> For the complete documentation index, see [llms.txt](https://help.security.gallagher.com/knowledge-hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.security.gallagher.com/knowledge-hub/products/cc-hardware/controllers/controller-6000/reference/controller-6000-limits.md).

# Controller 6000 limits

Reference Controller 6000 capacity, cabling, device, alarm, and configuration limits.

Capacities, cabling distances, and per-device limits for the C6000 controller. For a side-by-side capacity comparison with the C7000, see [Controller 7000 - Limits](/knowledge-hub/products/cc-hardware/controllers/controller-7000-and-7000-sdc/reference/controller-7000-limits.md).

***

## Cabling distances

| Bus         | Maximum distance |
| ----------- | ---------------- |
| GBUS wiring | 1,220 metres     |
| HBUS wiring | 500 metres       |

***

## Controller parts limits

| Controller | Typical parts       |
| ---------- | ------------------- |
| C6000      | 1,500 typical parts |

"Typical parts" describes the average part memory usage. Heavy-weight parts consume more memory. Lighter parts occupy less memory.

If the controller is expected to have minimum down time, consider the configuration time and startup time of a controller.

***

## Network controller connections

| Direction            | Limit |
| -------------------- | ----- |
| Incoming connections | 60    |
| Outgoing connections | 60    |

***

## Controller configuration size

There is a **16,384 bytes (16 KB)** limit on the configuration record size. If this is exceeded, an alarm `Configuration over-sized for Controller {x}` is generated.

All configuration sent to a controller (per part, or for the controller itself) must fit within this 16 KB limit.

> ⚠️ **As of v7.80**, this limit increased to **65,535 bytes (64 KB)** to allow a larger `BertConfigT` message. Because the size of a record is represented by a word (uint16), the BertBus protocol would have to change to support further size increases.

> **Note:** This only applies to BertBus messages. The flash database is still limited by the 16 KB record size.

***

## Alarms per controller

| Mode    | Active alarm limit | Behaviour at limit     |
| ------- | ------------------ | ---------------------- |
| Release | 100 active alarms  | Starts dropping alarms |
| Debug   | 15 active alarms   | (Reduced for testing)  |

A controller keeps an alarm history of 500 alarms.

***

## Anti-Passback

A maximum of **32,000 cards** are stored in anti-passback lists per controller.

***

## HBUS

A maximum of **20 readers per controller**.

**HBUS Connections - PIV (High Sec):** a maximum of **80 HBUS devices** may be connected to a single High Sec controller, shared over all HBUS Ports. Each device type also has its own limit.

***

## Inter-controller monitoring

**30 monitored controllers** per monitoring controller.

***

## Aperio

| Limit                               | Value |
| ----------------------------------- | ----- |
| Maximum Aperio doors per Bus        | 16    |
| Maximum Aperio doors per Controller | 20    |

***

## Moduteq

| Limit                        | Value |
| ---------------------------- | ----- |
| Maximum devices per bus      | 16    |
| Maximum buses per controller | 4     |

***

## Schlage

| Limit                                          | Value |
| ---------------------------------------------- | ----- |
| Maximum Schlage PIMs per bus                   | 8     |
| Maximum Schlage Doors per bus                  | 16    |
| Maximum Schlage Devices per bus (Doors + PIMs) | 24    |
| Maximum Schlage PIMs per controller            | 8     |
| Maximum Schlage Doors per controller           | 16    |
| Maximum Schlage Devices per controller         | 24    |

***

## Controller performance recommendations

Avoid exceeding an expected **5 events per second per controller**.

***

🔗 **Related**

* [Controller 7000 - Limits](/knowledge-hub/products/cc-hardware/controllers/controller-7000-and-7000-sdc/reference/controller-7000-limits.md). Full capacity comparison table across C6000 and C7000.
* [Controller 6000](/knowledge-hub/products/cc-hardware/controllers/controller-6000.md). Variants, accessories, and lifecycle.


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