Watlow MLS - Manual (Page 25)

Introduction
MLS User’s Guide 13
The RTB is a screw terminal interface for control wiring which allows
you to easily connect external "real world" wiring to the MLS. The RTB
connects a 50-pin flat ribbon cable to a screw terminal block which
accepts #18 or #20 AWG wires. The ribbon cable receptacle has a
locking latch which keeps the cable in place.
The RTB's 34 digital outputs are sink outputs referenced to the +5 Vdc
power supply of the MLS Controller. They are Low when the output is
On. The firmware allows you to globally change the alarm and control
outputs' default state (no alarms) from On to Off for System Safe output.
The outputs are rated at a continuous 10 mAdc if all outputs are On at
the same time. Initial power up current should not exceed 20 mAdc.
MLS-AIM and AIM-TB Technical Description
The MLS Analog Input Module (MLS-AIM), containing the AIM-TB
(AIM Terminal Board) and AIM’s plug-in cards, receive input signals
from sensors and pass them to the MLS-PM.
The MLS-AIM-TB contains the power supply terminals, input signal
wiring screw terminals, input signal conditioning circuits, and terminal
connections for the AIM's plug-in cards. It also contains a cold junction
temperature sensor and room for the input scaling resistors, if required.
(RTDs, inputs greater than 60 mVdc, and mAdc current inputs require
input scaling resistors.) The AIM-TB has three slots for the plug-in
AIM cards.
There are two versions of the MLS-AIM: the AIM-16 and AIM-32. The
AIM-16 has one multiplexer (MUX) card, and the AIM-32 has two
MUX cards. These cards multiplex the 16 inputs each card receives.
Each -10 to 60 mVdc input is converted to a voltage that is transmitted
to the Voltage/Frequency (V/F) card. (The MUX cards also
automatically calibrate the zero and span of the analog amplifier and
measure the cold junction compensation temperature for thermocouple
(T/C) inputs.) Both the AIM-16 and AIM-32 have a V/F card, which
converts the input signal they receive from a voltage to a frequency. The
converted signal is then transmitted via the AIM COMM cable to the
MLS-PM for processing.