MKS T3PIA, Instruction Manual, Page: 44 / 70

Chapter Four: Analog/TTL Operation Setting the Analog Set Point Inputs
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Setting the Analog Set Point Inputs
The analog set point inputs, (+) set point and (-) set point (pins 9 and 10 respectively on the Interface
connector) are fully differential. The (-) set point must be connected to a ground to work correctly, and it is
recommended that it be connected to ground at the source of the set point signal. If suitable ground is not
available at source of set point, connect pin 10 to pin 13.
Selecting the Digital Output Functions
Table 19: Digital Output Functions
I/O Pin No. State Digital Output Function
20 Low
High
Valve is open
Valve is not open
21 Low
High
Valve is closed
Valve is not closed
Using RS-232 Commands with an Analog T3P
RS-232 settings are:
„
baud rate for an Analog T3P is 19,200
„
8 data bits
„
None parity
„
1 stop bit
The RS-232 should be used for configuration or to read parameters, but not to directly control the valve.
If the T3P is to be operated via RS-232, the device must be reconfigured from Analog mode to Serial mode.
Please consult MKS Applications for assistance.
How Analog Inputs and RS-232 Commands Interact
Consider this example:
The valve is being held closed via a TTL Valve Close signal and the valve is closed.
An RS-232 serial command is sent to Open the valve.
The RS-232 signal is processed, and the valve is instructed to open.
Approximately 50 msec later, the TTL Valve Close signal is read again and the valve is instructed to
move closed.
Refer to the MKS Type T3BIA/T3PIA Valves with RS-232 Interface Supplement for the complete list and
description of serial commands.