Siemens NAN 67 Series Manual de Serviço descarregar pdf (Página 245)

20-11

Ladder Logic (LAD) for S7-300 and S7-400

C79000-G7076-C504-02

The instruction ––(MCRA) activates the function MCR up to the next MCRD. The instructions

between ––(MCR<) and ––(MCR>) are processed dependent on the MA bit (here I 0.0):

S If the signal state of input I 0.0 = 1, the following conditions can exist:

– Output Q 4.0 is set to 1 if the signal state of input I 0.3 is 1.

– Output Q 4.0 remains unchanged if the signal state of input I 0.3 is 0.

– The signal state of input I 0.4 is assigned to output Q 4.1.

S If the signal state of input I 0.0 = 0, the following conditions exist:

– Output Q 4.0 remains unchanged regardless of the signal state of input I 0.3.

– Output Q 4.1 is 0 regardless of the signal state of input I 0.4.

I 0.3

Q 4.0

I 0.4

Q 4.1

MCRA

MCR<

I 0.0

MCR>

MCRD

Status Word Bits

BR CC 1 CC 0 OV OS OR STA RLO FC

Write – – – – – – – – –

Figure 20-6 Master Control Relay (Activate and Deactivate)

You must program the dependency of the functions (FCs) and function blocks

(FBs) in the blocks by yourself. If this function or function block is called

from an MCRA/MCRD sequence, not all instructions within this sequence

are automatically dependent on the MCR bit. To achieve this, use the

instruction MCRA of the block called.

Warning

Risk of personal injury and danger to equipment:

Never use the instruction MCR as an EMERGENCY OFF or safety device

for personnel.

MCR is not a substitute for a hardwired master control relay.

Program Control Instructions

1 2 ... 240 241 242 243 244 245 246 247 248 249 250 ... 317 318

Sem comentários

Siemens NAN 67 Series Manual de Serviço Página 245