Vibro-Meter ABE045 - 6U 19-inch rack

ABE045 - 6U 19-inch rack

In practice, it can take up to 350ms (“confirmation time” + “response time”) after an input

signal goes outside the configured OK levels before it is confirmed and acted upon in a

VM600 system as an OK System failure.

When there is an OK System failure on an AMC8 card:

• For the channel in question, the corresponding status indicator (LED) on the panel of the

card blinks green and an OK level alarm (corresponding to the individual

GlobalChannelOK bit) is signalled.

For example, this can be used to switch a relay on the IOC4T or RLC16 card.

NOTE: Any alarms (A+, D+ and so on) associated with the corresponding monitoring

channel are not inhibited, but remain active.

For an AMC8/IOC8T card pair, the monitoring performed by the OK system depends on the

type of sensor input, as follows:

• Thermocouple (TC) devices:

No line-fault detection (open-circuit or short-circuit conditions).

• Resistance temperature detector (RTD) devices:

Line-fault detection of open-circuit and short-circuit conditions.

• DC signals (current or voltage):

Line-fault detection of open-circuit and short-circuit conditions.

NOTE: When a measurement channel of an AMC8/IOC8T card pair is configured for

operation with thermocouple (TC) devices, the sensor input does not support

line-fault detection of conditions such as an open-circuit.

When a thermocouple (TC) device is connected to a measurement channel of an

AMC8/IOC8T card pair and one of the connections becomes open-circuit (that is, the

thermocouple is effectively disconnected), a temperature measurement deviation will occur

until either the minimum or maximum measurable temperature is reached and any configured

alarms (alert and/or danger levels) are activated.

In practice, such a temperature measurement deviation occurs quite slowly with reported

temperature measurements of the order of approximately 10°C (18°F) per second.

5.9.2Built-in self test (BIST)

The AMC8 and IOC8T feature built-in self test (BIST) circuitry which provides information

about the operational state of the system. There are basically three types:

1-Global Board BIST

This tests the IOC as a whole and includes a logic watchdog.

2-Channel BIST

This checks each channel to establish whether:

• The shield (S) terminal is incorrectly connected to the sensor (S) terminal

• The linear regulator voltage is correct

• The DC-DC output voltage is correct

Sensor-Specific BIST

Depending on whether a thermocouple, RTD device, voltage-based sensor or

current-based sensor is connected, performs various tests such as:

• Current source checks

• Line checks (to monitor for broken lines)

• Line resistance mismatch (for 3-wire RTD measurements)

• Correct setting of jumper J805.

Errors detected by the BIST are used to set flags that can then be used by the VM600 MPSx

software to switch relays and so on.

5.10AMC8 power-up sequence

The AMC8 card's power-up sequence is initiated by either of the following events:

• The AMC8 being inserted into the ABE04x rack when the latter is powered up (that is,

the "live insertion" situation).

• Power being re-established after a power-down or a power failure.

5.10.1Power-up after live insertion

A +5VDC pre-charge supply is used to enable live insertion of AMC8 cards. This voltage is

supplied to the AMC8 from the system backplane. It is passed to the AMC8 module via three

pins on connector P1 (see Figure3-3). These pins are slightly longer than the other VME bus

connector pins.

When a module is inserted into a MPS rack that is powered up, these longer pins make

contact first (typically 200ms before the other pins). During this time, the +5VDC pre-charge

supply is used to power up all the +5VDC parts on the module. This ensures that when the

bus driver makes contact with the running VME bus, the circuitry is already at approximately

the correct voltage. In this way no glitches are produced on the VME bus power, address or

data pins.

Once the rest of the pins (including the standard +5VDC supply) make contact, no further

power is drawn from the +5VDC pre-charge supply