Banner EZ-SCREEN­ Safety Light Curtain Systems - Manual (Page 62)

60
P/N 133487
Banner Engineering Corp. • Minneapolis, U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
Overview
60
Banner Engineering Corp. • Minneapolis, U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
EZ-SCREEN
Instruction Manual
Cascadeable EZ-SCREEN
Figure 7-6. Calculating response times for a three-light screen cascade – both Individual and Overall methods
Machine
Control
Machine
Control
Machine
Control
Emitters Receivers Emitters Receivers Emitters Receivers
When contacts (e.g., an E-stop button) are connected to a
cascaded receiver (per Section 7.8), CSSI response time is
40 ms plus the 2 ms adder similar to the defined area Tr.
Tr
(CSSI)
= 40 ms + [(N-1) x 2 ms]
Cascade Configuration vs. Response Time
When light screens of different lengths or different resolutions
(and therefore different response times) are used in one circuit,
their positions in the cascade may become a consideration.
For example, consider the light screen circuits depicted in Figure
7-6. Each example contains three safety light screens, one 1200
mm (with a response time of 40 ms), and two 300 mm light
screens (15 ms response each). Depending on their placement
in the cascade, the individual response time for the same three
light screens can vary from 40 to 44 ms.
EZ-SCREEN
Position #3
40 + 2 + 2 = 44
Individual Response
Time: 44 ms
Emitters Receivers
EZ-SCREEN
Position #3
15 + 2 + 2 = 19
Individual Response
Time: 19 ms
Emitters Receivers
EZ-SCREEN
Position #3
15 + 2 + 2 = 19
Individual Response
Time: 19 ms
Emitters Receivers
EZ-SCREEN
Position #2
15 + 2 = 17
Individual Response
Time: 17 ms
EZ-SCREEN
Position #2
40 + 2 = 42
Individual Response
Time: 42 ms
EZ-SCREEN
Position #2
15 + 2 = 17
Individual Response
Time: 17 ms
EZ-SCREEN
Position #1
Individual Response
Time: 15 ms
EZ-SCREEN
Position #1
Individual Response
Time: 15 ms
EZ-SCREEN
Position #1
Individual Response
Time: 40 ms
Machine
Control
Machine
Control
Machine
Control
System Overall Response Time for all systems shown here is 40 + [(3 – 1) × 2 ms] = 44 ms