MKS P9B, Instruction Manual, Page: 46 / 112

Chapter Four: Analog and Digital Interface Analog Interface Input and Output Options
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5. In selecting the appropriate type and wire size for cables, consider:

Voltage ratings.

Cumulative I
2
R heating of all the conductors (keep them safely cool).

IR drop of the conductors, so that adequate power or signal voltage gets to the device.

Capacitance and inductance of cables that handle fast signals (such as data lines or stepper motor
drive cables).

Some cables may need internal shielding from specific wires to others.
Analog Interface Input and Output Options
The P9B analog I/O MFC is available with either a 9 pin D male connector or a 15 pin D male
connector for providing power and signal I/O.
Table 8: Analog Interface – 9 Pin D Males Pinouts – Model Code A
Pin 1 Valve Open/Close: Apply +5 to+15 VDC to Open; Pull to ground or apply -5
to -15 VDC to Close.
Pin 2 Flow Output Signal, 0-5 VDC
Pin 3 +15 to +24 VDC Power Supply (+/-5% about nominal supply)
Pin 4 Power Common (See Note 2 below)
Pin 5 No Connection
Pin 6 Setpoint Input, 0-5 VDC
Pin 7 Signal Common
Pin 8 Signal Common
Pin 9 Valve Test Point
Notes
1. Chassis ground is not available on a separate pin. Instead, it is carried out through the cable
shielding. Be sure that the connector on the other end of the cable is properly grounded to its
chassis ground.
2. Signal common and power common are not connected within the device. The user must
connect the power common to the signal common at either the “tool-side” (recommended) or at
the MFC, but not at both locations. Connecting at both locations will cause ground loops.
3. The 0 to 5 VDC flow signal output comes from pin 2 and is referenced to pin 7 (signal
common).
4. Use any appropriate 0 to 5 VDC input signal of less than 1K ohm source impedance
referenced to pin 7 as the setpoint signal to pin 6.