本設(shè)備擬用于2級(jí)污染工業(yè)環(huán)境中的過(guò)電壓II類應(yīng)用
（如IEC 60664-1中所定義），海拔高達(dá)2000米（6562英尺），無(wú)需降額。
本設(shè)備不適用于居住環(huán)境，可能無(wú)法為無(wú)線電提供足夠的保護(hù)
此類環(huán)境中的通信服務(wù)。
該設(shè)備作為開(kāi)放式設(shè)備提供。它必須安裝在適當(dāng)設(shè)計(jì)的外殼內(nèi)
將存在的特定環(huán)境條件，并適當(dāng)設(shè)計(jì)，以防止
帶電部件的可訪問(wèn)性。外殼必須具有適當(dāng)?shù)淖枞夹阅?，以防止或盡量減少火焰蔓延，
符合5VA的火焰蔓延額定值，如果是非金屬材料，則應(yīng)獲得批準(zhǔn)。外殼內(nèi)部必須
只能使用工具訪問(wèn)。本出版物的后續(xù)章節(jié)可能包含有關(guān)特定
符合某些產(chǎn)品安全認(rèn)證要求的外殼類型額定值。
除本出版物外，請(qǐng)參見(jiàn)以下內(nèi)容：
•工業(yè)自動(dòng)化布線和接地指南，羅克韋爾自動(dòng)化出版物1770-4.1，用于附加安裝
要求
•NEMA標(biāo)準(zhǔn)250和IEC 60529（如適用），用于解釋外殼提供的防護(hù)等級(jí)The card provides 8-bit access to objects in the short address space and 8- and 16-bit access to objects in the standard address space. The VME master selects whether a particular bus cycle accesses short, standard, extended, or long (extended and long are not used on the card) address spaces, and the type of access, through the use of the address modifier codes. The card decodes these address modifier codes and determines the object to be accessed. In addition to selecting one of four spaces available on the VMEbus, address modifier codes also select: • Whether the master is making a supervisory or non-privileged access • Whether the access is to program or data space (for all but short address space accesses) • Whether it is to be a single-object or block access The card can respond to address modifier codes 0x03D, 0x039, 0x02D, and 0x029. Supervisory or non-privileged data accesses may be made to standard address space (0x03D and 0x039 respectively). Supervisory or non-privileged accesses may be made to short address space (0x02D and 0x029 respectively). An access to the card with an address modifier code that is not supported causes a VMEbus error. Position 7 of the card's DIP switch selects whether only supervisory accesses or both supervisory and non-privileged accesses are permitted. The following table shows the switch positions.