CHAPTER 4
(cont.)
TELEVAC
Analog Output Wiring
Provisions are made to connect the instrument to a chart recorder or programmable logic
controller. Two different format signals are provided and are described in Section 5
Analog Outputs. In all cases follow the external device manufacturer’s instructions for
wiring and using these signals. Linear (
LIN
) output is computer generated so that the
voltage signal is plotted as a straight line as a function of pressure.
Traditional (
TRDL
) signal is one that represents the non-linear signal that is
representative of the actual raw sensor data. The 4A Convection version has
Linear/Decade
and
Linear
outputs. By means of a factory settable internal jumper a full
range Traditional signal is available in lieu of the
Linear/Decade
recorder output. Please
refer to Section 5
Analog Output (4A) for a summary of the signals available
Relay Contact Wiring (Set point Relays)
There are four set point relays available for use to control ON/OFF or Open/close (binary
state) devices. The relays are assignable to any one of the vacuum signal input channels
through front panel software control.
There are three connections for each relay. They are NORMALLY CLOSED (NC),
COMMON (C) and NORMALLY OPEN (O). The operation mode of each is described
as follows.
NORMALLY CLOSED:
In this state there is an electrical continuity path between terminals
C
and
NC
. This
continuity path is broken when the software set point values dictates an ON state for the
specific measurement channel. Continuity is returned when the OFF state is dictated by
software control. In the power off mode of the MC300 (due to failure of the main power
source or turning off the instrument), the relay will revert to this state.
NORMALLY OPEN:
In this state there is no electrical continuity path between terminals
C
and
NO
. This Path
is established ONLY when the Instrument control software satisfies conditions for the
ON state. It will break continuity under the instrument control parameters for the OFF
condition or the power off mode of the MC300 (due to failure of the main power source
or turning off the instrument).
Phone:(215) 947-2500 fax:(215) 947-7464 e-mail: sales@televac.com web site:www.televac.com
6-8000-002 REV A
12
