Analog Output; Relays - Omega CYD211 User Manual

2.6

ANALOG OUTPUT

The Analog Output available on the rear panel of the Model CYD211 can
be configured as either a voltage or current output that can be used for
monitor and control applications. Its most basic function is a temperature
monitor where it puts out a voltage or current that is proportional to
temperature. Refer to Paragraph 3.8 to configure the analog output.
In voltage mode the analog output can vary from 0 – 10 V with a resolution
of 0.15 mV or 0.0015% of full scale. The output can drive a resistive load
of no less than 500 Ω. The output is short-circuit protected so the instrument
is not harmed if the load resistance is too small. However, this practice is
not recommended as the additional load on the instrument power supply
causes noise on internal circuits.
In current mode, the analog output can vary from 4 to 20 mA with a
resolution of 0.3 µA or 0.0015% of full scale. The output is limited by a
10 V compliance voltage so the largest resistive load that the output can
drive in current mode is 500 Ω.
The output for the analog output is available from Pins 6 and 18 of the
Input/Output connector. See Figure 2-3. The terminal marked analog output
signal is the output voltage terminal, the terminal marked analog output
ground is the ground and is attached to chassis ground inside the instrument.
It is not recommended to attach the analog output ground to a ground
outside the instrument. The output should be read by an instrument with an
isolated or differential input wherever possible. Connecting to an external
ground can cause noise in the analog output voltage or the sensor input
measurement. If this cannot be avoided, try to keep the chassis of the two
instruments at the same potential with a ground strap.
2.7

RELAYS

The Model CYD211 has two relays, labeled high and low. The relays are
most commonly associated with the alarm feature. The relays can also be
placed in manual mode and controlled directly by the user from the front
panel or over the computer interface. Refer to Paragraph 3.7 and the
RELAY command in Chapter 4.
Normally Open (N.O.), Normally Closed (N.C.), and Common (COM)
contacts are available for each relay. All contacts (including common) are
isolated from the measurement and chassis grounds of the instrument. If a
relay is inactive (Off), it will be in its normal state of open or closed. When
the relay is active (On), it will be in the opposite state. Relay connections
are available on the Input/Output connector. See Figure 2-3.
2-8
Omega Model CYD211 User's Manual
Installation