3
Fig. 4.1. Typical Alarm Circuit.
1” Fig, 4.1 the 10-V Analog output of th,e 449 is suggested
as the 467 Input signal. For this com,bmatlon the front-
panel switch of the 461 must be set et High. AS an alternate,
the461 Inputcould be furnished from a 100.mV source and
rhe front.p.mel switch set at Low, and the system would
operate in the same nl~!ner.
The circuit of Fig. 4.1 does not require the use of Disc B.
To prevent a false alarm that would result from triggering
of the Disc B portion of the 461, the Internal switch to
control the relay must be set at A Only. As a suggestion,
the Disc B control could be adjusted for a IOWX level than
Disc B with the internal switch for Disc B set et High, and
the Disc B front-panel light will then Serve as a monitor of
some intermediate rate.
Figure 4.2 shows an application of the 461 as a process
controller, For an example, suppose that the internal switch
for Disc B were set at Low. The Controller #l circuit
would then indicate when an input rate fell below some
minimum level and Controller #2 would indicate when the
input rate increases above ?ame maximum level. By using
the Disc A and Disc 6 controls to identify these maximum
Fig. 4.2. Typical Process Control Circuit,
and minimum rates, the operation of an automated
production line could be kept within a controlled range.
The rates could represent the number of pieces in an
assembly line, the average weight at a point on a moving
belt, the moisture content in a slurrv mixture, or any other
variable quantity in an automated process. In addition to
the suggested signals from the BNC connectors, the flexible
relay circuits are also available for any powered functions
that can be controlled automatically.
Although the461 was designed as an accessory to a standard
NIM ratemeter, and these typical applications have been for
e ratemeter as a source for the input, any analog signal
source could be used. The only restrictions on the analog
inputare that it must fall within either the @ to +10-V High
input range or the O- to +lOO-mV Low input range in
order for the responses of the 461 discriminators to be
adjusted for sensitivity to changes in the input analog levels.
The dc output of a preamplifier can be used to indicate
en input rate directly. A voltage can be obtained that is
proportional to accelerator beam current, and adjusted
for compatability with the 461. Voltage monitoring for the
appropriate dc range can be arranged easily for many
various applications.
5. CIRCUIT DESCRIPTION
5.1 GENERAL
The circuits of the OR‘TEC 461 Alarm Control are shown
in schematic 461.0101.Sl at the back of this manual. The
mPut circuits are et the left on the diagram, Discriminator
A is across the top, and Discriminator B is across the lower
Portion of the schematic,
5.2 INPUT CIRCUIT
An analog input can be connected into the 461 through
either the front- or rear-panel BNC connector. Since these
Connectors are not isolated, input signals should not be
furnished into both connectors simultaneously. If the
front-panel switch is set at High, the input will be
furnished directly to both the Disc A and Disc B circuits.
lf the Switch is set at Low, the input is routed through an
amplifier, IC 1, and then is furnished to the discriminators.
P*tmiometer R13 balances the dc level of the IC 1
amplifier. The actual range of voltages applied to the
discriminators is o to 6 v.
5.3 DISCRIMINATOR A
IC 2 is Discriminator A. A bias level is furnished to pin 3
from the Disc A control, and the input level is furnished to
pin 2. As long as the level et pin 3 is more positive than the
level at pin 2, Disc A is not triggered. When the level at pin
2 increases above the bias at pin 3, the discriminator is
triggered on and will remain in this state until the input
level drops below the bias level again.
While IC 2 is not triggered, Ql conducts and holds the
Q2 emitter negative. This cuts off 03. Q6. and 04. With
Q3 cut off, the front-panel lamp will not light. With Q6
cut off, there is no signal to the relay. With 04 cut off, the
signal through the rear-panel Disc A BNC is held et 0 V.
When IC 2 is triggered, it cuts off Ql and makes the Q2
emitter more positive. This turns on Q3 and the front-panel
Disc A lamp; Q6 conducts and de-energizes the relay; and
Q4 conducts and furnishes a nominal +5 V through the
Disc A rear-panel BNC connector.
