Option F4A - Isolated Parellel BCD upper board, Three-state with 1-Bit Enable

ISOLATED PARALLEL BCD UPPER BOARD, THREE-STATE WITH 1-BIT ENABLE
OPTION F4A

BCD OUTPUT

Buffered

Isolated

Stored

Three-state

APPLICABLE INSTRUMENTS

Models 204B, 2003B and 2004 for DC, AC, true-RMS or process signals

Models 267B and 268 for thermocouple or RTD temperature signals

DEVICE ADDRESSING
Single-line enable

The F4A is an upper-board option which provides buffered, isolated, stored, three-state parallel BCD output plus an enable line for addressing in data busing applications. The six panel meters which accept the F4A option also provide a separate non-buffered, non-isolated parallel BCD output, which is a standard feature of the main board.

Buffering the output allows the F4A to drive 12 TTL loads in electrically-noisy environments without affecting correct operation of the host panel meter.

Isolation of all digital I/O lines eliminates ground loops and allows the analog input to the meter to float up to 350 V with respect to BCD ground. Isolated operation requires that an external 5 V dc, 100 mA power supply be used
Storing the BCD data assures that correct BCD data is always available, regardless of the current state of A/D conversion.

Three-state drivers allow all output lines to be put in a logical "0", logical "1", or high-impedance state. The high-impedance state does not load down the external circuit and allows multiple F3A's to be bused with all BCD lines in parallel.

SEPARATE BCD AND METER HOLD
The F4A provides separate BCD and meter HOLD functions. In F4A BCD HOLD, the display and non-isolated BCD output of the main board continue to update while the BCD output of the F4A remains latched. For instance, the non-isolated BCD can be used as an uninterrupted input to a Model 872A dual-setpoint controller while the isolated BCD of the F4A is on HOLD.

ENABLE-LINE ADDRESSING
The F4A provides an enable line, which can take the BCD output drivers out of the high-impedance state. This line allows a specific panel meter on a BCD bus to be selected by a programmable controller using simple single-line addressing. As a failsafe feature, an open enable line will automatically return the BCD outputs to their high-impedance state.

SPECIFICATIONS

CONTROL-LOGIC INPUTS
Logical "0": 0 to 0.5 V
Logical "1": 2.4 to 5.5 V
Input load: 0.5 TTL unit loads at 5 V

BCD AND CONTROL-LOGIC OUTPUTS
Logical "0": 0 to 0.5 V
Logical "1": 2.4 to 5.25 V
Output drive: 12 TTL unit loads at 5 V
Hi-Z state: 20 µA leakage at 2.4 V

POWER
DC voltage: 5 V dc ±5%, 50 mA
DC current: 100 mA (nominal)
Power consumption: 0.5 W (nominal)
Isolation, power to BCD lines: 350 Vp

ENVIRONMENTAL
Operating temperature: 0 to 50°C
Storage temperature: -40 to +85°C
Relative humidity: 95% at 40°C(non-condensing)

MECHANICAL
Form factor: Newport DIN 1A upper board
Dimensions: 3.35 x 4.69 in (85 x 119 mm)
Connector: 36-pin, double-row, solder-type