FDY
10
The Interface Solution Experts
PC-Programmable Frequency
Transmitter and Display
Figure 7.
Input Parameters Tab
Programming the Basic Parameters
Programming the Basic Parameters involves selecting
the desired parameters in the PC Program, then
downloading those parameters to the FDY. Begin by
entering the device identifi cation and measurement
mode parameters into the confi guration software.
Device Identifi cation Information
The
Tag
(8 characters, maximum),
Descriptor
(16
characters, maximum) and
Message
(32 characters,
maximum) boxes allow you to assign a unique identity
to each FDY.
Measurement Mode
Select from Frequency, Period, Pulse Width High,
Pulse Width Low and Contact Closure. This selects
the variable to be measured and displayed. (Unless
a custom EGU is selected in the Custom Curve tab.)
(See Figure 5, section 4).
Programming the Input Parameters
When setting input parameters, please read the
following information for guidance. All input voltages
above 3V are internally clamped at 3V and all AC
signals are squared and measured at the zero
crossing. Therefore the settings for input threshold and
hysteresis assume a maximum input of 3V.
Use the Input tab in Figure 7 to enter the following
parameters:
AC / DC Input:
Select the type of input the FDY will
measure.
Input Threshold:
Input threshold is applicable to DC
inputs only. Input Threshold is the input voltage above
which the input is considered high. For input voltages
above 3V, it is recommended to set this to the default
setting of 2V (maximum is 2.5V). For input voltages
below 3V, it is recommended to set this to 2/3 of the
peak-to peak (p-p) input signal voltage plus the low
state signal voltage.
Input Hysteresis:
This is the difference between high
and low voltage points at which the input circuit detects
changes of input state. For DC inputs this must be less
than the threshold. For example, if the threshold is set
for 2V, and the hysteresis is set for 1.2V, the FDY will
detect high for >2V and low for <0.8V.
- For DC input voltages above 3V, it is
recommended to set this to the default setting of
1.2V (maximum is 1.5V).
- For DC input voltages below 3V, it is
recommended to set this to 1/3 of the peak-to peak
(p-p) input signal voltage plus the low state signal
voltage.
- For AC inputs the hysteresis is used to minimise
noise interference. Above 3V, it is recommended to
set this to 150mV.
- For AC inputs below 3V, it is recommended to set
this to 10% of the signal voltage level.
Timeout Period:
The number of seconds that the
input will remain at lower range value before the FDY
declares a hardware error, if the
Fail On Input Timeout
box is checked. The Timeout Period can be confi gured
at minimum of 0.5sec to a maximum of 600sec, factory
default is set to 10sec.
NOTE:
The timeout period must be set greater than the
Lower Range Value period if Fail On Input Time-out is
enabled.
Fail On Input Timeout:
If your input is lower than the
allowed
Lower Range Value
and the
Fail On Input
Timeout
feature is enabled,
Broken Wire
(in the
Device
Status
section of the PC Program) or
Broke Input
(on
the FDY display) is declared after the set Timeout
Period has passed.
