DETAILED OPERATION - Section 4
4-4
MTS-3000 OPERATION AND REFERENCE MANUAL
######################################################
0$17$
#
7(67
#
6<67(06
###########################################
CU M004 01A
From POSTFAULT state, only a reset action will restore the MTS-3000 to the PREFAULT state. The reset
action can be initiated by pressing the RESET button.
4.4
TRIGGER/TIMER OPERATION
Transitions between the three fault states is initiated from either the front panel push-button or from external
signals connected to the MTS-3010 Digital I/O module. The three possible trigger actions are START, STOP
and RESET. The basic MTS-3010 Digital I/O module provides two sets of external signal input terminals,
either of which can be configured in one of up to eight modes. The default settings configure INPUT 1 to
operate in the TRIP (i.e. Stop) mode, and INPUT 2 as FLT (i.e. Start) mode. See section 5.7 for further
details on the advanced configurations available.The voltage/current output in the prefault and postfault
states may be set on/off by toggling the [PREFAULT] and [POSTFAULT] respectively.
4.4.1
External Trigger Inputs
The three-terminal inputs of the DIGITAL I/O module allow either external contacts or voltage signals to
trigger fault state transitions. The right and centre terminals detect voltage change-of-state. The left and
centre terminals detect contact impedance change-of-state, such as contact closure. In either case, the
changing of a signal causes a trigger. This could be the disappearance of a signal, thus enabling trigger
action from contact opening/voltage disappearance, as well as the more conventional contact closure/
voltage appearance.
The recommended mode is to use voltage sensing whenever possible, since the voltage sensing terminals
don’t inject a voltage of their own into the circuit under test. Voltage output from the impedance terminals,
although of a very high source impedance (50k ohms), may be sufficient to affect operation time of some
sensitive electronic relays.
Up to 300VDC may be applied to any one of the three terminals without damage. AC voltage should be
avoided due to the inherent poor timing accuracy caused by its continuous level variation. Input impedance
of either pair is greater than 50k ohms. Each input channel has 300VDC galvanic isolation with respect to
system ground and all other inputs and outputs.
4.4.2
Trigger Threshold Levels
The threshold voltage level on the trigger inputs is 10V. This low setting was chosen to accommodate
newer solid state relays with low voltage logic level outputs. However, this low threshold level may cause
false triggering when working in very noisy environments. Threshold levels may be raised, if required.
Please contact Manta Test Systems for details.
4.4.3
Start Trigger (FLT)
A “start” trigger will initiate a transition from PREFAULT state to FAULT state. Pressing the FAULT button
is the most common way to initiate a start trigger. The timer will start synchronously with the transition from
PREFAULT to FAULT state. In some cases, it may be desirable to use a external signal to initiate this
transition instead of the FAULT button. To do so, connect the external start trigger signal to INPUT 2 of the
Digital I/O module.