National Instruments FIELDPOINT cFP-PWM-520 User manual

FIELDPOINT™OPERATING INSTRUCTIONS
AND SPECIFICATIONS
FP-PWM-520 and
cFP-PWM-520
Eight-Channel, 5 V or 10–30 V PWM Output Module
These operating instructions describe how to install and use
the National Instruments FP-PWM-520 and cFP-PWM-520
pulse-width modulation modules (referred to inclusively as the
[c]FP-PWM-520). For details on configuring and accessing the
[c]FP-PWM-520 over a network, refer to the user manual for the
FieldPoint network module you are using.
Features
The [c]FP-PWM-520 is a FieldPoint pulse-width modulation
(PWM) output module with the following features:
• Eight PWM sourcing output channels
• 0 to 100% duty-cycle capability with 12-bit resolution
• Short-circuit protection for outputs
• Outputs source 5 VDC or 10–30 VDC with user-provided
power supply
• Independent configuration of the output period for each
channel from 1 to 65,535 ms in 1 ms increments
• On/Off LED indicators
• 250 Vrms CAT II continuous channel-to-ground isolation,
verified by 2,300 Vrms, 5 s dielectric withstand test
• –40 to 70 °C operation
• Hot swappable

FP-PWM-520 and cFP-PWM-520 2 ni.com
Installing the FP-PWM-520
The FP-PWM-520 mounts on a FieldPoint terminal base
(FP-TB-x), which provides operating power to the module.
Installing the FP-PWM-520 onto a powered terminal base does
not disrupt the operation of the bank.
To install the FP-PWM-520, refer to Figure 1 and complete the
following steps:
1. Slide the terminal base key to either position X, used for any
module, or position 4, used for the FP-PWM-520 module.
2. Align the FP-PWM-520 alignment slots with the guide rails on
the terminal base.
3. Press firmly to seat the FP-PWM-520 on the terminal base.
When the module is firmly seated, the terminal base latch locks
it into place.
Figure 1. Installing the FP-PWM-520
1 I/O Module
2 Terminal Base
3 Alignment Slot
4 Terminal Base Key
5 Latch
6 Guide Rails
1
3
2
4
5
6

© National Instruments Corp. 3 FP-PWM-520 and cFP-PWM-520
Installing the cFP-PWM-520
The cFP-PWM-520 mounts on a Compact FieldPoint backplane
(cFP-BP-xor cFP-180x), which provides operating power to the
module. Installing the cFP-PWM-520 onto a powered backplane
does not disrupt the operation of the bank.
To install the cFP-PWM-520, refer to Figure 2 and complete the
following steps:
1. Align the captive screws on the cFP-PWM-520 with the screw
holes on the backplane. The alignment keys on the
cFP-PWM-520 prevent backward insertion.
2. Press firmly to seat the cFP-PWM-520 on the backplane.
3. Using a number 2 Phillips screwdriver with a shank of at least
64 mm (2.5 in.) length, tighten the captive screws to 1.1 N ⋅m
(10 lb ⋅in.) of torque. The nylon coating on the screws prevents
them from loosening.
Figure 2. Installing the cFP-PWM-520
1 cFP I/O Module
2 Captive Screws
3 cFP Controller Module
4 Screw Holes
5 cFP Backplane
2
2
1
35
4
4

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Wiring the [c]FP-PWM-520
The FP-TB-xterminal base has connections for each of the eight
output channels and for an external power supply to power the
output channels and field devices. The cFP-CB-xconnector block
provides the same connections. Each channel has one output
terminal (VOUT), one supply terminal (VSUP), and two common
terminals (COM). All eight channels are referenced to the COM
terminals. The V and VSUP terminals are all internally connected,
as are the C and COM terminals.
Table 1 lists the terminal assignments for the signals of each
channel. Terminal assignments are also listed on the side panel
of the cFP-PWM-520 and under the slide-in card on the front of the
FP-PWM-520. Connect to the terminals using the terminal base,
connector block, or other connectivity accessory.
Use a 5 VDC or 10–30 VDC external power supply for the output
channels. The power supply must provide enough current to power
all of the loads on the output channels, up to a maximum of 1 A per
channel. Connect the external power supply to multiple V and VSUP
terminals and to multiple C and COM terminals as needed to
ensure that the maximum current through any terminal is 2 A
or less.
Table 1. Terminal Assignments
Channel
Terminal Numbers
VOUT*VSUP†COM
0 1 17 2, 18
1 3 19 4, 20
2 5 21 6, 22
3 7 23 8, 24
4 9 25 10, 26
511 27 12, 28
613 29 14, 30
715 31 16, 32
*Install a 1 A maximum, fast-acting fuse on each VOUT terminal.
†Install a 2 A maximum, fast-acting fuse on each VSUP terminal.

© National Instruments Corp. 5 FP-PWM-520 and cFP-PWM-520
Install a 2 A maximum, fast-acting fuse between the external
power supply and the VSUP terminal on each channel. Install
a 1 A maximum, fast-acting fuse suitable for the load at the
VOUT terminal. Figure 3 shows fuses where appropriate.
Figure 3. Wiring the [c]FP-PWM-520
Caution Maximum output current for the cFP-PWM-520
is lower than 1 A if the module is operating in the
50–70 °C temperature range. Refer to the Specifications
section for more information, and select fuses for the VOUT
terminals accordingly.
Pulse-Width Modulator Output Circuit
The [c]FP-PWM-520 output channels are optically isolated from
the rest of the FieldPoint bank. The channels are sourcing outputs
with short-circuit protection circuitry. Sourcing current means that
the VOUT terminal provides a path to a voltage supply. In the ON
state of the output period, a transistor is turned on between VSUP
and VOUT. In the OFF state, this transistor is turned off, allowing
only a small leakage current to flow.
C V
V
SUP
V
OUT
[c]FP-PWM-520
COM
Protected
Sourcing
Output
+
–
Load
5 VDC or
10–30 VDC
External
Power Supply
COM
2
A
M
ax
User-Supplied
Fuse
1 A Max
User-Supplied
Fuse

FP-PWM-520 and cFP-PWM-520 6 ni.com
In the ON state, the effective resistance between VOUT and VSUP
causes a voltage drop between the external supply voltage and the
output voltage. For example, if the external supply voltage is 5 V
and the output current is 1 A, calculate the output voltage as
follows:
5 V – (1 A ×RON) = VOUT
where RON is the ON resistance and VOUT is the output voltage.
Refer to the Specifications section for the value of the ON
resistance.
Short-Circuit Protection
If the protection circuitry detects a short-circuit condition on an
output channel, it disables the output. If the protection circuitry
disables an output that would otherwise be in the ON state, the
status indicator for that channel is still lit, but the output transistor
is turned off.
Detecting a Short-Circuit Condition
To determine whether a channel is in a short-circuit condition,
complete the following steps:
1. In FieldPoint software, set the duty cycle to 100% for the
channel in question. Refer to the Configuring the Output
Channels section for more information about configuring the
duty cycle.
2. Measure the voltage between the VOUT and VSUP terminals for
that channel.
Under normal load conditions, the VOUT-to-VSUP voltage is
less than 1 V when the output is ON continuously. Any voltage
higher than 1 V indicates a short circuit. Typically, the
VOUT-to-COM voltage is almost zero if the protection circuitry
is activated.
Resetting a Channel in a Short-Circuit Condition
To reset a channel in a short-circuit condition, determine the cause
of the condition and disconnect the load from the channel. The
channel resets automatically when the load is removed.
Alternatively, if completely removing the channel load is not
convenient, reset the channel in any of the following ways:
• In FieldPoint software, set the duty cycle to 0%. The channel
resets immediately.

© National Instruments Corp. 7 FP-PWM-520 and cFP-PWM-520
• Disconnect the external power supply from the
[c]FP-PWM-520.
• Remove the [c]FP-PWM-520 from the terminal base or
backplane.
• Power off the network module connected to the
[c]FP-PWM-520.
Normal operation can resume after you correct the short-circuit
condition.
Overcurrent Protection
Each output channel on the [c]FP-PWM-520 has circuitry that
protects it from current surges resulting from short circuits.
Whether the module suffers damage from overcurrent conditions
depends on the following factors:
• The amount of current through the channel
• The amount of time the current is above the current limit
• The frequency of current surges
If the level of current through the output terminal is higher than the
guaranteed trip current for the module, the channel trips and goes
into an overcurrent state. In an overcurrent state, the channel turns
off and the module is not damaged. If the level of current through
the output terminal is higher than the minimum possible trip
current and lower than the guaranteed trip current, the state of the
channel is indeterminate and depends on factors such as the current
level, the temperature, and the power supply.
Inrush currents that exist for less than the trip time do not trip the
protection circuitry. Refer to the Specifications section for more
information about the maximum continuous output current, trip
current, and trip time.
Power Supplies and Overcurrent Conditions
If a short circuit occurs, the current through an output terminal can
exceed the current rating for the power supply and the maximum
continuous current for the [c]FP-PWM-520.
If the power supply you are using with the [c]FP-PWM-520 cannot
supply more than the guaranteed trip current, the module may be
damaged if a short circuit occurs.

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Configuring the Output Channels
A [c]FP-PWM-520 output channel uses period and duty-cycle
settings to determine when the channel is on or off. To configure
the period, complete the following steps in Measurement &
Automation Explorer (MAX):
1. On the Channel Configuration tab for the [c]FP-PWM-520,
select Period from the Attribute menu.
2. Enter an integer between 1 ms (1 kHz) and 65,535 ms
(0.01525 Hz) in the Value field.
To configure the duty cycle, write to the channel for which you
want to set the duty cycle. The duty cycle is the proportion of time
that the PWM signal is ON over the period.
Enter a value from 0 to 100 to set the duty cycle. The duty cycle has
12-bit resolution (4,096 discrete duty-cycle settings).
Figure 4. Period and Duty Cycle of a PWM Output
Status Indicators
The [c]FP-PWM-520 has two green status LEDs, POWER and
READY. After you insert the FP-PWM-520 onto a terminal base
or the cFP-PWM-520 onto a backplane and apply power to the
connected network module, the green POWER indicator lights
and the [c]FP-PWM-520 informs the network module of its
presence. When the network module recognizes the
1 PWM Output 2OnTime 3Period
Duty Cycle OnTime
Period
---------------------100×=
0
VSUP
1
3
2 2
3

© National Instruments Corp. 9 FP-PWM-520 and cFP-PWM-520
[c]FP-PWM-520, it sends initial configuration information to the
[c]FP-PWM-520. After the [c]FP-PWM-520 receives this initial
information, the green READY indicator lights and the module is
in normal operating mode.
In addition to the green POWER and READY indicators, each
channel has a numbered, green status LED that lights when the
channel is in the ON state.
Upgrading Your FieldPoint Firmware
You may need to upgrade your FieldPoint firmware when you add
new I/O modules to your FieldPoint system. For information on
determining which firmware you need and how to upgrade your
firmware, go to ni.com/info and enter fpmatrix.
Isolation and Safety Guidelines
Caution Read the following information before
attempting to connect the [c]FP-PWM-520 to any circuits
that may contain hazardous voltages.
This section describes the isolation of the [c]FP-PWM-520 and its
compliance with international safety standards. The field wiring
connections are isolated from the backplane and the inter-module
communication bus. The isolation barriers in the module provide
250 Vrms Measurement Category II continuous isolation, verified
by 2,300 Vrms, 5 s dielectric withstand test. The [c]FP-PWM-520
provides double insulation (compliant with IEC 61010-1) for
working voltages of 250 Vrms1. Safety standards (such as those
published by UL and IEC) require the use of double insulation
between hazardous voltages and any human-accessible parts or
circuits.
Never try to use any isolation product between human-accessible
parts (such as DIN rails or monitoring stations) and circuits that
can be at hazardous potentials under normal conditions, unless the
product is specifically designed for such an application, as is the
[c]FP-PWM-520.
1 Working voltage is defined as the signal voltage plus the common-mode voltage.
Common-mode voltage is the voltage of the module with respect to ground.

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Even though the [c]FP-PWM-520 is designed to handle
applications with hazardous potentials, follow these guidelines to
ensure a safe total system:
• There is no isolation between channels on the
[c]FP-PWM-520. If a hazardous voltage is present on any
channel, all channels are considered hazardous. Make sure that
all other devices and circuits connected to the module are
properly insulated from human contact.
•Donot share the external supply voltages (the V and C
terminals) with other devices (including other FieldPoint
devices), unless those devices are isolated from human contact.
• For Compact FieldPoint, you must connect the protective earth
(PE) ground terminal on the cFP-BP-xbackplane to the system
safety ground. The backplane PE ground terminal has the
following symbol stamped beside it: . Connect the
backplane PE ground terminal to the system safety ground
using 14 AWG (1.6 mm) wire with a ring lug. Use the 5/16 in.
panhead screw shipped with the backplane to secure the ring
lug to the backplane PE ground terminal.
• As with any hazardous voltage wiring, make sure that all
wiring and connections meet applicable electrical codes and
commonsense practices. Mount terminal bases and backplanes
in an area, position, or cabinet that prevents accidental or
unauthorized access to wiring that carries hazardous voltages.
•Donot use the [c]FP-PWM-520 as the only isolating barrier
between human contact and working voltages higher than
250 Vrms .
• Operate the [c]FP-PWM-520 only at or below Pollution
Degree 2. Pollution Degree 2 means that only nonconductive
pollution occurs in most cases. Occasionally, however, a
temporary conductivity caused by condensation must be
expected.
• Operate the [c]FP-PWM-520 at or below Measurement
Category II. Measurement Category II is for measurements
performed on circuits directly connected to the low-voltage
installation. This category refers to local-level distribution,
such as that provided by a standard wall outlet.