The A166TB is a printed circuit board that contains a 50 pin (2 rows of 25 pins each) male connector for ribbon cable and 50 terminal blocks.  The board measures 8.5" x 3-3/16" a 1" H and can be mounted in a track in any position. The terminal blocks are barrier type strips for up to four 18AWG or two 14 AWG wires each.

The A166TB is extensively used to provide a terminal block connection for the BCD output and other signals of the A169LD/1 load cell digitizer.  This permits running a 50 conductor ribbon cable from the A169LD/1 to a A166TB installed in a convenient location on the back panel, then hard wiring the A166TB to PLC   I/O, other devices  or field wiring.  The A166TB may be used with other compatible instruments and meters.

The A166TB has provisions for installing diodes on the component side of the board for terminals 1 thru 30.  Two options are available on the A166TB, depending on the polarity of the diodes.  When diodes are installed, the circuit side of the board must be cut.  See circuit side below.

When used with A166LD/1 digitizer in the  BCD output mode, the A166TB provides the following signals:

A169LD/1              A166TB                                                    A169LD/1               A166TB
    D1B1 (LSB)              6                                                                D3B4                              7
    D1B2                       10                                                                D3B8                            16
    D1B4                         8                                                                D4B1                            13
    D1B8                       12                                                                D4B2                            22
    D2B1                         2                                                                D4B4                            11
    D2B2                         5                                                                D4B8                            20
    D2B4                         1                                                                D5B1                            44
    D2B8                         3                                                                D5B2                            50
    D3B1                         9                                                                D5B4                            48
    D3B2                       18                                                                D5B8 (MSB)                46
    TARE                       17                                                                HOLD                           32  
    CHECK                   19                                                                CENTER OF ZERO    33 
    NET/GROSS           21                                                               NEGATIVE                   37
    LB/KG (FUTURE)   23                                                               GROSS/NET                39
    VALID                      24                                                                DIGITAL GROUND      43
    OVERLOAD           26                                                                OUTPUT DISABLE      49
    LB/KG                     31

NOTE:  Terminals 4,14,15, 25, 27, 28, 29, 30, 34, 35, 36, 38, 40, 41, 42, 45,AND 47 are not used.

Active levels of the signals to/from the A169LD/1 are indicated with the convention of positive true logic.  That is, signals that are underlined are active for a low level, while others are active at a high level.

The above signals fall into one of three groups: Data Values, Status Signals and Control Signals. Please refer to the A169LD instruction manual for more complete information.

A.  Data Values are binary related components (B1, B2, B4, B8) of each digit (D1-LSD, D2, D3, D4,          D5-MSD) in the five digit value.  In addition there is one line dedicated to the polarity (Negative).

B.   Status Signals are mode indicators of front panel functions and information LB/KG, GROSS/NET, CENTER OF ZERO and OVERLOAD (FFFF etc.).  In addition VALID is a status signal of "DATA VALID" that is active Low when the tri-state output ports have been updated with a just completed conversion'

C.   Control Signals are active low and remain inactive unless used.  HOLD inhibits change in output data and holds the last reading until released.  LB/KG is a future software modification.  Tare is a toggle function as is NET/GROSS  and CHECK .  In addition OUTPUT DISABLE puts the status and data values into the tri-state mode when driven high.  This forces the bus to a high impedance state but sequential operation of conversion is not inhibited.                                                                                                  
                                                      
                                                             A166 TB TERMINAL BOARD