Peak/Valley Hold Unit (PVHU) User Manual

Part Number: DO-UM0084/14/UE
V2.5
Reference: Peak_Valley Hold Unit (PVHU) User Manual.docx
Date: 11 March 2015
Version: 1.41
Applies to Firmware Version:
Peak/ValleyHoldUnit(PVHU)UserManual
ProductDescription
The Peak/Valley Hold Unit (PVHU) has two outputs which are used to capture
the maximum (peak) and minimum (valley) values of the input signal. The PVHU
captures the maximum and minimum values and holds these values until either
another maximum or minimum value is detected, or the RESET TIME expires.
The Reset Time can be adjusted from 0% to 100% in three ranges 0 to 500 mS,
0 to 5 sec and 0 to 50 sec (the default is 0 to 500 mS). Various adjustments are
made using multi-turn trimpots beneath the front cover. The signal output DECAY
RATE is the rate at which the outputs decay back to their respective maximum or
minimum values, after the Reset Time has expired. The decay rate can be set
using internal links to be 1 sec, 100 mS, <2 mS or latched until cleared by a digital
input (the default is <2 mS).
The PVHU has four way galvanic isolation of 1000 VDC between the Power In,
the input and each output. The outputs are isolated from each other.
A variety of standard signal inputs and outputs can be accommodated:
0-2 V, 0-5 V, 0-10 V, ±10 V, 0-20 mA and 4-20 mA. The outputs can be different
from each other and also different to the input, so the unit can effectively perform
signal conversion and isolation functions as well. Special input and output ranges
can be provided by arrangement.
Applications
Fast pulse stretching so that transient events can be captured by standard
(slower) controllers or PLCs.
Accelerometer peak level capture for machine condition monitoring.
Hydroelectric turbine generator pole
temperature estimation (see applications at the
end of this document).
Monitoring of rotor alignment in rotating
machines using valley detection.
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FunctionalDiagram
TypicalOperation
This diagram shows the typical operation for a repetitive type of signal with intermittent maxima and
minima. The brown sinusoidal curve represents the input, the magenta line the Peak Output and the
green line the Valley Output.
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Above is shown an example of the outputs one can expect for a fairly high frequency input
signal with the reset time and the decay effect illustrated.
OscilloscopePictures
Single sine burst with peak capture example.
Sine cycles with peak capture example.
Single sine burst with valley capture example.
Sine cycles with valley capture example.
PulsePerformance
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Step input followed by 500µS pulse with output below.
Response reacts within 1 mSec and fairly short pulses
can be captured reliably.
Fast pulse input showing pulse stretching effect which
can be used to allow a slower reacting system to use
transient event inputs.
500µS width pulses showing that no pulses are
missed so long as the input pulse width is longer than
500µS.
Close up of scope picture on left of the pulse train
input. The exponential output response is the reaction
of the filtering present in the output circuit.
Catching fast pulse bursts - illustrating how the output
“holds” the captured input pulses and the way the
output decreases after the Reset Time expires.
The Valley Output in response to short negative pulses
with the Reset Time and the Decay effects.
A close up of actual pulse input in a customer
application which is on the limit of reliable detection.
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Very short pulses, some of which are just too fast for
reliable detection. Some pulses are missed.
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Specifications
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One analogue input, two isolated analogue outputs one for Peak (maximum) value and the other
for Valley (minimum) value.
Input and each output can be configured differently if required. For example the input can be 010 V, the Peak output can be 4–20 mA and the Valley output could be ±5 V.
Galvanic isolation between input, power supply and each output > 1000 VDC.
DC supply required – 12 or 24 VDC, -5%, +10% at 100 mA max.
Typical step response time (input to output) - less than 2 mS.
Split rail powered input circuit to accommodate input signals from ±100 V down to ±100 mV or
±100 mA down to ±100 µA.
Standard process signal inputs available, 0-10 V, 0-5 V, 0-2 V, ±10 V, 0-20 mA, 4-20 mA.
Input impedance standard for voltage inputs at 100 kΩ but can be arranged to be 1 MΩ if
required. Input impedance is 50 Ω for mA current inputs.
DC coupled input signal as standard but can be arranged to be AC coupled if required.
Analogue input resolution 0.3% of input range.
Input sampling frequency approximately 5 KHz (200 µS).
Minimum input pulse width for reliable detection – 1 mS.
Input trimpot zero and span adjustments beneath front panel.
Split rail powered output circuit - output signals from ±12 V down to ±100 mV.
Output current for voltage output option at 5 mA Output current range for current output option
from 0 to 22 mA.
Analogue output resolution 0.05% of range.
Overall accuracy better than 1% of range.
Output trimpot zero and span adjustments for each output beneath front panel.
Reset time adjustable using trimpot beneath front panel from 0 to 100% of the selected range.
Reset time ranges solder links selectable underneath printed circuit board, 0-500 mS, 0-5 Sec,
0-50 Sec and 0-500 Sec, default at 0 - 500 mS.
Decay time selectable using internal PCB links 1 Sec, 100 mS, <2 mS or latched until Digital Input clears.
This time is for output to decay from full scale output to zero.
Default at <2 mS.
Operating temperature -10°C to +70°C.
Power on green LED.
Plug-in screw terminals which can accommodate wire up to
2.0 mm2.
DIN rail mounting enclosure - 22.5 x 100 x 113 mm (width x
length top to bottom x height off DIN rail).
Approximate weight 100 g.
CE compliant.
RemovingtheFrontPaneltoMakeAdjustments
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0
Carefully prise open the enclosure a little
to release the front panel.
Lift and remove the clear front cover.
There are some instructions and
information behind the front panel.
Remove the front panel.
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OpeningtheUnit
Remove the rear rail clamp spring.
Using a screw driver carefully prise
open the rear of the enclosure.
Remove the rear rail clamp.
Carefully prise open the front of the
enclosure.
Access to the Reset Time solder
links is on the underside of the
PCB. Open to get access to the PCB.
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HowtoChangetheResetTimeRange
Open the device and locate the solder links underneath the PCB (default is 0 to 500 mS).
Solder Links
LEDs (if fitted)
Reset Time Range
J1/5
J1/6
A1
A2
0 to 500 mS
OUT
OUT
OFF
OFF
0 to 5 Sec
OUT
IN
OFF
ON
0 to 50 Sec
IN
OUT
ON
OFF
0 to 500 Sec
(8.5 minutes)
IN
IN
ON
ON
DecayTimeSelection
Open the device and locate the solder links underneath the PCB (default at <2 mS).
Solder Links
Decay Time
(time is for output
to decay from full
scale output to zero)
J1/7
J1/8
Decay Rate
(Volts/Sec)
1 Sec
OUT
OUT
10
100 mS
OUT
IN
100
<2 mS
IN
OUT
1000
latched
until Digital Input
clears
IN
IN
Within 10mS
from Digital
Input to clear
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ConfiguringtheInputandOutputs
There are some simple configuration changes that the user can make. These are grouped as:
Changing one or both of
the outputs to be current
or voltage outputs – this is
done simply by changing a
link in the PCB for each
output. It is J2/2 and J3/2
you need to change.
Out #1 (Peak):
J2/2=A → 0-20 mA
J2/2=B → 0-10 V
Out #2 (Valley):
J3/2=A → 0-20 mA
J3/2=B → 0-10 V
Here an example of
changing from 0-2 V Input
to 0-5 V Input:
Changing configuration of
a completed unit is done in
several stages.
Obtain the unit to be changed and locate the relevant documentation, tools, components, etc.
Having opened the unit you will need to change R1/3 from 27K to 100K and re-install R1/4 270K.
Both resistors are in 1206 package.
Now having done this you will need to calibrate the input and outputs.
We can post you updated labels if you change the original configuration.
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For other configuration changes it is best to send it back to us so we can do this for you.
Standard options are:
Inputs: +/-10 V, +/-5 V, +/-2 V, 0-10 V, 0-2 V, 0-5 V, 0-20 mA, 4-20 mA
Outputs: +/-10 V, +/-5 V, +/-2 V, 0-10 V, 0-2 V, 0-5 V, 0-20 mA, 4-20 mA
On request, we can configure the input to be
anything between ±100 V and ±100 mA, down to
±100 mV and ±100 µA. The outputs can be
configured between ±12 V and 0-22 mA and down
to ±1 V and 0-1mA.
ChangingtheAuxiliaryPower
This is not recommended for the user to do. It is best to purchase a device which is made
with the auxiliary supply you require. Options are 12 VDC and 24 VDC. However if you do
need to change this, you need to have some soldering expertise and be able to remove and
replace three DC to DC converters.
CalibratingtheInputandOutputs
In order to achieve the fastest possible response time, all the input and output zero and
span adjustments are done manually by means of offset and gain adjustments using
trimpots.
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This is done in three stages:
1. Set up the input.
2. Set up output 1.
3. Set up output 2.
Locate the 0V and TP1/4 test point to set up
the input stage.
Inject the minimum input value.
Adjust the Zero In trimpot so that the voltage
at TP1/4 is 0.100 V.
Inject the maximum input value.
Adjust the Span In trimpot so that the voltage
at TP1/4 is 4.900 V.
Connect a suitable meter to Output 1.
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Inject the minimum input value.
Adjust the Output 1 Zero so that the output is exactly at the minimum output value.
Inject the maximum input value.
Adjust the Output 1 Span so that the output is exactly at the maximum output value.
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Connect a suitable meter to Output 2.
Inject the minimum input value.
Adjust the Output 2 Zero so that the output is exactly at the minimum output value.
Inject the maximum input value.
Adjust the Output 2 Span so that the output is exactly at the maximum output value.
Repeat low and high adjustments as necessary to get best accuracy.
MountingandConnecting
The PVHU is housed in a vented fire retardant plastic enclosure.
It is easiest to use a screwdriver to lever out the plug-in screw terminal connectors.
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ApplicationExamples
Hydroelectric turbine generator pole temperature estimation We received a request for one of our peak detectors from a customer, whereupon we sent
a unit designed several years back with dual overlapping outputs which did not do the job
required. The application was for detecting the temperature of the poles in a hydroelectric
turbine generator as they passed a fast responding temperature sensor located as close as
possible to the rotor.
The data supplied by the
customer shown below:
“I am attaching a graph of
the signal we are
measuring, effectively a
temperature varying at 120
Hz and of which we wish to
detect the absolute peak.
Effectively, the DC coupling
is crucial; an AC coupled
measurement would not
give us the desired output” –
from the customer.
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Monitoring of rotor alignment in rotating machines –
Providing a simple
alarming system when
the airgap is reduced for
any reason could be a
useful protection feature
for rotating machinery.
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PartNumbering
GB-PH/ab-wxyz/tn
Where:
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ab = input type -
a=
b=
a=
b=
t = operation option
t=
wx = output #1 and yz = output #2-
I: current
A: 4 to 20 mA
B: 0 to 20 mA
D: 0 to 1 mA
E: 0 to 5 mA
V: voltage
A: 0 to 10 V
B: 0 to 50 mV
C: ±50 mV
D: 0 to 5 V
E: ±5 V
F: 1 to 5 V
G: ±10 V
H: 0 to 2 V
w or y =
x/z =
I: current
A: 4 to 20 mA
B: 0 to 20 mA
D: 0 to 1 mA
E: 0 to 5 mA
w or y= V: voltage
x/z = A: 0 to 10 V
D: 0 to 5 V
E: ±5 V
F: 1 to 5 V
G: ±10 V
1: peak hold - alternate output capture
(this operation is described in another User Manual)
2: peak/valley hold
(this is the operation as described in this User Manual)
n = auxiliary supply
n=
C: 24 VDC
D: 12 VDC
Examples:
GB-PH/VE-VEVE/2C Peak/Valley Hold Unit
Input: ±5 V
Output #1: ±5 V
Output #2: ±5 V
Operation: Peak/Valley Hold
Auxiliary Supply: 24 VDC
The User Manual:
Part Number:
Description:
DO-UM0084/12/UE
Peak/Valley Hold Unit (PVHU) User Manual
danntech Ltd
danntech cc
Co. No. 6510211
15 College Close, Hamble-le-Rice
Southampton, Hampshire
SO31 4QU
United Kingdom
Tel: 075 9069 1824
Reg. No. CK1986/15338/23
Tel International: +27 11 7921239
Tel National: 011 7921239
Fax International: +27 11 7924687
Fax National: 011 7924687
e-mail: sales@danntech.com
e-mail: sales@danntech.com
www.danntech.com
P O Box 1023, Fontainebleau, 2032
Republic of South Africa
www.danntech.com
Danntech makes no warranty of any kind with regard to this material, including, but not limited to, the implied warranties of merchantability and fitness for a particular
purpose. Danntech shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing, performance or use
of this material. This document contains proprietary information, which is protected by copyright. No part of this document may be photocopied, reproduced, or
translated into another language without the prior written consent of Danntech. The information in this document is subject to change without notice.
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