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:
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