Jump to content

Computer Automated Measurement and Control

From Wikipedia, the free encyclopedia
This is an old revision of this page, as edited by Ohconfucius (talk | contribs) at 03:31, 20 November 2013 (per MOS:CAPS). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
A CAMAC module made by LeCroy

Computer Automated Measurement snd Control (CAMAC) is a standard bus and modular crate electronics standard for Data acquisition and control used in nuclear and particle physics experiments and in industry. The bus allows data exchange between plug-in modules (up to 24 in a single crate) and a crate controller, which then interfaces to PC or to a VME-CAMAC interface.

The standard was originally defined by the ESONE Committee[1] as standard EUR 4100 in 1972,[2] and covers the mechanical, electrical and logic of a parallel bus (dataway) for the plug-in modules. Several standards have been defined for multiple crate systems including the Parallel Branch Highway definition and Serial Highway definition. Vendor specific Host/Crate interfaces have also been built.

The CAMAC standard encompasses IEEE standards:

Within the dataway, modules are addressed by slot (Geographical addressing). The left-most 22 slots are available for application modules while the right-most two slots are dedicated to a crate controller. Within a slot the standard defines 16 subaddresses (0–15). A slot commanded by the controller with one of 32 function codes (0–31). Of these function codes, 0–7 are read functions and will transfer data to the controller from the addressed module, while 16–23 are write function codes which will transfer data from the controller to the module.

In addition to functions that address the module, the following global functions are defined:

  • I – Crate inhibit
  • Z – Crate zero.
  • C – Crate clear.

The original standard was capable of one 24 bit data transfer every microsecond. Later a revision to the standard was released to support short cycles which allow a transfer every 450ns. A follow on upwardly compatible standard Fast CAMAC allows the crate cycle time to be tuned to the capabilities of the modules in each slot.

The FASTBUS standard was introduced in 1984 as a replacement for CAMAC in large systems.

Backplane physical characteristics

The physical connector on the back of a CAMAC module is a card-edge connector, with a receiving socket on the backplane. Because there are no alignment pins on the socket or connector, there is the possibility of connector mis-alignment upon module insertion. Therefore, CAMAC modules may NOT be hot-swapped.

Backplane electrical characteristics

CAMAC shares low-voltage DC voltages with NIM crates. The crate supplies +6V, -6V, +12V, -12V, +24V, and -24V to all modules.

See also

References

  1. ^ The ESONE committee
  2. ^ http://www.cern.ch/ESONE/hibernation.pdf ESONE letter


Stub icon

This computer hardware article is a stub. You can help Wikipedia by expanding it.

Stub icon

This particle physics–related article is a stub. You can help Wikipedia by expanding it.

Retrieved from "https://en.wikipedia.org/w/index.php?title=Computer_Automated_Measurement_and_Control&oldid=582472702"