Schmidt SS 20.515 User manual

SCHMIDT®Flow Sensor
SS 20.515
Instructions for Use

Instructions for use SS 20.515 Page 2
SCHMIDT®Flow Sensor
SS 20.515
Table of Contents
1Important information.......................................................................3
2Application range.............................................................................4
3Mounting instructions.......................................................................4
4Electrical connection........................................................................7
5Signaling..........................................................................................9
6Commissioning..............................................................................11
7Information concerning operation..................................................11
8Service information........................................................................12
9Technical data ...............................................................................14
10 EC Declaration of Conformity........................................................15
Imprint:
Copyright 2011 SCHMIDT Technology
All rights reserved
Version: 531227.02A
Subject to modifications

Instructions for use SS 20.515 Page 3
1 Important information
These instructions for use contain all the required information for a fast
commissioning and a safe operation of SCHMIDT®flow sensors:
These instructions for use must be read completely and observed
carefully, before putting the unit into operation.
Any claims under the manufacturer's liability for damage resulting
from non-observance or non-compliance with these instructions will
become void.
Tampering with the device in any way whatsoever - with the excep-
tion of the designated use and the operations described in these in-
structions for use - will forfeit any warranty and exclude any liability.
The unit is designed exclusively for the use described below (refer to
chapter 2). In particular, it is not designed for direct or indirect per-
sonal protection.
SCHMIDT Technology cannot give any warranty as to its suitability
for certain purpose and cannot be held liable for accidental or se-
quential damage in connection with the delivery, performance or use
of this unit.
Symbols used in this manual
The symbols used in this manual are explained in the following section.
Danger warnings and safety instructions - please read and
them!
Non-observance of these instructions may lead to injury of the
personnel or malfunction of the device.
General note
All dimensions are given in mm.
!

Instructions for use SS 20.515 Page 4
2 Application range
The SCHMIDT®Flow sensor SS 20.515 (article number: 524515) is
designed for stationary measurement of the flow velocity and air and gas
temperatures at atmospheric pressure conditions (700 ... 1300 hPa).
The sensor is based on the measuring principle of the thermal anemom-
eter. It measures the mass flow of the measuring medium as flow veloci-
ty, which is output in a linear way as standard velocity
1
wN, based on
standard conditions of 1013.25 hPa and 20 °C. Thus, the resulting out-
put signal is independent of the pressure and temperature of the medium
to be measured.
The sensor is designed for the use inside closed rooms and is not suita-
ble for outdoor use.
3 Mounting instructions
General information on handling
The flow sensor SS 20.515 is a sensitive measuring instrument. This is
why applying mechanical force to the sensor tip should be avoided.
The sensor tip can be damaged irreversibly due to mechanical
loads.
Leave the protective cap as long as possible attached during
mounting and handle the sensor with care.
For applications with an uncontrollable risk of touch, a special safety
strap can be mounted on the sensor (optional accessory: 531026).
Flow characteristics
To avoid false measurement results, appropriate installation conditions
must be guaranteed to ensure that the gas flow is supplied to the sensor
in a quiet (low in turbulence) state.
Correct measurements require a quiet flow low in turbulence.
1
Corresponds to the actual velocity under standard conditions.
!
!

Instructions for use SS 20.515 Page 5
Assembly
For the assembly of the SCHMIDT®Flow sensor SS 20.515, five differ-
ent assembly versions optimized for use in cleanrooms are available, in
order to cover all the different applications (see Table 1).
First, the required holes, depending on the assembly version, must be
drilled, and the corresponding fixing socket must be mounted in that
hole. Then the connecting cable is introduced with its open into the fixing
socket from the cleanroom side until the cable bushing protrudes from
the fixture by only about 5 cm. Please note that after assembling the
sensor, there must still be room for this protruding cable length in the
void behind the assembly bushing. Now connect the sensor to the con-
necting cable (plug in and screw down spigot nut), insert it into the fixture
bushing and tighten the holding fixture screw by hand. Now the sensor
can still be aligned accurately by hand, if required. Finally, the holding
fixture screw must be tightened with a key wrench (wrench size 22) until
the sensor is sufficiently secured against twisting.
Prior to commissioning the sensor, remove the protective cap.
Assembly in the ceiling
The angled sensor is designed for assembly below the ceiling.
After the sensor has been inserted into the fixture bushing and the as-
sembly screw tightened (first only by hand), the sensor head will auto-
matically have an optimum position for the detection of the vertical
downdraft flow from the ceiling. Only the torsional angle of the sensor
arm in parallel to the ceiling must still be aligned. Then tighten the as-
sembly screw using the fork wrench (hold sensor, if necessary) until the
sensor is secured against twisting.
Assembly in the wall
The straight sensor is designed for assembly on a wall.
Insert sensor into the fixture bushing and thoroughly tighten the assem-
bly screw. No alignment to the flow is required, due to the omnidirection-
al measurement characteristic of the sensor head.

Instructions for use SS 20.515 Page 6
Type / Article No.
Drawing
Assembly
Mounting
Type 1
Threaded bush M25 with lock nut:
- For installation in ceilings, walls or
frames with a thickness from 1 to 22 mm.
- Opening with a Ø of 26 mm required for
fixing with lock nut.
- Or insert a thread M25 x 1.5 into ceiling.
Mounting
Type 2
Threaded bush M25 with threaded adapter
M25 x 1.5 for PG:
- For installation in frames with an existing
opening with PG21 thread
(e.g. sprinkler openings in profiles).
Mounting
Type 3
Threaded bush M25 with shank nut:
- For installation in frames with a thickness
from 21 to 40 mm, especially for ceiling
frames made of hollow profiles.
- Openings with a Ø of 26 mm and a Ø of
28.5 mm are necessary.
Mounting
Type 4
Welding bush:
- For welding to stainless steel ceilings or
walls.
Mounting
Type 5
Flanged bushing (pressure-tight till 300 mbar):
- For mounting under the ceiling or at a
wall with two screws M6.
- Opening in ceiling / wall required with a
Ø of 15 mm for cable and 2 threads M6.
Table 1

Instructions for use SS 20.515 Page 7
4 Electrical connection
The sensor is equipped with a plug-in connector which is firmly integrat-
ed into the enclosure. The plug-in connector has the following data:
Number of connection pins: 7 (plus shield connection on the metallic
housing)
Type: male
Locking of connecting cable: M9 spigot nut (on cable)
Type of protection: IP67 (with screwed-down cable type 702)
Model: Binder, series 711
View of plug-in connector of the sensor
The pin assignment of the plug-in connector can be seen from the fol-
lowing Table 2.
Pin
Designa-
tion
Function
Wire color
Connecting cable
1
Power
Supply voltage UB
white
2
Aout Temp
Temperature output
brown
3
internal
-
green
4
internal
-
yellow
5
internal
-
grey
6
Aout Flow
Velocity signal
pink
7
GND
Mass
blue
Shield
Electromechanical shielding
Shield meshwork
Table 2
All signals use GND as electric reference potential.
The cable shield is continuously connected to the metallic housing of the
plug-in connector and the sensor and must be connected to an anti-
interference potential, e.g. ground (depending on the shielding concept).
The housing is connected to GND via a varistor (breakdown voltage
about 30 V).
The wire colour mentioned in Table 2 is applicable when using a
SCHMIDT®cable with material No. 505911-x (x = 1 / 2 / 3).
Make sure that no operating voltage is active during electrical
installation and that the operating voltage cannot be switched
on inadvertently.
!

Instructions for use SS 20.515 Page 8
Supply voltage
For operation in accordance with its designated use, the sensor requires
a DC voltage with a nominal value of 24 V with a permissible tolerance of
± 10 %. The typical operating current is approx. 60 mA and at most
100 mA
2
.
Operate the sensor only within the defined range of operating
voltage (24 V DC ± 10 %).
Undervoltage may result in malfunction, overvoltage may lead
to irreversible damage.
The specifications for the operating voltage are valid for the connection
to the sensor. Voltage drops generated due to line resistances must be
taken into account by the customer.
Analog outputs
The analog outputs of the sensor (flow and temperature) are designed
as high-side drivers, i.e., the apparent ohmic resistance RLmust be con-
nected between the respective signal output and the reference potential
for the sensor outputs (GND, see following figures). The outputs have a
permanent short-circuit protection against both rails of the operating
voltage, while the maximum load capacitance is 10 nF.
There are two output versions (selected by ordering):
- Current interface:
Display range: 4 ... 20 mA
Error signaling
3
: 2 mA
Maximum load resistance RL: 300 Ω
Maximum load capacitance CL: 10 nF
Maximum recommended cable length: 100 m
Wiring:
Figure 4-1
2
Both signal outputs 22 mA (maximum measuring values), minimum operating voltage.
3
Signaling as specified in NAMUR NE 43
!

Instructions for use SS 20.515 Page 9
- Voltage interface:
Display range: 0 ... 10 V
Minimum load resistance RL: 10 kΩ
Maximum load capacitance CL: 10 nF
Maximum short-circuit current: 50 mA
Maximum recommended cable length: 15 m
Wiring:
Figure 4-2
Due to the resistance
4
RWof the connecting cable, the operating current
causes a voltage drop in each wire of the operating voltage, which may
adopt interfering values especially as so-called "mass offset" in the GND
wire.
This is why you have to make sure during installation that the original
lead of the sensor is kept as short as possible. Reconnection to cables
with wider cross-sections near the sensor is recommended.
The voltage drop in the GND wire of the connecting cable
during operation can substantially falsify the analog signal
at the voltage output.
5 Signaling
The sensor SS 20.515 reproduces the respective measuring quantity
linearly on the relevant analog output. The representation specification
depends both on the measuring quantity and the output characteristics
(see figures in the following tables).
Representation of the measuring range
When measuring flow velocity wN,max, the measuring range ranges
from zero flow to the selectable end of the measuring range wN,max (=
100 %, see Table 3).
4
Specific resistance value of standard cable (0.14 mm2): 0.138 /m at = 20° C
!

Instructions for use SS 20.515 Page 10
Voltage mode (U) wN
Current mode (I) wN
U
Out
[V]
0
110
w
N
[%]
10
0
20
11
40
80
60
100
4
2
6
8
Out
N
NU
V
w
w 10max,
)4(
16 max, mAI mA
w
wOut
N
N
Table 3
The measuring range of the temperature of the medium is fixed be-
tween -20 and +70 °C (see Table 4).
Voltage mode (U) TM
Current mode (I) TM
CU
V
TOutM  )20
10
90
(
CmAI
mA
TOutM  ]20)4(
16
90
[
Table 4
Note regarding commissioning:
The temperature output normally provides approx. 5 V or 12 mA be-
cause the typically prevailing room temperature of approx. 25 °C cor-
responds to half the measuring range.
Error signaling
In current mode, the interface outputs 2 mA.
In voltage mode, the output switches to 0 V.
Exceeding the measuring range for the flow
Measuring values larger than wN,max are output in a linear way up to
110 % of the signaling range (11 V or 21.6 mA). At still higher values
of wN, the output signal remains constant.
110 wN [%]
020 40 8060 100
IOut
[mA]
20
4
21,6
12
8
16
UOut
[V]
075 T
M [°C]
10
4
2
20
11
40 7060-20
6
8
075 20 40 7060-20
IOut
[mA]
T
M [°C]
20
4
8
22
1212
16
2
075 20 40 7060-20 0 75 20 40 7060-20

Instructions for use SS 20.515 Page 11
Temperature of the medium outside of specification range
Operation outside the specified limits may damage the sensor and is
displayed as follows (see also graphics in Table 4):
oTemperature of the medium below -20 °C
The analog output for TMswitches to error (0 V or 2 mA).
The analog output for wNswitches to error (0 V or 2 mA).
oTemperature of the medium above +70 °C
Measuring values above TM,max are output in a linear way up to
approx. 75 °C (10.6 V or 21.6 mA).
oTemperature of the medium above +75 °C
5
The analog output for wNsignals an error (0 V or 2 mA).
The analog output TMswitches directly to the maximum output
values of 11 V or 22 mA.
6 Commissioning
Before switching on the SCHMIDT®Flow sensor SS 20.515, it must be
checked if the sensor was installed correctly, both mechanically and
electrically.
If operation takes place according to the designated use, the sensor is
ready for measurement approx. 10 s after switching on the supply volt-
age.
7 Information concerning operation
Ambient condition temperature
The SCHMIDT®Flow sensor SS 20.515 monitors the temperature of
both medium and electronics. As soon as one of the measuring values
leaves the specified operating range, the sensor switches off the flow
measurement and reports the corresponding error. As soon as proper
operational conditions are restored, the sensor resumes the measuring
mode.
Even leaving the specified operating temperature range for a
short period can cause an irreversible sensor damage.
5
The switching hysteresis for the threshold is approx. 2 K.
!

Instructions for use SS 20.515 Page 12
Ambient condition medium
The SCHMIDT®Flow sensor SS 20.515 is designed for use in clean to
slightly contaminated media.
Dirt or other deposits on the sensor cause false measurement
results.
Therefore, the sensor must be checked for contamination at
regular intervals and cleaned if necessary.
The coated version has particularly high chemical media resistance to
organic solvents, acids and bases in liquid or gaseous state, for exam-
ple:
Acetone, ethyl acetate, methyl ethyl ketone, perchloroethylene, peracetic
acid, xylene, alcohols, ammonia, gasoline, motor oil (50 °C), cutting oil
(50 °C), sodium hydroxide, acetic acid, hydrochloric acid, sulfuric acid.
The suitability of the above-mentioned or other similar chemicals must
be checked for every individual case due to different ambient conditions.
(Condensing) liquid on the sensor results in serious measure-
ment errors.
After being dried, the sensor will work again correctly (if the
condensate has not caused any damage, e.g. as a result of cor-
rosion).
Sterilizability
Both uncoated and coated sensors can be sterilized during operation.
Alcohols (drying without leaving residues) and hydrogen peroxide (un-
coated version only) are approved and certified disinfectants.
Other disinfectants must be checked by the customer if necessary.
8 Service information
Maintenance
Heavy contamination of the sensor head may lead to false measured
values. Therefore, the sensor head must be checked for contamination
at regular intervals. If contaminations are visible, the sensor can be
cleaned as described below.
!
!

Instructions for use SS 20.515 Page 13
Cleaning of the sensor head
The sensor head can be cleaned to remove dust or dirt by moving it
carefully in warm water containing a dishwashing liquid or other allowed
cleaning liquid (e.g. isopropanol)
6
. Persistent incrustations or deposits
can be previously softened by prolonged immersion and then removed
by means of a soft brush or cloth. Avoid applying force to the sensitive
sensor tip.
The sensor head is a sensitive measuring system.
During manual cleaning proceed with great care.
Before putting it again into operation, wait until the sensor head is com-
pletely dry.
Transport / Shipment of the sensor
Before transport or shipment of the sensor, the delivered protective cap
must be slid over the sensor head. Avoid contaminations or mechanical
stress. Moreover, every return must be accompanied by a completely
filled-in decontamination declaration (for a form, go to
www.schmidttechnology.de).
Recalibration
If the customer has made no other provisions, we recommend repeating
the calibration at a 12-month interval. To this end, the sensor must be
sent to SCHMIDT Technology.
Spare parts or repair
No spare parts are available, since a repair is only possible at SCHMIDT
Technology. In case of defects, the sensors must be sent in to the sup-
plier for repair.
When the sensor is used in systems important for operation, we recom-
mend you to keep a replacement sensor in stock.
Test certificates and material certificates
Every new sensor is accompanied by a certificate of compliance accord-
ing to EN 10204-2.1. Material certificates are not available.
Upon request, we shall prepare, at a charge, a factory calibration certifi-
cate, traceable to national standards.
6
Other cleaning agents upon request.
!

Instructions for use SS 20.515 Page 14
9 Technical data
Technical data
Measuring quantities
Standard velocity wNof air, based on standard conditions
of 20 °C and 1013.25 hPa
Temperature of the medium TM
Medium to be measured
Air or nitrogen, other gases on request
Measuring range wN
0 ... 1 / 2.5 / 10 m/s
Lower detection limit wN
0.06 m/s
Measuring accuracy wN
- Standard
- Precision7(optional)
±(3 % of measured value + 0.05 m/s)
±(1 % of measured value + 0.04 m/s)
Reproducibility wN
±1.5 % of measured value
Response time (t90) wN
3s (jump from 0 to 5 m/s)
Operating / Measuring
range TM
-20 ... +70 °C
Measuring accuracy TM
(wN> 1 m/s)
±0.4 K (10 ... 30 °C)
±1 K (remaining measuring range)
Humidity range
0 to 95 % of rel. humidity (RH), non-condensing
Operating pressure
Atmospheric (700 ... 1300 hPa)
Supply voltage UB
24 VDC ± 10 %
Current consumption
typ. < 60 mA, 100 mA max.
Analog outputs
- Voltage output
- Current output
Maximum load capacitance
Selectable when ordering
0 ... 10 V for RL≥ 10 kΩ
4 ... 20 mA for RL≤ 300 Ω
10 nF
Electrical connection
Plug (male) M9, 7-pin
Line length
15 m max. (Voltage output)
100 m max. (Current output)
Type of protection
IP 65 (only with correctly connected connecting cable)
Protection class
III (SELV) or PELV8
Mounting
Accessories (see chapter 3)
Material
- Sensor head / tube
- Sensor holder
Stainless steel 1.4571, PBT
Brass, nickel-plated
Installation length L
- Angled:
- Straight:
270 mm x 300 mm
300 mm (standard); special length up to 1000 mm
Weight
300 g max. (straight, 1000 mm, type 3)
Table 5
7
Under calibration conditions and with regard to reproducibility of the reference.
8
According to EN 50178

Instructions for use SS 20.515 Page 15
10 EC Declaration of Conformity

Instructions for use SS 20.515 Page 16
SCHMIDT Technology GmbH
Feldbergstrasse 1
78112 St. Georgen / Schwarzwald
Phone [phone] / 899-0
Fax [phone] / 899-101
[e-mail]
www.schmidttechnology.de