Table of Contents
Advertisement
This controller operates one point at a time; its
capacity is 128 points. The command word specifies
which point is to be selected, an "up or down" bit
for set point changes, and the pulse count (up to 255).
The pulses come from the power line or from an
optional oscillator operating at any pre-selected,
fixed, frequency in the range 20-20, 000 Hz.
Like the AIS and MOC, this controller will de-
tect, alarm and prevent an attempt to operate an
improper number of points simultaneously.
Varie1ble Output Controller (VOC)
This controller is designed for direct digital
control (DDC) service.
It
provides either
incre'
-
mental or absolute position analog outputs from a
single, shared, solid-state digital-to-analog con-
verter. The controller's capacity is 64, 128, 256
or 512 outputs.
Tc/JC command word
(A)
16
8 bits
Quantity of timing pulses
Drive
Relay
10
Driven by a TOM function, the VOC receives a
control word containing a 9-bit address, one bit
to indicate incremental or absolute position output,
and 12 bits of output value.
If
the output is absolute,
the 12 bits represent its magnitude; if incremental,
sign plus 11 bits.
The VOC delivers up to 50 ma. d-c to a maxi-
mum burden of 300 ohms and can drive a set point
up to
10%
of full scale with one operation. Since
each operation takes five ms, the maximum output
rate is 200 per second.
Mercury-wetted-contact relays are used for
output multiplexing, for maximum safety and
isolation. Like the other
GE/
PAC 4020 computer
process control output subsystems, the
voe
is pro-
tected against multiple outputs.
If
de sired, two
voe'
s can be connected in a
backup manner to the same GE
/
PAC 4020 computer.
9
8
7 6
matrix address
[o
= pulsed output
' - - - - - - \..1 = timed output
.__ __ [o
=move setpoint down
ll
= move setpoint up
Decode
One of 128 Points
I I
Pulse or
4
4m--------1
1--------11••
level output
Timed Output Controller
35
Advertisement
Table of Contents
