Bray 52 Series - Manual (Page 7)

5
BRAY Series 52 Valve Status Monitor
Operation and Maintenance Manual
Introduction
Note: The following information is intended to as-
sist individuals with the use and support of the
Bray S52 Valve Status Monitors.
The Series 52 Valve Status Monitor has been de-
signed to provide valve position indication. The
2N1TM ProxSensor is available in several con-
figurations:
• DC Version 10-30VDC PNP (Sourcing)
• DC Version 10-30VDC NPN (Sinking)
• DC NAMUR Intrinsically Safe Version
(to be used with IS Barrier)
• AC Version 20-250VAC, 50-60Hz
• Fieldbus capable Versions
1. AS-i (Actuator Sensor Interface)
2. DeviceNet
3. PROFIBUS DP (Process Fieldbus
Decentralized Peripherals)
Each of these configurations will be covered in
more detail on the pages that follow. Additional-
ly, examples of how to apply some of these prod-
ucts will be given.
All Bray S52 Valve Status Monitors utilize solid
state switches. Although the solid state switch
performs the same function as a conventional me-
chanical switch, there are differences in the way
solid state switches operate.
NOTICE
It is very important for the user to pay close
attention to the exact specifications of their
sensor in order to avoid damaging the unit.
Solid state switches have current restrictions im-
posed by the semi conducting materials used to
form the sensor. These current limitations have to
be accounted for during setup. Unlike mechani-
cal switches, which can normally handle several
amperes of current flowing through them, solid
state switches are generally rated for half an am-
pere or less.
NOTICE
The Parameters of the S52 must be
compatible with the application
When working with the S52, several parameters
must be considered. A few of which (with signifi-
cant importance) are listed here: operating volt-
age, maximum switching current, output voltage
drop, and residual current. Using an S52 outside
of these parameter limits can cause damage to the
unit and void factory warranty.
Operating voltage is the amount of voltage nec-
essary for the sensor to operate. The maximum
switching current is the largest amount of cur-
rent that the sensor’s solid state electronics can
have flowing through them in the On-State (when
the target is in proximity of the sensor). During
commissioning, it is up to the user to correctly ap-
ply the sensor to their control system in order to
limit the current flowing through the device. This
is done through the use of a load; all the wiring
diagrams associated with the S52s specify where
this load needs to be placed in the circuit. Com-
mon control systems utilize a digital input card
to monitor devices like the S52; these cards have
loads (parameter usually referred to as “input im-
pedance”) – it is the responsibility of the user to
ensure that this load is sufficiently sized to limit
the current flowing through the S52 below the
maximum switching current, yet above the On-
State input current minimum of their monitoring
device. We will cover an example of this on page
14-15.
Output voltage drop is defined as the amount of
voltage that will drop across the solid state switch.
This voltage drop will often vary with the amount
of current flowing through the sensor and the load.