Up to a higher level directory | | For more information
The Jorway model 176 Series Bypass devices are single width CAMAC modules that provide the ability to bypass type L-2 Serial Crate controllers operating in the Byte serial mode. All ports operate in the normal CAMAC signal transmission standard EIA 422 eliminating the need for costly non-CAMAC standard transmission U port converters. The serial highway may operate from DC to 5MHz without adjustment of any components and the frequency can be varied at will. Bypass is controlled by the bypass relay in the type L-2 controller. As a result of power down of the crate and controller, the model 176 will provide "bypass", channeling the serial D port highway input signals directly to the serial D port highway outputs. In addition, relays in the Model 176 provide for switching out the 100 Ohm line to line highway terminations when "Bypass" is in effect. The serial highway signal inputs are buffered by differential receivers within the Model 176 to eliminate the 100 ohm termination of the L-2 from being seen by the bypassed highway.
The Model 176 series Bypass Module is available in a number of versions.
MODEL 176 and 176-1. The standard model 176 is an optical isolated unit which, in addition to providing bypass for the serial crate controller, also provides electrical isolation between adjacent crates on the CAMAC serial highway. High speed optical isolators are inserted in both the clock and data paths, powered by on-board DC-DC converters. The Model 176 provides isolation to the D-Input and D-Output ports. The 176-1 module is employed in the last Crate on the Serial Highway, thereby isolating the Serial Highway Driver itself. In the "Bypassed" state the Serial Highway "Earth" is continuous, with no ohmic connection to the bypassed crate. The bypassed Crate continually monitors the Serial Highway message traffic, via optical isolators, so that it can be un-bypassed by a suitable message.
MODEL 176-R. The model 176-R is identical to the Model 176 but does not provide optical isolation. The serial highway cable ground and the serial crate controller ground are common.
Installation of these modules is extremely simple, and requires no additional cables to be fabricated. The Bypass module is placed in any vacant slot in the CAMAC Crate. The incoming and outgoing Serial Highway cables are moved from the Crate Controller to equivalent connectors on the front panel of the Bypass Module. Short cables that are captive to the Bypass Module are connected to the Crate Controller. No other changes to the system are required.