DESCRIPTION AND OPERATION
HSS MODULE CIRCUITRY
2 - 6
I-E96-322A
®
The MFP module sends the following information and com-
mands to the HSS module by way of the I/O expander bus
interface:
•
Position demand.
•
LVDT frequency.
•
Controller deadband.
•
Valve action on LVDT error.
•
Block output display units.
•
Calibration differential voltage values.
•
Demodulator and proportional gain values.
•
Hard manual mode enable.
•
Calibrate/operate mode select.
•
Calibrate go/hold status.
•
Calibration stroke time.
•
Number of calibration cycles.
•
Null check request.
The HSS module sends the following information and status to
the MFP module by way of the I/O expander bus interface:
•
D/A demand value.
•
Servo or I/H output percent.
•
At null indicator.
•
Calculated demodulator and proportional gain inputs.
•
Actuator position.
•
Actuator at LVDT null.
•
New calibration data.
•
Module mode equals normal/hard manual.
•
Calibration status.
•
Good/bad status for:
Positioning.
Analog-to-digital (A/D) and D/A converter.
LVDT primaries.
LVDT secondaries.
Output one.
Output two.
•
Microprocessor/hardware.
•
Communications.
•
Contingency.
Status and Data Buffers
The status and data buffers hold status information and pro-
cess data traveling between the microprocessor and the I/O
expander bus. This allows the two asynchronous busses to
operate together and exchange information using handshake
signals.