T1            |
          
            | **1**      | P2T1        | P2T1            | P1T2        | P1T2        | P1T2            |
          
            | **2**      | —           | —               | P2T1        | P2T1        | P2T1            |
          
            | **3**      | —           | —               | —           | P2T2        | P2T2            |
          
            | **4**      | P1-ALM      | P1-SCV1         | P1-ALM      | P1-ALM      | P1-SCV1         |
          
            | **5**      | P2-ALM      | P2-SCV1         | P2-ALM      | P2-ALM      | P2-SCV1         |
          
            | **6**      | —           | P1-ALM          | —           | —           | P1-ALM          |
          
            | **7**      | —           | P2-ALM          | —           | —           | P2-ALM          |
          
            ---
          
            ## IS Input Matrix by Site Configuration
          
            Assumes `N_PistonSwitches = N_Turbines` per product (typical).
          
            ### 1-Product Configurations
          
            | IS Input Bit | 1P/1T | 1P/2T | 1P/3T | 1P/4T |
          
            |:------------:|:-----:|:-----:|:-----:|:-----:|
          
            | **0**        | Sump/HiPres 1 | Sump/HiPres 1 | Sump/HiPres 1 | Sump/HiPres 1 |
          
            | **1**        | —     | Sump/HiPres 2 | Sump/HiPres 2 | Sump/HiPres 2 |
          
            | **2**        | —     | —     | Sump/HiPres 3 | Sump/HiPres 3 |
          
            | **3**        | —     | —     | —     | Sump/HiPres 4 |
          
            | **4-7**      | —     | —     | —     | —     |
          
            ### 2-Product Configurations
          
            | IS Input Bit | 2P/1+1T | 2P/2+1T | 2P/2+2T | 2P/1+3T | 2P/3+1T |
          
            |:------------:|:-------:|:-------:|:-------:|:-------:|:-------:|
          
            | **0**        | P1-Sump/HiPres | P1-Sump/HiPres 1 | P1-Sump/HiPres 1 | P1-Sump/HiPres | P1-Sump/HiPres 1 |
          
            | **1**        | P2-Sump/HiPres | P1-Sump/HiPres 2 | P1-Sump/HiPres 2 | P2-Sump/HiPres 1 | P1-Sump/HiPres 2 |
          
            | **2**        | —       | P2-Sump/HiPres   | P2-Sump/HiPres 1 | P2-Sump/HiPres 2 | P1-Sump/HiPres 3 |
          
            | **3**        | —       | —       | P2-Sump/HiPres 2 | P2-Sump/HiPres 3 | P2-Sump/HiPres   |
          
            | **4-7**      | —       | —       | —       | —       | —       |
          
            ---
          
            ## AC Input Matrix by Site Configuration
          
            ### 1-Product Configurations
          
            | AC Input Bit | 1P/1T | 1P/2T | 1P/3T | 1P/4T |
          
            |:------------:|:-----:|:-----:|:-----:|:-----:|
          
            | **0**        | Auth T1 | Auth T1 | Auth T1 | Auth T1 |
          
            | **1**        | —     | Auth T2 | Auth T2 | Auth T2 |
          
            | **2**        | —     | —     | Auth T3 | Auth T3 |
          
            | **3**        | **Reset All** | **Reset All** | **Reset All** | Auth T4 |
          
            | **4-7**      | —     | —     | —     | —     |
          
            ### 2-Product Configurations
          
            | AC Input Bit | 2P/1+1T | 2P/2+1T | 2P/2+2T | 2P/1+3T | 2P/3+1T |
          
            |:------------:|:-------:|:-------:|:-------:|:-------:|:-------:|
          
            | **0**        | P1-Auth T1 | P1-Auth T1 | P1-Auth T1 | P1-Auth T1 | P1-Auth T1 |
          
            | **1**        | P2-Auth T1 | P1-Auth T2 | P1-Auth T2 | P2-Auth T1 | P1-Auth T2 |
          
            | **2**        | —       | P2-Auth T1 | P2-Auth T1 | P2-Auth T2 | P1-Auth T3 |
          
            | **3**        | **Reset All** | **Reset All** | P2-Auth T2 | P2-Auth T3 | P2-Auth T1 |
          
            | **4-7**      | —       | —       | —       | —       | —       |
          
            **Key observations:**
          
            - **Reset All** is available at AC Input 3 ONLY when total turbines < 4
          
            - When total turbines = 4, ALL AC inputs are consumed by auth — no Reset All available
          
            - With `DISABLE_INPUT = 1` (not current default), the last turbine's AC input in each product becomes a disable input instead of auth
          
            ---
          
            ## How Shifting Works — Walkthrough
          
            ### Example: Adding a 2nd product to a 1-product / 2-turbine / 1-SCV site
          
            **Before (1P/2T/1SCV):**
          
            ```
          
            OUTPUTS:  [P1T1][P1T2][ — ][ — ][P1-SCV][ P1-ALM ][ — ][ — ]
          
                       Bit0  Bit1  Bit2  Bit3  Bit4     Bit5    Bit6  Bit7
          
            IS:       [Sump1][Sump2][ — ][ — ][ — ][ — ][ — ][ — ]
          
                       Bit0   Bit1   ...
          
            AC:       [Auth1][Auth2][ — ][RESET][ — ][ — ][ — ][ — ]
          
                       Bit0   Bit1  Bit2  Bit3   ...
          
            ```
          
            **After adding Product 2 (1 turbine, 1 SCV) → 2P / 2+1T / 1+1SCV:**
          
            ```
          
            OUTPUTS:  [P1T1][P1T2][P2T1][ — ][P1-SCV][P2-SCV][ P1-ALM ][ P2-ALM ]
          
                       Bit0  Bit1  Bit2  Bit3  Bit4    Bit5     Bit6      Bit7
          
            IS:       [P1-Sump1][P1-Sump2][P2-Sump1][ — ][ — ][ — ][ — ][ — ]
          
                       Bit0      Bit1      Bit2       ...
          
            AC:       [P1-Auth1][P1-Auth2][P2-Auth1][RESET][ — ][ — ][ — ][ — ]
          
                       Bit0      Bit1      Bit2      Bit3   ...
          
            ```
          
            **What shifted:**
          
            - Output Bit 2: `—` → **P2 Turbine 1 Pump**
          
            - Output Bit 5: `P1 Alarm` → **P2 SCV** (P1 Alarm pushed to Bit 6)
          
            - Output Bit 6: `—` → **P1 Alarm** (shifted right by 1 due to new CV)
          
            - Output Bit 7: `—` → **P2 Alarm** (new)
          
            - IS Input Bit 2: `—` → **P2 Sump/HiPres**
          
            - AC Input Bit 2: `—` → **P2 Auth T1**
          
            ### Example: Adding a CV to an existing product
          
            **Before (1P/2T/0CV):**
          
            ```
          
            OUTPUTS:  [P1T1][P1T2][ — ][ — ][ P1-ALM ][ — ][ — ][ — ]
          
                       Bit0  Bit1  Bit2  Bit3   Bit4    Bit5  Bit6  Bit7
          
            ```
          
            **After adding 1 SCV → 1P/2T/1SCV:**
          
            ```
          
            OUTPUTS:  [P1T1][P1T2][ — ][ — ][ P1-SCV ][ P1-ALM ][ — ][ — ]
          
                       Bit0  Bit1  Bit2  Bit3   Bit4      Bit5    Bit6  Bit7
          
            ```
          
            **What shifted:**
          
            - Output Bit 4: `P1 Alarm` → **P1 SCV** (alarm pushed to Bit 5)
          
            - Output Bit 5: `—` → **P1 Alarm** (shifted right by 1)
          
            - IS and AC inputs: unchanged (CVs don't affect input mapping)
          
            ---
          
            ## Maximum Configurations Before Overflow
          
            | Products | Max Turbines | Max CVs (with per-product alarm) | Max CVs (with combined alarm) | Max CVs (no alarm) |
          
            |:--------:|:------------:|:--------------------------------:|:-----------------------------:|:-------------------:|
          
            | 1        | 4            | 3                                | 3*                            | 4                   |
          
            | 2        | 4            | 2                                | 3                             | 4                   |
          
            *With 1 product, "combined" is the same as "individual" since there's only 1 alarm output needed.
          
            **Hard limits:**
          
            - Total turbines: 4 (limited by `N_ISM`)
          
            - Total turbines + total CVs + alarm outputs must fit in 4 bits (bits 4-7)
          
            - Total piston switches must be <= 8 (limited by `N_INPUTS`, typically = total turbines)
          
            - Total turbines must be <= 4 for auth inputs (limited by `N_AUTH_INPUTS`); at 4, Reset All is lost
          
            ---
          
            ## Configuration Variables That Drive I/O Shifts
          
            | Variable (per product)    | Affects Outputs           | Affects IS Inputs    | Affects AC Inputs      |
          
            |---------------------------|---------------------------|----------------------|------------------------|
          
            | `N_Turbines`              | Turbine bits 0 to T-1    | —                    | Auth bits 0 to T-1     |
          
            | `N_PistonSwitches`        | —                         | IS bits 0 to PS-1    | —                      |
          
            | `CV.SCV` (count)          | CV bits, shifts alarms    | —                    | —                      |
          
            | `CV.PCV` (count)          | CV bits, shifts alarms    | —                    | —                      |
          
            | `CV.DCV` (count)          | CV bits, shifts alarms    | —                    | DCV demand shares auth |
          
            | `N_Products` (global)     | Alarm bit count           | —                    | Reset All availability |
          
            ---
          
            ## Source Code References
          
            | Function / File              | What it controls                         |
          
            |------------------------------|------------------------------------------|
          
            | `ChannelSetup()` in `PLC.c`  | IOPS assignment, CV IO channel positions |
          
            | `WriteOutputs()` in `plc_outputs.lib` | Output bit writing logic        |
          
            | `InputHandler()` in `plc_inputs.lib`  | Input scanning and flag setting  |
          
            | `InitChannel()` in `plc_configuration.lib` | Default IOChannel = channel index |
          
            | Constants in `plc_constants.lib` | `CV_OFFSET=4`, `N_OUTPUTS=8`, `SUMP_OFFSET=0`, etc. |

1	# PLC-5000 I/O Site Configuration Matrix
2
3	## Hardware Constraints
4
5	\| Resource \| Max \| Define \|
6	\|-------------------\|-----\|----------------\|
7	\| Output Bits \| 8 \| `N_OUTPUTS` \|
8	\| IS Input Bits \| 8 \| `N_INPUTS` \|
9	\| AC Input Bits \| 8 \| `N_AC_INPUTS` \|
10	\| Channels/Turbines \| 4 \| `N_ISM` \|
11	\| Products \| 4 \| `N_PROD` \|
12	\| Piston Switches \| 4 \| `N_PRES_INPUTS`\|
13	\| Auth Inputs \| 4 \| `N_AUTH_INPUTS` \|
14
15	Compile-time flags assumed (current defaults from `PLC.c`):
16	- `MODBUS_M_ON = 1` (LDN pressure via Modbus master)
17	- `ALARM_PER_PROD = 1` (one alarm output per product, not per channel)
18	- `CV_ON = 1` (control valves enabled)
19	- `RESET_ALL_INPUT = 1` (last free AC input = Reset All)
20	- `DISABLE_INPUT = 0` (auth inputs are NOT used as disable)
21
22	---
23
24	## General Output Mapping Formula (Bits 0-7)
25
26	```
27	Bit Range \| Function
28	------------------------------------\|--------------------------------------------
29	0 to T-1 \| Turbine Pump outputs (1 per turbine)
30	T to 3 \| UNUSED (gap if T < 4)
31	4 to 4+C-1 \| Control Valve outputs (CV_OFFSET = 4)
32	4+C to 4+C+P-1 \| Alarm outputs (1 per product)*
33	```
34
35	Where:
36	- T = total turbines across all products (`Config.N_Turbines`)
37	- C = total control valves across all products (`Config.N_CVs` = sum of all SCV+PCV+DCV)
38	- P = number of products (`Config.N_Products`)
39
40	### CV Output Sub-ordering (within the CV range)
41
42	For each product sequentially:
43	1. SCV (Solenoid Control Valves) first
44	2. PCV (Pressure Control Valves) next
45	3. DCV (Demand Control Valves) last
46
47	```
48	Product 0 SCVs → Product 0 PCVs → Product 0 DCVs → Product 1 SCVs → Product 1 PCVs → ...
49	```
50
51	### Alarm Output Overflow Rules
52
53	\| Condition \| Behavior \|
54	\|----------------------------\|-----------------------------------------------\|
55	\| `C <= 4 - P` \| Individual alarm output per product at bit 4+C+i \|
56	\| `4 - P < C < 4` \| Combined alarm for all products at bit 7 \|
57	\| `C >= 4` \| NO alarm output (all output bits consumed by CVs) \|
58
59	Source: `WriteOutputs()` in `plc_outputs.lib`
60
61	---
62
63	## General Input Mapping Formula
64
65	### IS Inputs (Intrinsically Safe - `Inputs[]` array)
66
67	```
68	Bit Range \| Function
69	------------------\|--------------------------------------------------
70	0 to PS-1 \| Sump Sensor + High Pressure Switch (per piston switch)
71	PS to 7 \| UNUSED
72	```
73
74	Where PS = total piston switches across all products (`Config.N_PS`).
75
76	Each piston switch gets one IS input. Turbines within a product that exceed the piston switch count share the previous turbine's IS input (via `Channel[j].IOPS`).
77
78	With `MODBUS_M_ON = 1`:
79	- Primary pressure readings come from LDN sensors via Modbus, NOT from IS inputs
80	- The IS input serves as: Sump sensor (if `NoSumpFlag = 0`) AND high pressure switch confirmation
81	- Both use the same physical input bit (`SUMP_OFFSET = 0`)
82
83	### AC Inputs (Authorization - `AC_Inputs[]` array)
84
85	```
86	Bit Range \| Function
87	------------------\|--------------------------------------------------
88	0 to T-1 \| Authorization input (1 per turbine/channel)
89	T to 2 \| UNUSED (if T < 3)
90	3 \| Reset All* (if T < 4)
91	4 to 7 \| UNUSED
92	```
93
94	Where T = total turbines.
95
96	Reset All is only available when `Config.N_Turbines < N_AUTH_INPUTS (4)` and `RESET_ALL_INPUT = 1`. It uses `AC_Inputs[3]` (index `AUTH_OFFSET + N_AUTH_INPUTS - 1`).
97
98	DCV Demand Note: When a product has DCVs, the AC auth inputs for that product's turbines also serve as DCV demand signals. `ACInputs[Product[i].FirstTurbine + j]` controls `DCV[j]`. The same physical signal that authorizes a turbine also opens its corresponding DCV.
99
100	---
101
102	## Output Matrix by Site Configuration (Max 2 Products)
103
104	### Legend
105	- P1T1 = Product 1, Turbine 1 Pump output
106	- P1-SCV1 = Product 1, Solenoid Control Valve 1
107	- P1-ALM = Product 1, Alarm output
108	- COMBINED-ALM = Shared alarm output for all products
109	- `—` = Unused
110
111	### 1-Product Configurations
112
113	\| Output Bit \| 1P/1T/0CV \| 1P/2T/0CV \| 1P/2T/1SCV \| 1P/2T/1S+1P \| 1P/3T/0CV \| 1P/4T/0CV \| 1P/4T/1SCV \| 1P/4T/2SCV \| 1P/4T/3SCV \|
114	\|:----------:\|:---------:\|:---------:\|:----------:\|:------------:\|:---------:\|:---------:\|:----------:\|:----------:\|:----------:\|
115	\| 0 \| P1T1 \| P1T1 \| P1T1 \| P1T1 \| P1T1 \| P1T1 \| P1T1 \| P1T1 \| P1T1 \|
116	\| 1 \| — \| P1T2 \| P1T2 \| P1T2 \| P1T2 \| P1T2 \| P1T2 \| P1T2 \| P1T2 \|
117	\| 2 \| — \| — \| — \| — \| P1T3 \| P1T3 \| P1T3 \| P1T3 \| P1T3 \|
118	\| 3 \| — \| — \| — \| — \| — \| P1T4 \| P1T4 \| P1T4 \| P1T4 \|
119	\| 4 \| P1-ALM \| P1-ALM \| P1-SCV1 \| P1-SCV1 \| P1-ALM \| P1-ALM \| P1-SCV1 \| P1-SCV1 \| P1-SCV1 \|
120	\| 5 \| — \| — \| P1-ALM \| P1-PCV1 \| — \| — \| P1-ALM \| P1-SCV2 \| P1-SCV2 \|
121	\| 6 \| — \| — \| — \| P1-ALM \| — \| — \| — \| P1-ALM \| P1-SCV3 \|
122	\| 7 \| — \| — \| — \| — \| — \| — \| — \| — \| COMB-ALM \|
123
124	### 2-Product Configurations
125
126	\| Output Bit \| 2P/1+1T/0CV \| 2P/1+1T/1+1SCV \| 2P/2+1T/0CV \| 2P/2+2T/0CV \| 2P/2+2T/1+1SCV \|
127	\|:----------:\|:-----------:\|:---------------:\|:-----------:\|:-----------:\|:---------------:\|
128	\| 0 \| P1T1 \| P1T1 \| P1T1 \| P1T1 \| P1T1 \|
129	\| 1 \| P2T1 \| P2T1 \| P1T2 \| P1T2 \| P1T2 \|
130	\| 2 \| — \| — \| P2T1 \| P2T1 \| P2T1 \|
131	\| 3 \| — \| — \| — \| P2T2 \| P2T2 \|
132	\| 4 \| P1-ALM \| P1-SCV1 \| P1-ALM \| P1-ALM \| P1-SCV1 \|
133	\| 5 \| P2-ALM \| P2-SCV1 \| P2-ALM \| P2-ALM \| P2-SCV1 \|
134	\| 6 \| — \| P1-ALM \| — \| — \| P1-ALM \|
135	\| 7 \| — \| P2-ALM \| — \| — \| P2-ALM \|
136
137	---
138
139	## IS Input Matrix by Site Configuration
140
141	Assumes `N_PistonSwitches = N_Turbines` per product (typical).
142
143	### 1-Product Configurations
144
145	\| IS Input Bit \| 1P/1T \| 1P/2T \| 1P/3T \| 1P/4T \|
146	\|:------------:\|:-----:\|:-----:\|:-----:\|:-----:\|
147	\| 0 \| Sump/HiPres 1 \| Sump/HiPres 1 \| Sump/HiPres 1 \| Sump/HiPres 1 \|
148	\| 1 \| — \| Sump/HiPres 2 \| Sump/HiPres 2 \| Sump/HiPres 2 \|
149	\| 2 \| — \| — \| Sump/HiPres 3 \| Sump/HiPres 3 \|
150	\| 3 \| — \| — \| — \| Sump/HiPres 4 \|
151	\| 4-7 \| — \| — \| — \| — \|
152
153	### 2-Product Configurations
154
155	\| IS Input Bit \| 2P/1+1T \| 2P/2+1T \| 2P/2+2T \| 2P/1+3T \| 2P/3+1T \|
156	\|:------------:\|:-------:\|:-------:\|:-------:\|:-------:\|:-------:\|
157	\| 0 \| P1-Sump/HiPres \| P1-Sump/HiPres 1 \| P1-Sump/HiPres 1 \| P1-Sump/HiPres \| P1-Sump/HiPres 1 \|
158	\| 1 \| P2-Sump/HiPres \| P1-Sump/HiPres 2 \| P1-Sump/HiPres 2 \| P2-Sump/HiPres 1 \| P1-Sump/HiPres 2 \|
159	\| 2 \| — \| P2-Sump/HiPres \| P2-Sump/HiPres 1 \| P2-Sump/HiPres 2 \| P1-Sump/HiPres 3 \|
160	\| 3 \| — \| — \| P2-Sump/HiPres 2 \| P2-Sump/HiPres 3 \| P2-Sump/HiPres \|
161	\| 4-7 \| — \| — \| — \| — \| — \|
162
163	---
164
165	## AC Input Matrix by Site Configuration
166
167	### 1-Product Configurations
168
169	\| AC Input Bit \| 1P/1T \| 1P/2T \| 1P/3T \| 1P/4T \|
170	\|:------------:\|:-----:\|:-----:\|:-----:\|:-----:\|
171	\| 0 \| Auth T1 \| Auth T1 \| Auth T1 \| Auth T1 \|
172	\| 1 \| — \| Auth T2 \| Auth T2 \| Auth T2 \|
173	\| 2 \| — \| — \| Auth T3 \| Auth T3 \|
174	\| 3 \| Reset All \| Reset All \| Reset All \| Auth T4 \|
175	\| 4-7 \| — \| — \| — \| — \|
176
177	### 2-Product Configurations
178
179	\| AC Input Bit \| 2P/1+1T \| 2P/2+1T \| 2P/2+2T \| 2P/1+3T \| 2P/3+1T \|
180	\|:------------:\|:-------:\|:-------:\|:-------:\|:-------:\|:-------:\|
181	\| 0 \| P1-Auth T1 \| P1-Auth T1 \| P1-Auth T1 \| P1-Auth T1 \| P1-Auth T1 \|
182	\| 1 \| P2-Auth T1 \| P1-Auth T2 \| P1-Auth T2 \| P2-Auth T1 \| P1-Auth T2 \|
183	\| 2 \| — \| P2-Auth T1 \| P2-Auth T1 \| P2-Auth T2 \| P1-Auth T3 \|
184	\| 3 \| Reset All \| Reset All \| P2-Auth T2 \| P2-Auth T3 \| P2-Auth T1 \|
185	\| 4-7 \| — \| — \| — \| — \| — \|
186
187	Key observations:
188	- Reset All is available at AC Input 3 ONLY when total turbines < 4
189	- When total turbines = 4, ALL AC inputs are consumed by auth — no Reset All available
190	- With `DISABLE_INPUT = 1` (not current default), the last turbine's AC input in each product becomes a disable input instead of auth
191
192	---
193
194	## How Shifting Works — Walkthrough
195
196	### Example: Adding a 2nd product to a 1-product / 2-turbine / 1-SCV site
197
198	Before (1P/2T/1SCV):
199	```
200	OUTPUTS: [P1T1][P1T2][ — ][ — ][P1-SCV][ P1-ALM ][ — ][ — ]
201	Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7
202
203	IS: [Sump1][Sump2][ — ][ — ][ — ][ — ][ — ][ — ]
204	Bit0 Bit1 ...
205
206	AC: [Auth1][Auth2][ — ][RESET][ — ][ — ][ — ][ — ]
207	Bit0 Bit1 Bit2 Bit3 ...
208	```
209
210	After adding Product 2 (1 turbine, 1 SCV) → 2P / 2+1T / 1+1SCV:
211	```
212	OUTPUTS: [P1T1][P1T2][P2T1][ — ][P1-SCV][P2-SCV][ P1-ALM ][ P2-ALM ]
213	Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7
214
215	IS: [P1-Sump1][P1-Sump2][P2-Sump1][ — ][ — ][ — ][ — ][ — ]
216	Bit0 Bit1 Bit2 ...
217
218	AC: [P1-Auth1][P1-Auth2][P2-Auth1][RESET][ — ][ — ][ — ][ — ]
219	Bit0 Bit1 Bit2 Bit3 ...
220	```
221
222	What shifted:
223	- Output Bit 2: `—` → P2 Turbine 1 Pump
224	- Output Bit 5: `P1 Alarm` → P2 SCV (P1 Alarm pushed to Bit 6)
225	- Output Bit 6: `—` → P1 Alarm (shifted right by 1 due to new CV)
226	- Output Bit 7: `—` → P2 Alarm (new)
227	- IS Input Bit 2: `—` → P2 Sump/HiPres
228	- AC Input Bit 2: `—` → P2 Auth T1
229
230	### Example: Adding a CV to an existing product
231
232	Before (1P/2T/0CV):
233	```
234	OUTPUTS: [P1T1][P1T2][ — ][ — ][ P1-ALM ][ — ][ — ][ — ]
235	Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7
236	```
237
238	After adding 1 SCV → 1P/2T/1SCV:
239	```
240	OUTPUTS: [P1T1][P1T2][ — ][ — ][ P1-SCV ][ P1-ALM ][ — ][ — ]
241	Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7
242	```
243
244	What shifted:
245	- Output Bit 4: `P1 Alarm` → P1 SCV (alarm pushed to Bit 5)
246	- Output Bit 5: `—` → P1 Alarm (shifted right by 1)
247	- IS and AC inputs: unchanged (CVs don't affect input mapping)
248
249	---
250
251	## Maximum Configurations Before Overflow
252
253	\| Products \| Max Turbines \| Max CVs (with per-product alarm) \| Max CVs (with combined alarm) \| Max CVs (no alarm) \|
254	\|:--------:\|:------------:\|:--------------------------------:\|:-----------------------------:\|:-------------------:\|
255	\| 1 \| 4 \| 3 \| 3* \| 4 \|
256	\| 2 \| 4 \| 2 \| 3 \| 4 \|
257
258	*With 1 product, "combined" is the same as "individual" since there's only 1 alarm output needed.
259
260	Hard limits:
261	- Total turbines: 4 (limited by `N_ISM`)
262	- Total turbines + total CVs + alarm outputs must fit in 4 bits (bits 4-7)
263	- Total piston switches must be <= 8 (limited by `N_INPUTS`, typically = total turbines)
264	- Total turbines must be <= 4 for auth inputs (limited by `N_AUTH_INPUTS`); at 4, Reset All is lost
265
266	---
267
268	## Configuration Variables That Drive I/O Shifts
269
270	\| Variable (per product) \| Affects Outputs \| Affects IS Inputs \| Affects AC Inputs \|
271	\|---------------------------\|---------------------------\|----------------------\|------------------------\|
272	\| `N_Turbines` \| Turbine bits 0 to T-1 \| — \| Auth bits 0 to T-1 \|
273	\| `N_PistonSwitches` \| — \| IS bits 0 to PS-1 \| — \|
274	\| `CV.SCV` (count) \| CV bits, shifts alarms \| — \| — \|
275	\| `CV.PCV` (count) \| CV bits, shifts alarms \| — \| — \|
276	\| `CV.DCV` (count) \| CV bits, shifts alarms \| — \| DCV demand shares auth \|
277	\| `N_Products` (global) \| Alarm bit count \| — \| Reset All availability \|
278
279	---
280
281	## Source Code References
282
283	\| Function / File \| What it controls \|
284	\|------------------------------\|------------------------------------------\|
285	\| `ChannelSetup()` in `PLC.c` \| IOPS assignment, CV IO channel positions \|
286	\| `WriteOutputs()` in `plc_outputs.lib` \| Output bit writing logic \|
287	\| `InputHandler()` in `plc_inputs.lib` \| Input scanning and flag setting \|
288	\| `InitChannel()` in `plc_configuration.lib` \| Default IOChannel = channel index \|
289	\| Constants in `plc_constants.lib` \| `CV_OFFSET=4`, `N_OUTPUTS=8`, `SUMP_OFFSET=0`, etc. \|