22
300544660_002_C1
11/2016
- © Leybold
Digital output
Q:
How fast can I request pressure measurements via the digital interface?
A: 5
0 times per second is the pressure report frequency.
Q:
How long is the waiting time from turning power on to valid measuring values?
A:
The power on sequence is approximately 2 seconds. The digital interface will not reply to commands sent
during this period.
Q:
The first character is sometimes lost in the transmitter digital communication reply?
A:
This can be caused by too fast transmitter communication reply. See RS delay command description in the
RS232 Instruction Manual part 300544665.
Q:
Is it necessary to use the ground wire between RS232 communication equipment and transmitter?
A:
Yes. RS232 communication requires a 3 wire connection between transmitter and communication equipment.
Calibration and adjustment
Q:
How often does the transmitter require calibration or zero adjustment?
A:
Leybold
recommends that the transmitter’s calibration be checked against a known pressure reference
approximately every 12 months. Zeroing frequency is highly dependent on the application, and users must
determine this empirically. Generally, frequent exposure to atmospheric pressure and to corrosive or condensable
gases will require more frequent zeroing.
Q:
The system’s vacuum pumps
cannot
achieve a base pressure below the transmitter’s resolution. How should
the zero adjustment be used?
A:
When the vacuum pumps cannot reach a base pressure within
the transmitter’s resolution, the user must note
the actual base pressure achieved prior to zeroing the transmitter. Then follow either of the two methods given
below:
Perform zeroing of the transmitter via the pushbutton, and then use the ramp function method described
under
Zero Adjustment with RAMP Function
in Chapter 5 Section 5.2 to reach the base pressure.
Perform zeroing of the transmitter via the pushbutton and then subtract the actual base pressure from all
subsequent readings from the transmitter.
Q:
How long is the warm-up time before obtaining reliable measurements from the transmitter?
A:
The transmitter output is available within a few seconds of startup, but its published accuracy and performance
specifications may not be met until it has been operating for 15 to 20 minutes.
Q:
Will the transmitter retain user calibration after power is shut off?
A:
Yes. All transmitter parameters are stored internally in the transmitter
’s
non-volatile memory.
Service and repair
Q:
+24 VDC supply voltage has been connected to analog . Is the transmitter damaged?
A:
Probably yes. The analog output is not protected against applying power to the output pin.
Q:
Reverse voltage has been connected to power supply input. Is the transmitter damaged?
A:
Not likely. The transmitter power supply circuit has reverse voltage and over voltage protection however,
Leybold cannot guarantee that the transmitter will not be damaged.
Q:
Someone dropped the transmitter on the floor. Will it still operate correctly on our system?
A:
Not likely. The transmitter is a precision electromechanical measurement sensor, and the impact with the floor
probably damaged its sensor permanently.
