The Jorway Model 174 Type L-2 Serial Crate Controller interfaces the dataway of a CAMAC crate with the CAMAC Serial Highway, fully complying with the CAMAC Standards 583 and 595. This controller while supplying all the features of type L-2 controllers as do other Jorway serial controllers such as the Model 74B Type L-2 and the Model 74RG Request-Grant Type L-2, contains special features allowing high speed block transfer modes with data throughput far in excess of normal type L-2 controllers.

The IEEE Standard 595 defines the message protocol for all devices which use the CAMAC Serial Highway. While the Type L-2 controller conforms to this protocol, other protocols are permitted under the broader requirements of the 595 standard. The Model 174 supports an additional protocol of block transfer modes where the data portion of a message is expanded so 24 bit data blocks can be transfered to the controller at rates up to 24 bits every microsecond ( 3 megabytes per second in byte serial at 5MHz ). A crystal controlled dataway timing generator allows dataway cycles to occur every mircosecond, the highest speed allowed by the 583 standard. The Model 174 can perform as a normal type L-2 but can also operate in this ultra high speed block made where applications dictate the need. Other type L-2 controllers can be mixed on the same serial highway as long as block operations are addressed only to controllers with that capability. The host computer and CAMAC interface must also be capable of supporting block operations at this speed.

The block operations are normally performed at one specific station N and subaddress A ( Modules such as transient recorders or memory modules ). Blocks are also for a specific function code F usually either read blocks or write blocks. Provision is made in the Model 174 for connection from a 14 pin front panel auxilliary connector to a List Mode Module. This List Mode Module allows random NAF operations to be performed at block speeds from preloaded lists stored in the List Mode Module. The auxillary connector and controller signals support the Jorway Model 272 and Kinetic Systems Model 3952 List Mode Modules.

U-PORT ADAPTERS

With high quality, cable serial crate controllers can be seperated by distances up to 400 feet when operating a the 5 MHz serial clock rate. Proportionately longer distances can be achieved at lower clock rates. The standard serial highway twisted pair wiring is usually quite adequate in most applications especially within crates in the same proximity. For applications in noisy environments and requiring a voltage break we suggest third party fiber optic U-port Adapters such as LeCroy Type 5211 or Kinetic Systems Model 3939. In bit serial applications where ground isolation is required, the Jorway Model 76 Opto-isolated Bypass Module offers a very economical solution.

 OPTIONS
 Auxilliary Controller Configeration: Option 1 provides an array of switches at the rear 
   panel which will allow the Model 174 controller to operate as an auxilliary crate controller.

High Magnetic Field Operation: Option 2 provides special relays in place of the normal 
    reed relays which will provide for operation of the functions of Bypass and
   Loop Collapse in magnetic fields up to 150 gauss.

 CONTROLLER CHARACTERISTICS
 Controls:
   Front Panel Switches On/Off Line, Manual C and Z, and Crate Address Selection.
   Internal Switches Bit/Byte Mode and Block Mode Enable/Disable switches accessable 
at top of module. PCB switch for Demand Timer selection in range 1ms to 10 seconds.
 Indicators: (* indication is "stretched" so short duration signals are visable)
   On Line Controller is in the On Line state.
   Lost Sync * Controller is not synchronized (Byte or Bit).
   Addressed * Controller has accepted a command addressed to it, and is engaged in a
 command-reply transaction.
   Error A parity error has been detected while receiving a message addressed to it.
   Bypass Bypass Status Register bit is set and controller is in the bypass state.
   I Dataway Inhibit (I) line is at a logic "1".
   DMI Demand Message Initiate input is at logic "1".
   Bit On Indicates Bit/Byte select switch is selected for the Bit Mode.

 Connectors: Serial Highway D Port Input (DB-25P) and D Port Output (DB-25S)
 SGL (2DB52P), LAM encoding/generation and auxilliary controller interface.
 Auxilliary, front panel 19 Pin ribbon type for serial clock and data
 monitoring and List Mode Module interface signals.

Commands at N(30):		Normal		Off Line		Bypassed
		SQ	SX	SQ	SX	SQ	SX
Standard L-2 Commands
Reread Previous Read Field	F(O) A(l)	DSQ	1	DSQ	0	1	0
Read Status Register	F(l) A(O)	1	1	0	0	1	0
Read LAM Pattern	F(l) A(12)	DSQ	1	DSQ	0	1	0*
Write Status Register	F(17)A(O)	1	1	0	0	1	0
Selective Set Status Register	F(19)A(O)	1	1	0	0	1	0*
Selective Clear Status Register	F(23)A(O)	1	1	0	0	1	0
List Mode Commands (Command for List Mode Module)
Select NAF list 0	F(12)A(O)	1	1	0	0	1	0
Select NAF list 1	F(12)A(l)	1	1	0	0	1	0
Select NAF list 2	F(12)A(2)	1	1	0	0	1	0
Select NAF list 3	F(12)A(3)	1	1	0	0	1	0
*, X=l at clear Bypass