Edwards ELD500 Series, Instruction Manual

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D13510840D - Interface description
Page 84
External Calibration
When the leak detector is in measurement mode the command "*CAL" evokes a calibration
routine for external calibration. Before starting the external calibrated leak has to be opened
and the leak rate signal has to be stable. Via the command "*STATus:CAL?" the computer can
detect when the external calibrated leak has to be closed.
When the external calibrated leak is closed and the leak rate signal is stable the computer has
to advise the leak detector via a second command "*CAL". Via the command "*STATus?" the
computer can recognize when the calibration routine has finished.
Fault finding
Common
Error Possible Reason Solution
No characters are
received via the
interface / the
ELD500 does not
answer
Wrong cable Please use a 1:1 cable, (NO null-
modem cable, also called cross-over
cable)
Problems with flow control Deactivate flow control in PC/PLC or
use cable according to the wiring
diagram in Section 2
Wrong COM-Port used at PC Select correct COM-Port
Wrong interface parameters
(Baud rate, Data bits, Parity,
Stop bits)
Check if interface parameters (Baud
rate, number of data bits, parity bit
and number of stop bits in the ELD500
and PC / PLC match)
Wrong protocol selected in
the ELD500
Select correct protocol in the ELD500
PC uses an USB-RS232
converter
In general the ELD500 will also work
with an USB-RS232-converter.
However, these often cause multiple
difficult to track problems (driver, flow
control.) Please test your PC program
on a "real" RS232 interface first
preferably. Especially with USB-RS232-
converters it is often helpful to use a
standard cable.
Serial interface of PC is (still)
occupied with a different
program
Check if other programs (e.g. a
synchronisation software for your
hand-held computer) uses the serial
interface. It is also possible that an
already closed program has not
released the interface again yet. In this
case a restart of the PC will help.