Wika T53 Uživatelský manuál stáhnout pdf (Strana 5)

1.0 The Resource Block, Fieldbus Foundation

1.1 Introduction

The resource block is used to define a hardware specific characteristics of the function block

applications. It provides WIKA manufacturer’s name, device name, DD and block status and

hardware details. It also indicates how much resource (memory and CPU) is available and

controls the overall device.

1.2 Description

This block contains data that is specific to the hardware that is associated with the resource.

All data is modelled within a controlled space, so there are no outside inputs into this block

required.

This parameter “set” is intended to be the minimum required for the Function Block Applica

tion associated with the resource in which it resides. Some parameters that could be in the

set, like calibration data and ambient temperature, are more part of their respective trans

ducer blocks. The “mode” is used to control major states of the resource. O/S mode stops

all function block execution. The actual mode of the function blocks will be changed to O/S

(out of service), but the target mode will not be changed. Auto mode allows normal operation

of the resource. IMan shows that the resource is initializing or receiving a software down

load. Parameters MANUFAC_ID, DEV_TYPE, DEV_REV, DD_REV, and DD_RESOURCE are

required to identify and locate the DD so that Device Description Hosting Services can se

lect the correct DD for use with the resource. The parameter HARD_TYPES is a read only bit

string that indicates the types of hardware that are available to this resource. If an I/O block

is configured that requires a type of hardware that is not available, the result will be a block

alarm for a configuration error. The RS_STATE parameter contains the operational state of

the Function Block Application for the resource containing this resource block.

1.3 RESTART parameter

The RESTART parameter allows degrees of initialization of the resource. They are:

1 - Run: it is the passive state of the parameter

2 - Restart resource: it is intended to clear up problems for example the memory manage

ment resource.

3 - Restart with defaults: it is intended to wipe configuration memory, it works like a factory

initialization.

4 - Restart processor: it provides a way to hit the reset button on the processor associated

with the resource This parameter does not appear in a view because it returns to 1 shortly

after being written.

1.4 Non-volatile parameters

All non-volatile parameters are saved in EEPROM and therefore used if the device is restart

ed.

1.5 Timeout for remote cascade modes

SHED_RCAS and SHED_ROUT set the time limit for loss of communication from a remote

device. These constants are used by all function blocks that support a remote cascade

mode. The effect of a timeout is described in Mode Calculation. Shedding from RCAS/ROUT

shall not happen when SHED_RCAS or SHED_ROUT is set to zero.

1.6 Alert Notification

The MAX_NOTIFY parameter value is the maximum number of alert reports that this resource

can have sent without getting a confirmation, corresponding to the amount of buffer space

available for alert messages. A user can set the number lower than that, to control alert

flooding, by adjusting the LIM_NOTIFY parameter value. If LIM_NOTIFY is set to zero, then

no alerts are reported. The CONFIRM_TIME parameter is the time for the resource to wait for

confirmation of receipt of a report before trying again. If the CONFIRM_TIME = 0 the device

shall not retry.

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